humulene and Schizophrenia

Schizophrenia (SCZ) is a multifactorial neurodevelopmental disorder caused by genetic and environmental alterations, especially during prenatal stages. On the other hand, cannabis consumption in adolescence has been also linked to an increased risk of developing SCZ. The combination of both hits has been proposed as the dual hit hypothesis of SCZ. We systematically reviewed prenatal environmental alterations and cannabis consumption during adolescence that are associated with an increased risk of SCZ, following the PRISMA model. The analysis focused on dual animal models where the first hit is prenatal environmental exposure and the second hit consists of postnatal cannabis exposure. The articles were evaluated by three independent reviewers based on inclusion criteria. We extracted the first author´s name, year, model species, sex and analysis. The articles reported on dual murine models and their effects on weight, behavior, genetics, electrophysiology and brain structure and function. We conclude that the defects caused by the dual hits depend on the sex of the model, as well as type of hits.

Topics: Animals; Brain; Cannabis; Female; Humans; Mice; Pregnancy; Prenatal Exposure Delayed Effects; Risk Factors; Rodentia; Schizophrenia

The study aimed to review recent literature not included in previous reviews and ascertain the correlation between early marijuana use among adolescents, between 12 and 18 years of age, and the development of schizophrenia in early adulthood. A further aim was to determine if the frequency of use of marijuana demonstrated any significant effect on the risk of developing schizophrenia in early adulthood.. Five hundred and ninety-one studies were examined; six longitudinal cohort studies were analyzed using a series of nonparametric tests and meta-analysis.. Nonparametric tests, Friedman tests, and Wilcoxon signed tests showed a highly statistically significant difference in odds ratios for schizophrenia between both high- and low-cannabis users and no-cannabis users.. Both high- and low-frequency marijuana usage were associated with a significantly increased risk of schizophrenia. The frequency of use among high- and low-frequency users is similar in both, demonstrating statistically significant increased risk in developing schizophrenia.

Topics: Adolescent; Adult; Cannabis; Humans; Longitudinal Studies; Schizophrenia

Despite decades of research, the precise etiology of schizophrenia is not fully understood. Ample evidence indicates that the disorder derives from a complex interplay of genetic and environmental factors during vulnerable stages of brain maturation. Among the plethora of risk factors investigated, stress, pre- and perinatal insults, and cannabis use have been repeatedly highlighted as crucial environmental risk factors for schizophrenia. Compelling findings from population-based longitudinal studies suggest low income as an additional risk factor for future schizophrenia diagnosis, but underlying mechanisms remain unclear. In this narrative review, we (1) summarize the literature in support of a relationship between low (parental) income and schizophrenia risk, and (2) explore the mediating role of chronic stress, pre- and perinatal factors, and cannabis use as established risk factors for schizophrenia. Our review describes how low income facilitates the occurrence and severity of these established risk factors and thus contributes to schizophrenia liability. The broadest influence of low income was identified for stress, as low income was found to be associated with exposure to a multitude of severe psychological and physiological stressors. This narrative review adds to the growing literature reporting a close relationship between income and mental health.

Topics: Cannabis; Female; Humans; Poverty; Pregnancy; Risk Factors; Schizophrenia

Topics: Cannabis; Humans; Marijuana Abuse; Mental Health; Schizophrenia; Schizophrenic Psychology; Systemic Inflammatory Response Syndrome

Compared with the general population, there are more cannabis users among patients suffering from schizophrenia and this consumption seems to impact the course and the treatment of their pathology. The aim of this meta-analysis and systematic review was to assess the impact of cannabis use on the efficacy of treatments, more particularly regarding the antipsychotic dosage, symptoms evolution, therapeutic resistance and the risk of relapse in patients with schizophrenia taking medication. We performed a systematic search of keywords on multiple databases up to August 2020 to identify all studies meeting the following criteria: comparison between cannabis smokers and non-cannabis users in patients with schizophrenia, assessment of antipsychotics doses, information about their efficacy or resistance to treatment and control of the compliance. Standardized mean differences were calculated for antipsychotic dosage and symptoms evolution at discharge, and a systematic review was performed for other outcomes. Twelve studies were included. Cannabis use did not seem to be associated with higher doses of antipsychotics at seven days and at the end of the studies, nor with poorer symptoms evolution, and nor with higher rate of antipsychotic resistance. However, cannabis use seems to be associated with a higher risk of relapse. This meta-analysis provides evidence that previous cannabis use, or occasional use, in patients with schizophrenia taking medication does not impact antipsychotic efficacy as described by antipsychotic dosage or PANSS score.

Topics: Antipsychotic Agents; Cannabis; Humans; Schizophrenia

Cannabis is among the most widely consumed psychoactive substances worldwide. Individual differences in cannabis use phenotypes can partly be explained by genetic differences. Technical and methodological advances have increased our understanding of the genetic aetiology of cannabis use. This narrative review discusses the genetic literature on cannabis use, covering twin, linkage, and candidate-gene studies, and the more recent genome-wide association studies (GWASs), as well as the interplay between genetic and environmental factors. Not only do we focus on the insights that these methods have provided on the genetic aetiology of cannabis use, but also on how they have helped to clarify the relationship between cannabis use and co-occurring traits, such as the use of other substances and mental health disorders. Twin studies have shown that cannabis use is moderately heritable, with higher heritability estimates for more severe phases of use. Linkage and candidate-gene studies have been largely unsuccessful, while GWASs so far only explain a small portion of the heritability. Dozens of genetic variants predictive of cannabis use have been identified, located in genes such as CADM2, FOXP2, and CHRNA2. Studies that applied multivariate methods (twin models, genetic correlation analysis, polygenic score analysis, genomic structural equation modelling, Mendelian randomisation) indicate that there is considerable genetic overlap between cannabis use and other traits (especially other substances and externalising disorders) and some evidence for causal relationships (most convincingly for schizophrenia). We end our review by discussing implications of these findings and suggestions for future work.

Topics: Cannabis; Genome-Wide Association Study; Multifactorial Inheritance; Phenotype; Schizophrenia

Cannabis (

Topics: Alzheimer Disease; Analgesics; Cannabinoid Receptor Agonists; Cannabinoids; Cannabis; Glaucoma; Humans; Multiple Sclerosis; Parkinson Disease; Proteome; Proteomics; Schizophrenia

Western democracies continue to 'legalize recreational cannabis use' after its 'medicinal approval', while India continues to debate whether to 'decriminalize' cannabis or not. One of the strongest arguments against cannabis decriminalization is cannabis dependence and the risk of psychosis, at-least in the vulnerable groups. Endocannabinoids are involved in neuronal proliferation and differentiation during 'patterning of the central nervous system'. Aberrant neurostimulation caused by repeated heavy exo-cannabinoid exposure may increase the probability of pro-psychotic experiences. Various animal and human studies have demonstrated increased but abnormal activation of cortical and subcortical areas due to chronic cannabis use. Some of these areas are involved in the pathogenesis of psychosis or schizophrenia. A review of the literature was done to hypothesize the possible role of cannabis to cause (or precipitate) psychosis through repeated "aberrant neurostimulation". The 'aberrant neurostimulation model of cannabis psychosis' may explain pathogenesis, individual vulnerabilities and developing therapeutic strategies for this debated entity. In future, well designed placebo-controlled studies may find the answer with more confidence.

Topics: Animals; Cannabinoids; Cannabis; Humans; Marijuana Abuse; Psychotic Disorders; Schizophrenia

Topics: Animals; Cannabinoids; Cannabis; COVID-19 Drug Treatment; Drug Discovery; Drug Synergism; Endocannabinoids; Epilepsy; Humans; Inflammatory Bowel Diseases; Parkinson Disease; Phytochemicals; Receptors, Cannabinoid; Schizophrenia; Terpenes; Tourette Syndrome

Cannabis use is considered an important risk factor for the development of psychotic illness and is associated with worse outcomes of the disorder. This study aimed to determine through a meta-analytic approach whether patients at the onset of schizophrenia with comorbid cannabis use (SCH CU+) show a different pattern of brain abnormalities as compared to patients with no comorbid cannabis use (SCH CU-). Ten Magnetic Resonance Imaging (MRI) studies were identified as suitable for analysis leading to the inclusion of n= 465 patients with schizophrenia (n= 227 SCH CU+ and n= 238 SCH CU-) and n= 366 healthy controls. Compared to healthy controls, both SCH CU+ and SCH CU- patients showed reduction of whole brain, total grey matter and hippocampal volumes. The direct comparison of SCH CU+ and SCH CU- patients, including up to 5 independent studies, did not demonstrate significant differences of brain volumes between the two groups even though total and regional grey matter volume deficits were more prominent in SCH CU+ patients. The available literature data indicate that, essentially, there is an overlap of brain abnormalities in SCH CU+ and SCH CU- patients at the onset of schizophrenia. The common vs specific trajectories of brain pathomorphology in SCH CU+ and SCH CU- patients are discussed.

Topics: Brain; Cannabis; Gray Matter; Humans; Magnetic Resonance Imaging; Schizophrenia

Medicinal use of

Topics: Alzheimer Disease; Anxiety; Bicyclic Monoterpenes; Cannabidiol; Cannabinoid Receptor Agonists; Cannabis; Cognitive Dysfunction; Dronabinol; Humans; Inflammatory Bowel Diseases; Neuralgia; Neuroprotective Agents; Nootropic Agents; Schizophrenia; Sesquiterpenes; Terpenes

Many factors and their interaction are linked to the aetiology of schizophrenia, leading to the development of animal models of multiple risk factors and adverse exposures. Differentiating between separate and combined effects for each factor could better elucidate schizophrenia pathology, and drive development of preventative strategies for high-load risk factors. An epidemiologically valid risk factor commonly associated with schizophrenia is adolescent cannabis use. The aim of this review is to evaluate how early-life adversity from various origins, in combination with adolescent cannabinoid exposure interact, and whether these interactions confer main, synergistic or protective effects in animal models of schizophrenia-like behavioural, cognitive and morphological alterations. Patterns emerge regarding which models show consistent synergistic or protective effects, particularly those models incorporating early-life exposure to maternal deprivation and maternal immune activation, and sex-specific effects are observed. It is evident that more research needs to be conducted to better understand the risks and alterations of interacting factors, with particular interest in sex differences, to better understand the translatability of these preclinical models to humans.

Topics: Adolescent; Animals; Cannabinoids; Cannabis; Disease Models, Animal; Female; Humans; Male; Maternal Deprivation; Risk Factors; Schizophrenia

Despite the high prevalence in patients with schizophrenia, the association of cannabis and nicotine use with negative symptoms remains unclear. We performed a meta-analysis of observational studies addressing the association of cannabis and nicotine use with negative symptoms. Twenty cannabis studies (n = 2611) and 45 nicotine studies (n = 8942) were analyzed. There was no significant effect for current cannabis use alone or in combination with other substances. However, recently abstinent users of cannabis showed less severe negative symptoms than nonusers. Nicotine users were not different from nonusers with respect to negative symptoms. With respect to positive symptoms, very small increases were found for cannabis users and patients using nicotine along with other drugs. In conclusion, while patients with schizophrenia who use cannabis did not differ from nonusers, recently abstinent patients showed less severe negative symptoms than nonusers. This finding suggests that cannabis-using patients might be less susceptible to the development of negative symptoms. The amotivational effects of cannabis may obscure these differences in current users.

Topics: Cannabis; Hallucinogens; Humans; Marijuana Abuse; Nicotine; Observational Studies as Topic; Schizophrenia

Evidence for an association between cannabis and psychosis has been documented in literature in many forms including experimental studies, epidemiological data, and case series. The association has implications for psychotic outcomes ranging from mild to severe and occurring over minutes to years. Due to the huge variety of exposures and outcome measures reported, creating a coherent account of all the available information is difficult. A useful way to conceptualize these wide-ranging results is to consider the association between cannabis and psychosis as it occurs within the context of widely used DSM-5 diagnoses. In the present review we examine cannabis/psychosis associations as they pertain to Cannabis Intoxication, Cannabis-Induced Psychotic Disorder, and Schizophrenia. This allows for an understanding of the cannabis and psychosis association along something approaching a continuum. Cannabis intoxication becomes Cannabis-Induced Psychotic Disorder once certain severity and duration criteria are met and Cannabis-Induced Psychotic Disorder is heavily associated with future schizophrenia diagnoses.

Topics: Age Factors; Cannabis; Catechol O-Methyltransferase; Diagnostic and Statistical Manual of Mental Disorders; Genetic Predisposition to Disease; Humans; Male; Marijuana Abuse; Psychoses, Substance-Induced; Schizophrenia; Time Factors

This paper provides an update from the literature on understanding of the relationship between cannabis and schizophrenia. In particular, the paper focuses on the latest findings and remaining areas that require investigation.. Three hypotheses have emerged as potential explanations for the association between cannabis and schizophrenia, namely cannabis can trigger schizophrenia, cannabis is used to mitigate symptoms of schizophrenia, and there are common factors which might account for the association. Biological and genetic factors dominate this field of research; this has been at the expense of exploring social and cultural contributory factors which influence cannabis and schizophrenia. The evidence for cannabis acting as a causal factor for schizophrenia has so far not been established. Research needs to extend beyond males drawn from western countries if we are to advance knowledge and understanding of the link between cannabis use and schizophrenia.

Topics: Cannabis; Humans; Male; Marijuana Abuse; Psychotic Disorders; Risk Factors; Schizophrenia

Cannabis consumption produces psychopathology, in some cases psychotic episodes, which are of our interest in this work. However, the relationship between cannabis use and psychosis has not been fully elucidated. The objectives of this work are to (1) review the current state of knowledge on the association of cannabis use with the risk of the development of psychosis or psychotic symptoms in people without schizophrenia and (2) assess the consistency of the hypothesis that cannabis use is associated with increased risk of psychosis in people without schizophrenia.. This work included research done in humans until May 2018 with the keywords 'cannabis' and 'psychosis', published in English and Spanish, in the PubMed database.. In all, 66 papers were analyzed, of which 23 were cohort trials and 43 were reviews.. Cannabis use doubles the risk of developing psychosis in vulnerable people. There even exists a relationship regarding the dose used and the age of first use. Gene-environment interactions that modulate the association between cannabis use and the presence of psychosis have also been described.

Topics: Cannabis; Gene-Environment Interaction; Humans; Marijuana Abuse; Psychotic Disorders; Risk Factors; Schizophrenia

Cannabis is a widely used illicit drug and its use is often associated with co-occurring psychiatric disorders. This systematic review was aimed to provide information on the published Indian studies on co-occurring cannabis use disorders and psychiatric disorders.. An electronic search of available Indian literature using relevant search terms was carried out in May 2015 and 52 articles in English language published from India were included in the current review.. Studies on cannabis and associated psychotic disorders (n=16) chiefly described acute episodes with predominant positive symptoms, following cannabis use. Some studies (n=6) observed an overall increased prevalence of all psychiatric disorders and symptoms owing to cannabis use, while others (n=14) elaborated on high rates of substance use in those with psychiatric disorders. The effect of cannabis use on cognitive function was the focus of some of the Indian studies (n=7). All these studies barring one had all male subjects, and a single study described the service delivery model for those with dual diagnosis disorders in India. Most of the research used cross-sectional observational design and focussed on treatment-seeking population.. A review of Indian literature on cannabis use and its association with psychiatric disorders indicates a high co-prevalence of psychotic disorders, especially in vulnerable individuals as well as high rates of co-occurrence of other psychiatric comorbidities. However, there is limited focus on exploring the aetiological association between cannabis use and psychiatric disorders; understanding the neurobiology of this association and management-related issues.

Topics: Cannabis; Comorbidity; Humans; India; Psychotic Disorders; Research; Schizophrenia; Substance-Related Disorders

Heavy cannabis use has been frequently associated with increased rates of mental illness and cognitive impairment, particularly amongst adolescent users. However, the neurobiological processes that underlie these associations are still not well understood. In this review, we discuss the findings of studies examining the acute and chronic effects of cannabis use on the brain, with a particular focus on the impact of commencing use during adolescence. Accumulating evidence from both animal and human studies suggests that regular heavy use during this period is associated with more severe and persistent negative outcomes than use during adulthood, suggesting that the adolescent brain may be particularly vulnerable to the effects of cannabis exposure. As the endocannabinoid system plays an important role in brain development, it is plausible that prolonged use during adolescence results in a disruption in the normative neuromaturational processes that occur during this period. We identify synaptic pruning and white matter development as two processes that may be adversely impacted by cannabis exposure during adolescence. Potentially, alterations in these processes may underlie the cognitive and emotional deficits that have been associated with regular use commencing during adolescence.

Topics: Adolescent; Animals; Brain; Cannabinoids; Cannabis; Depression; Endocannabinoids; Female; Humans; Learning Disabilities; Memory Disorders; Pregnancy; Prenatal Exposure Delayed Effects; Schizophrenia

The impact of cannabis use on the brain tissue is still unclear, both in the healthy developing brain and in people with schizophrenia. The focus of this review is on white matter, the primary connective infrastructure of the brain.. We systematically reviewed diffusion tensor imaging (DTI) studies of early phase schizophrenia (illness effect), of cannabis use in otherwise healthy brains (drug effect), and of early phase schizophrenia with cannabis use (combined effects). Studies had to include a healthy, non-cannabis using, control group as well as report on fractional anisotropy as it is the most commonly used DTI index. We excluded cohorts with heavy alcohol or illicit drug use and studies with a sample size of less than 20 in the clinical group.. We retained 17 studies of early phase schizophrenia, which together indicate deficits in white matter integrity observed in all fiber tract families, but most frequently in association, callosal and projection fibers. In otherwise healthy cannabis users (2 studies), deficits in white matter tracts were reported mainly in callosal fibers, but also in projection and limbic fibers. In cannabis users with early phase schizophrenia (1 study), deficits in white matter integrity were also observed in all fiber tract families, except for limbic fibers.. The current literature points to several families of white matter tracts being differentially affected in early phase schizophrenia. Further work is required to reveal the impact of cannabis use in otherwise healthy people as well as those with schizophrenia.. Paucity of available studies as well as restricting analysis to FA values represent the main limitations of this review.

Topics: Brain; Cannabis; Diffusion Tensor Imaging; Humans; Marijuana Smoking; Nerve Fibers, Myelinated; Schizophrenia; White Matter

The role of cannabis in the etiology of schizophrenia has been documented as possibly the strongest environmental risk factor. However, the pathomechanism whereby cannabis use increases this risk has not yet been identified. We argue that this pathomechanism may involve direct effects of exogenous cannabinoids on T-type calcium channels in the thalamus. These channels are crucial for amplification of corticothalamic inputs, as well as for the ability of the thalamus to generate neuronal burst firing. Cortically induced thalamic burst firing has been found to be important in trans-thalamic cortico-cortical interactions. Therefore, any potential interference with the burst firing mode in the thalamus could lead to an impairment in these interactions, which in turn causes a relative disconnection between cortical areas. This in turn could result in reduced ability to recognize re-afferent sensory inputs and psychosis. We also argue that the effects of Δ(9)THC are more detrimental compared with the effects of cannabidiol, as the former may increase the excitability of thalamic neurons by its direct effect on T-type calcium channels.

Topics: Animals; Calcium Channels, T-Type; Cannabinoids; Cannabis; Cerebral Cortex; Dronabinol; Electroencephalography; Hallucinogens; Humans; Neural Pathways; Psychoses, Substance-Induced; Psychotic Disorders; Schizophrenia; Schizophrenic Psychology; Thalamus

Cannabis is widely used in adolescence; however, the effects of cannabis on the developing brain remain unclear. Cannabis might be expected to have increased effects upon brain development and cognition during adolescence. There is extensive re-organisation of grey (GM) and white matter (WM) at this time, while the endocannabinoid (eCB) system, which is involved in the normal physiological regulation of neural transmission, is still developing. In healthy adolescent cannabis users there is a suggestion of greater memory loss and hippocampal volume changes. Functional studies point to recruitment of greater brain areas under cognitive load. Structural and DTI studies are few, and limited by comorbid drug and alcohol use. The studies of cannabis use in adolescent-onset schizophrenia (AOS) differ, with one study pointing to extensive GM and WM changes. There is an intriguing suggestion that the left parietal lobe may be more vulnerable to the effects of cannabis in AOS. As in adult schizophrenia cognition does not appear to be adversely affected in AOS following cannabis use. Given the limited number of studies it is not possible to draw firm conclusions. There is a need for adequately powered, longitudinal studies.

Topics: Adolescent; Brain; Cannabis; Cognition; Dronabinol; Health; Humans; Marijuana Abuse; Nerve Fibers, Myelinated; Nerve Fibers, Unmyelinated; Neuropsychological Tests; Parietal Lobe; Psychometrics; Schizophrenia; Sex Characteristics

Estimate the prevalence of cannabis dependence and its contribution to the global burden of disease.. Systematic reviews of epidemiological data on cannabis dependence (1990-2008) were conducted in line with PRISMA and meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines. Culling and data extraction followed protocols, with cross-checking and consistency checks. DisMod-MR, the latest version of generic disease modelling system, redesigned as a Bayesian meta-regression tool, imputed prevalence by age, year and sex for 187 countries and 21 regions. The disability weight associated with cannabis dependence was estimated through population surveys and multiplied by prevalence data to calculate the years of life lived with disability (YLDs) and disability-adjusted life years (DALYs). YLDs and DALYs attributed to regular cannabis use as a risk factor for schizophrenia were also estimated.. There were an estimated 13.1 million cannabis dependent people globally in 2010 (point prevalence0.19% (95% uncertainty: 0.17-0.21%)). Prevalence peaked between 20-24 yrs, was higher in males (0.23% (0.2-0.27%)) than females (0.14% (0.12-0.16%)) and in high income regions. Cannabis dependence accounted for 2 million DALYs globally (0.08%; 0.05-0.12%) in 2010; a 22% increase in crude DALYs since 1990 largely due to population growth. Countries with statistically higher age-standardised DALY rates included the United States, Canada, Australia, New Zealand and Western European countries such as the United Kingdom; those with lower DALY rates were from Sub-Saharan Africa-West and Latin America. Regular cannabis use as a risk factor for schizophrenia accounted for an estimated 7,000 DALYs globally.. Cannabis dependence is a disorder primarily experienced by young adults, especially in higher income countries. It has not been shown to increase mortality as opioid and other forms of illicit drug dependence do. Our estimates suggest that cannabis use as a risk factor for schizophrenia is not a major contributor to population-level disease burden.

Topics: Age Factors; Cannabis; Comorbidity; Disabled Persons; Female; Geography, Medical; Global Health; Humans; Male; Marijuana Abuse; Prevalence; Risk Factors; Schizophrenia; Sex Factors

There is convincing evidence that schizophrenia is characterised by progressive brain volume changes during the course of the illness. In a large longitudinal study it was shown that different age-related trajectories of brain tissue loss are present in patients compared to healthy subjects, suggesting that brain maturation that occurs in the third and fourth decade of life is abnormal in schizophrenia. However, studies show that medication intake and cannabis use are important confounding factors when interpreting brain volume (change) abnormalities. Indeed, continues use of cannabis, but not cigarette smoking, is associated to a more pronounced loss of grey matter in the anterior cingulated and the prefrontal cortex. Atypical antipsychotics have been found to be related to smaller decreases in tissue loss. Moreover, independent of antipsychotic medication intake, the brain volume abnormalities appear associated to the outcome of the illness.

Topics: Antipsychotic Agents; Atrophy; Brain; Cannabis; Disease Progression; Gyrus Cinguli; Humans; Nerve Fibers, Unmyelinated; Prefrontal Cortex; Prognosis; Schizophrenia; Smoking

Although cannabis use disorder is strongly related to schizophrenia and treatment of patients with double diagnosis provides serious problem, specific pharmacological, molecular and therapeutical data on this subgroup are poorly available. In this paper we present a critical review on psychopharmacological boundaries of schizophrenia with concurrent cannabis use. The relevant data available in the literature suggest that a weaker compliance, poorer therapy response and higher sensitivity for extrapyramidal side effects are key features of schizophrenia and comorbid cannabis use disorder and represent a clinical challenge. Because of paucity of available research in the field there is not enough evidence to clearly depict the exact psychopharmacological profile of cannabis related schizophrenia. Further investigations are needed to assess phenotypic characteristics of this entity and to tailor effective treatment options accordingly.

Topics: Antipsychotic Agents; Cannabis; Humans; Marijuana Abuse; Psychopharmacology; Schizophrenia

Cannabis is the most prevalent illicit substance used among schizophrenia patients. The effects of cannabis are mediated through the endocannabinoid system, which is a major regulator of neurotransmission and may be disturbed in schizophrenia. Though cognitive impairment in schizophrenia is well established, the effects of cannabis on cognition in schizophrenia patients are still unclear. This paper reviews 19 studies that examine the cognitive effects of cannabis on schizophrenia by comparing cognitive functioning of cannabis-using and non-using schizophrenia patients across a vast range of domains (memory, attention and processing speed, executive functions, visuospatial, psychomotor and language). Of the studies included in the review, 11 reported better cognitive functions among cannabis-using schizophrenia patients compared to non-users, 5 found minimal or no difference between the groups and 3 found poorer cognitive functions among cannabis-using schizophrenia patients compared to non-users. The inconsistencies in the studies reviewed may stem from significant methodological variance between the studies regarding patient selection, adequate controls, cognitive measures used, measures of cannabis use, additional drugs used, and clinical aspects of schizophrenia. These methodological issues are discussed, as well as possible explanations for the results presented and suggestions for future research in this field.

Topics: Cannabis; Humans; Marijuana Abuse; Schizophrenia; Schizophrenic Psychology

There is considerable evidence to suggest that the abuse of illicit drugs, particularly cannabis and methamphetamine, has aetiological roles in the pathogenesis of psychosis and schizophrenia. Factors that may increase susceptibility to the propsychotic effects of these drugs include the age at which the abuse starts as well as family history of genetic polymorphisms relevant to the pathophysiology of this disorder. However, the neurobiological mechanisms involved in drug abuse-associated psychosis remain largely unclear.. This paper presents an overview of the available evidence, including clinical, animal model, and molecular studies, with a focus on brain regions and neurotransmitters systems, such as dopamine and glutamate, previously implicated in psychosis.. It is clear that further studies are urgently needed to provide a greater insight into the mechanisms that mediate the long-term and neurodevelopmental effects of cannabis and methamphetamine. A dialogue between basic science and clinical research may help to identify at-risk individuals and novel pathways for treatment and prevention.

Topics: Age of Onset; Animals; Behavioral Symptoms; Brain; Cannabis; Dopamine; Dopamine Uptake Inhibitors; Functional Neuroimaging; Genetic Predisposition to Disease; Glutamic Acid; Humans; Illicit Drugs; Methamphetamine; Models, Animal; Psychoses, Substance-Induced; Risk Factors; Schizophrenia; Substance-Related Disorders

Numerous studies have shown that patients with psychosis are more likely to use illicit drugs than the general population, with cannabis being the most popular. There exists overwhelming evidence that cannabis use can contribute to the onset of schizophrenia and poor outcome in patients with established psychosis. Therefore, understanding why patients use cannabis and whether they are motivated to change their habits is important. The evidence is that patients with psychosis use cannabis for the same reasons the general population does, to 'get high', relax and have fun. There is little support for the 'self-medication' hypothesis, while the literature points more towards an 'alleviation of dysphoria' model. There is a lack of research reporting on whether psychotic patients are ready to change their use of cannabis, which has obvious implications for identifying which treatment strategies are likely to be effective.

Topics: Cannabis; Comorbidity; Humans; Marijuana Abuse; Models, Theoretical; Psychoses, Substance-Induced; Psychotic Disorders; Risk Factors; Schizophrenia; Self Medication; Self Report

Cannabis use during adolescence increases the risk of developing psychotic disorders later in life. However, the neurobiological processes underlying this relationship are unknown. This review reports the results of a literature search comprising various neurobiological disciplines, ultimately converging into a model that might explain the neurobiology of cannabis-induced schizophrenia. The article briefly reviews current insights into brain development during adolescence. In particular, the role of the excitatory neurotransmitter glutamate in experience-dependent maturation of specific cortical circuitries is examined. The review also covers recent hypotheses regarding disturbances in strengthening and pruning of synaptic connections in the prefrontal cortex, and the link with latent psychotic disorders. In the present model, cannabis-induced schizophrenia is considered to be a distortion of normal late postnatal brain maturation. Distortion of glutamatergic transmission during critical periods may disturb prefrontal neurocircuitry in specific brain areas. Our model postulates that adolescent exposure to Δ9-tetrahydrocannabinol (THC), the primary psychoactive substance in cannabis, transiently disturbs physiological control of the endogenous cannabinoid system over glutamate and GABA release. As a result, THC may adversely affect adolescent experience-dependent maturation of neural circuitries within prefrontal cortical areas. Depending on dose, exact time window and duration of exposure, this may ultimately lead to the development of psychosis or schizophrenia. The proposed model provides testable hypotheses which can be addressed in future studies, including animal experiments, reanalysis of existing epidemiological data, and prospective epidemiological studies in which the role of the dose-time-effect relationship should be central.

Topics: Adolescent; Brain; Cannabinoid Receptor Modulators; Cannabis; Dronabinol; Humans; Marijuana Abuse; Models, Neurological; Nerve Net; Neurobiology; Neurotransmitter Agents; Receptors, AMPA; Receptors, N-Methyl-D-Aspartate; Risk Factors; Schizophrenia; Synapses

Impaired cognitive functioning, including deficits in working memory, is considered to be a core and disabling feature of schizophrenia that is difficult to treat. Deficits in working memory in schizophrenia are attributable, at least in part, to specific pathological alterations in the neuronal circuitry of the dorsolateral prefrontal cortex that involve, but are not restricted to, disturbances in glutamate, GABA, and dopamine neurotransmission. Cannabis use provides an example of an environmental exposure that may have a deleterious impact on these neurotransmitter systems and thereby contribute to worsening of cognitive functioning in schizophrenia. Increasing knowledge of the nature of the molecular alterations in these cortical circuits may lead to the development of new pathophysiologically informed treatment options for cognitive deficits in schizophrenia.

Topics: Animals; Cannabis; Cognition Disorders; Humans; Marijuana Abuse; Models, Neurological; Nerve Net; Neurons; Prefrontal Cortex; Schizophrenia

Recent advances in knowledge about cannabinoid receptor function have renewed interest in the association between cannabis and psychosis. Case series, autobiographical accounts, and surveys of cannabis users in the general population suggest an association between cannabis and psychosis. Cross-sectional studies document an association between cannabis use and psychotic symptoms, and longitudinal studies suggest that early exposure to cannabis confers a close to two-fold increase in the risk of developing schizophrenia. Pharmacological studies show that cannabinoids can induce a full range of transient positive, negative, and cognitive symptoms in healthy individuals that are similar to those seen in schizophrenia. There is considerable evidence that in individuals with an established psychotic disorder such as schizophrenia, exposure to cannabis can exacerbate symptoms, trigger relapse, and worsen the course of the illness. Only a very small proportion of the general population exposed to cannabis develop a psychotic illness. It is likely that cannabis exposure is a 'component cause' that interacts with other factors to 'cause' schizophrenia or other psychotic disorder, but is neither necessary nor sufficient to do so alone. Further work is necessary to identify the factors that underlie individual vulnerability to cannabinoid-related psychosis and to elucidate the biological mechanisms underlying this risk.

Topics: Animals; Cannabinoids; Cannabis; Humans; Marijuana Abuse; Marijuana Smoking; Psychotic Disorders; Receptors, Cannabinoid; Risk Factors; Schizophrenia

The association between cannabis use and psychosis has long been recognized. Recent advances in knowledge about cannabinoid receptor function have renewed interest in this association. Converging lines of evidence suggest that cannabinoids can produce a full range of transient schizophrenia-like positive, negative, and cognitive symptoms in some healthy individuals. Also clear is that in individuals with an established psychotic disorder, cannabinoids can exacerbate symptoms, trigger relapse, and have negative consequences on the course of the illness. The mechanisms by which cannabinoids produce transient psychotic symptoms, while unclear may involve dopamine, GABA, and glutamate neurotransmission. However, only a very small proportion of the general population exposed to cannabinoids develop a psychotic illness. It is likely that cannabis exposure is a "component cause" that interacts with other factors to "cause" schizophrenia or a psychotic disorder, but is neither necessary nor sufficient to do so alone. Nevertheless, in the absence of known causes of schizophrenia, the role of component causes remains important and warrants further study. Dose, duration of exposure, and the age of first exposure to cannabinoids may be important factors, and genetic factors that interact with cannabinoid exposure to moderate or amplify the risk of a psychotic disorder are beginning to be elucidated. The mechanisms by which exposure to cannabinoids increase the risk for developing a psychotic disorder are unknown. However, novel hypotheses including the role of cannabinoids on neurodevelopmental processes relevant to psychotic disorders are being studied.

Topics: Association; Cannabis; Cognition Disorders; Humans; Marijuana Abuse; Neurotransmitter Agents; Psychotic Disorders; Schizophrenia

Cannabis abuse and endocannabinoids are associated to schizophrenia.. It is important to discern the association between schizophrenia and exogenous Cannabis sativa, on one hand, and the endogenous cannabinoid system, on the other hand.. On one hand, there is substantial evidence that cannabis abuse is a risk factor for psychosis in genetically predisposed people, may lead to a worse outcome of the disease, or it can affect normal brain development during adolescence, increasing the risk for schizophrenia in adulthood. Regarding genetic predisposition, alterations affecting the cannabinoid CNR1 gene could be related to schizophrenia. On the other hand, the endogenous cannabinoid system is altered in schizophrenia (i.e., increased density of cannabinoid CB1 receptor binding in corticolimbic regions, enhanced cerebrospinal fluid anandamide levels), and dysregulation of this system can interact with neurotransmitter systems in such a way that a "cannabinoid hypothesis" can be integrated in the neurobiological hypotheses of schizophrenia. Finally, there is also evidence that some genetic alterations of the CNR1 gene can act as a protectant factor against schizophrenia or can induce a better pharmacological response to atypical antipsychotics.. Cannabis abuse is a risk factor for psychosis in predisposed people, it can affect neurodevelopment during adolescence leading to schizophrenia, and a dysregulation of the endocannabinoid system can participate in schizophrenia. It is also worth noting that some specific cannabinoid alterations can act as neuroprotectant for schizophrenia or can be a psychopharmacogenetic rather than a vulnerability factor.

Topics: Adolescent; Animals; Cannabinoid Receptor Modulators; Cannabis; Endocannabinoids; Genetic Predisposition to Disease; Humans; Marijuana Abuse; Receptor, Cannabinoid, CB1; Risk Factors; Schizophrenia

Many people with schizophrenia use cannabis and its effects on the illness are unclear.. To evaluate the effects of cannabis use on people with schizophrenia and schizophrenia-like illnesses.. We searched the Cochrane Schizophrenia Group Trials Register (April 2007) which is based on regular searches of BIOSIS, CENTRAL, CINAHL, EMBASE, MEDLINE and PsycINFO.. We included all randomised trials involving cannabinoids and people with schizophrenia or schizophrenia-like illnesses.. We extracted data independently. For dichotomous data we calculated relative risks (RR) and their 95% confidence intervals (CI) on an intention-to-treat basis, based on a fixed effects model. We calculated the numbers needed to treat/harm (NNT/NNH). For continuous data, we calculated weighted mean differences (WMD) again based on a fixed effects model.. We identified one randomised trial. No significant differences were found between the Cannabis and Psychosis Therapy (CAP) intervention group and the Psychoeducaton (PE) intervention for use of cannabis at three months assessment (n=47, RR 1.04 CI 0.6 to 1.7). BPRS-extended scale scores at three months assessment (n=47, WMD -3.60 CI -12.8 to 5.6) and nine months assessment (n=47, WMD 0.80 CI -7.5 to 9.1) were non-significant between CAP and PE. We found no significant improvement in social functioning in the CAP group compared with PE (at 3 months, n=47, WMD -0.80 CI -10 to 8.4) and (at 9 months, n=47, WMD -4.70 CI -14.5 to 5.1).. At present, there is insufficient evidence to support or refute the use of cannabis/cannabinoid compounds for people suffering with schizophrenia. This review highlights the need for well designed, conducted and reported clinical trials to address the potential effects of cannabis based compounds for people with schizophrenia.

Topics: Cannabinoids; Cannabis; Humans; Schizophrenia

The aim of this review is to describe the historical development of research on cannabidiol.. This review was carried out on reports drawn from Medline, Web of Science and SciELO.. After the elucidation of the chemical structure of cannabidiol in 1963, the initial studies showed that cannabidiol was unable to mimic the effects of Cannabis. In the 1970's the number of publications on cannabidiol reached a first peak, having the research focused mainly on the interaction with delta9-THC and its antiepileptic and sedative effects. The following two decades showed lower degree of interest, and the potential therapeutic properties of cannabidiol investigated were mainly the anxiolytic, antipsychotic and on motor diseases effects. The last five years have shown a remarkable increase in publications on cannabidiol mainly stimulated by the discovery of its anti-inflammatory, anti-oxidative and neuroprotective effects. These studies have suggested a wide range of possible therapeutic effects of cannabidiol on several conditions, including Parkinson's disease, Alzheimer's disease, cerebral ischemia, diabetes, rheumatoid arthritis, other inflammatory diseases, nausea and cancer.. In the last 45 years it has been possible to demonstrate that CBD has a wide range of pharmacological effects, many of which being of great therapeutic interest, but still waiting to be confirmed by clinical trials.

Topics: Anti-Anxiety Agents; Anti-Inflammatory Agents; Antiemetics; Antineoplastic Agents; Antioxidants; Antipsychotic Agents; Biomedical Research; Cannabidiol; Cannabis; Diabetes Mellitus; Humans; Mental Disorders; Neuroprotective Agents; Parkinson Disease; Schizophrenia

Cannabis is the most consumed illicit drug. For a number of years it was thought to be not very toxic, although this idea has no scientific backup. The object of much controversy, it is a public health problem for the most vulnerable populations, adolescents, subjects with evolutive psychopathologies and certain highly cognitive situations: driving a car, the professional environment and students. Cannabis breeds, in international classifications of mental disorders, intoxication charts, abuse and dependence, although this last could have been challenged. The complications are basically anxious and psychotic. It is the object of a number of debates associated with schizophrenic disorders, where it seems to be a risk factor where there is a large consumption before the age of fourteen. Like all psychoactive substances, it is an aggravating factor in all evolutive psychopathologies.

Topics: Adolescent; Adult; Anxiety; Cannabis; Humans; Marijuana Abuse; Mental Disorders; Psychoses, Substance-Induced; Schizophrenia; Young Adult

This review explores what is known about the association of cannabis with schizophrenia, its effects on the brain, and whether the brain changes known to be present in schizophrenia could be caused by cannabis and thus lead to a psychosis.. The heavy use of cannabis is known to be associated with some adverse consequences, such as the occurrence of acute psychotic episodes and the development of chronic schizophrenia in some people even after its use has terminated. Recent studies have produced controversy about whether cannabis in heavy use can cause irreversible brain damage, particularly to adolescents, and thus whether a chronic psychosis could be a result of brain changes caused by cannabis.. From the evidence that exists, it appears that the above view is unlikely and that cannabis may even have benign effects on brain structure, not producing deleterious damage. Its neurochemical interactions with the dopaminergic pathway, however, may, particularly in genetically vulnerable individuals, have adverse consequences.

Topics: Brain; Cannabis; Humans; Magnetic Resonance Imaging; Marijuana Abuse; Prevalence; Psychoses, Substance-Induced; Risk Factors; Schizophrenia

Understanding of the neurophysiological basis of cognitive, behavioural and perceptual disturbances associated with long-term cannabis use has grown dramatically. Exogenous cannabinoids alter the normative functioning of the endogenous cannabinoid system. This system is an important regulator of neurotransmission. Recent research has demonstrated abnormalities of the cannabinoid system in schizophrenia. The purpose of the present paper was to selectively review the links between cannabis use and psychosis, drawing upon recent epidemiological, clinical, cognitive, brain imaging and neurobiological research. The aim is to assist clinicians to probe more deeply into the newly unfolding world of cannabinoid physiology and to critically evaluate the potential role of cannabis in the onset and persistence of cognitive impairments and psychosis in otherwise healthy users and in schizophrenia.

Topics: Animals; Brain; Cannabinoid Receptor Modulators; Cannabinoids; Cannabis; Cognition Disorders; Humans; Psychoses, Substance-Induced; Schizophrenia; Schizophrenic Psychology

The link between cannabis use and psychosis has been studied intensively and debated hotly for decades. The authors review the research that has been done on the topic, including the studies which produced evidence of a relationship between the two phenomena, and give a detailed analysis of the hypotheses about the nature of the link (the direction of causality). According to the reviewed literature an increased prevalence of cannabis use can be found in the schizophrenic population. The use of the drug is associated with a worse prognosis and an earlier onset of schizophrenia. However, findings about the possible effect of cannabis use on the specific symptoms of schizophrenia have been contradictory. An association has also been observed between cannabis use and schizotypal personality traits, but evidence for a specific, cannabis induced functional psychosis is still lacking. Based on the data of longitudinal studies, cannabis use should be recognized as a risk factor for later psychosis. The abuse of the drug increases the likelihood of later psychotic symptoms especially among individuals with vulnerability or when the use starts in early adolescence. At the same time, the role of self-medication or a common genetic background cannot be excluded either, and a circular causality is very possible.

Topics: Age of Onset; Cannabis; Disease Susceptibility; Humans; Marijuana Abuse; Prognosis; Psychoses, Substance-Induced; Risk Factors; Schizophrenia; Self Medication

Drug models of mental illness are considered useful if they provoke its characteristic symptoms. In this respect, ketamine and tetrahydrocannabinol (cannabis) are coming under increasing scrutiny as models for schizophrenia. However, although both undoubtedly produce psychotic symptoms characteristic of the disorder, we argue here that, because schizophrenia is also accompanied by cognitive deficits, a full understanding of the impact of these drugs on cognition will be crucial in taking these models further. Memory deficits are pronounced in schizophrenia and we focus upon patterns of working and episodic memory impairment produced by ketamine and cannabis, identifying overlaps between drug and illness. We suggest that close attention to these deficits can offer insights into core pathophysiology of schizophrenia.

Topics: Age Factors; Animals; Attention; Cannabis; Evoked Potentials; Humans; Ketamine; Memory Disorders; Memory, Short-Term; Schizophrenia

A high dose of delta9-tetrahydrocannabinol, the main Cannabis sativa (cannabis) component, induces anxiety and psychotic-like symptoms in healthy volunteers. These effects of delta9-tetrahydrocannabinol are significantly reduced by cannabidiol (CBD), a cannabis constituent which is devoid of the typical effects of the plant. This observation led us to suspect that CBD could have anxiolytic and/or antipsychotic actions. Studies in animal models and in healthy volunteers clearly suggest an anxiolytic-like effect of CBD. The antipsychotic-like properties of CBD have been investigated in animal models using behavioral and neurochemical techniques which suggested that CBD has a pharmacological profile similar to that of atypical antipsychotic drugs. The results of two studies on healthy volunteers using perception of binocular depth inversion and ketamine-induced psychotic symptoms supported the proposal of the antipsychotic-like properties of CBD. In addition, open case reports of schizophrenic patients treated with CBD and a preliminary report of a controlled clinical trial comparing CBD with an atypical antipsychotic drug have confirmed that this cannabinoid can be a safe and well-tolerated alternative treatment for schizophrenia. Future studies of CBD in other psychotic conditions such as bipolar disorder and comparative studies of its antipsychotic effects with those produced by clozapine in schizophrenic patients are clearly indicated.

Topics: Animals; Anti-Anxiety Agents; Antipsychotic Agents; Cannabidiol; Cannabis; Clinical Trials as Topic; Disease Models, Animal; Humans; Mental Disorders; Mice; Rats; Schizophrenia

The comorbidity of schizophrenia and substance abuse has attracted increasing attention in the past years, with multiple potential links, including genetic vulnerability, neurobiological aspects, side effects of medications, and psychosocial factors being under discussion. The link between the use of substances and the development of psychoses is demonstrated by the high prevalence of substance abuse in schizophrenia. Apart from alcohol misuse, substances commonly abused in this patient group include nicotine, cocaine, and cannabis. In particular, heavy cannabis abuse has been reported to be a stressor eliciting relapse in schizophrenic patients. In general, substance use in psychosis is associated with poorer outcomes, including increased psychotic symptoms and poorer treatment compliance. Since both disorders have been observed to be closely interdependent, a particular treatment for schizophrenic patients with comorbidity of substance abuse is needed in order to provide more effective care. In this article, we discuss various potential modes of interaction and interdependence, and the possibility of embarking on new therapeutic paths for treating this particular population.

Topics: Cannabis; Cocaine; Humans; Nicotine; Schizophrenia; Substance-Related Disorders

Controversy remains as to whether cannabis acts as a causal risk factor for schizophrenia or other functional psychotic illnesses.. To examine critically the evidence that cannabis causes psychosis using established criteria of causality.. We identified five studies that included a well-defined sample drawn from population-based registers or cohorts and used prospective measures of cannabis use and adult psychosis.. On an individual level, cannabis use confers an overall twofold increase in the relative risk for later schizophrenia. At the population level, elimination of cannabis use would reduce the incidence of schizophrenia by approximately 8%, assuming a causal relationship. Cannabis use appears to be neither a sufficient nor a necessary cause for psychosis. It is a component cause, part of a complex constellation of factors leading to psychosis.. Cases of psychotic disorder could be prevented by discouraging cannabis use among vulnerable youths. Research is needed to understand the mechanisms by which cannabis causes psychosis.

Topics: Adolescent; Adult; Cannabis; Humans; Prognosis; Psychotic Disorders; Research Design; Risk Factors; Schizophrenia; Time Factors

To study the role of cannabis use in the onset of symptoms and disorders in the schizophrenia spectrum.. Review of five population-based, longitudinal studies on the relationship between cannabis use and problems ranging from the experience of psychotic symptoms to hospitalization with a confirmed diagnosis of schizophrenia. Several hypotheses are examined that may explain this relationship: (1) self-medication; (2) effects of other drugs; (3) confounding; (4) stronger effect in predisposed people, and (5) etiological hypothesis.. Hypotheses 1 and 2 can be dismissed; hypothesis 3 is still open to debate, and converging evidence is found for hypotheses 4 and 5-antecedent cannabis use appears to act as a risk factor in the onset of schizophrenia, especially in vulnerable people, but also in people without prior history.. There is an intrinsic message here for public health, but how that message is to be translated into action is not immediately clear.

Topics: Age of Onset; Cannabis; Female; Follow-Up Studies; Humans; Male; Marijuana Smoking; Psychoses, Substance-Induced; Risk Factors; Schizophrenia

Recent research has clarified a number of important questions concerning adverse effects of cannabis on health. A causal role of acute cannabis intoxication in motor vehicle and other accidents has now been shown by the presence of measurable levels of Delta(9)-tetrahydrocannabinol (THC) in the blood of injured drivers in the absence of alcohol or other drugs, by surveys of driving under the influence of cannabis, and by significantly higher accident culpability risk of drivers using cannabis. Chronic inflammatory and precancerous changes in the airways have been demonstrated in cannabis smokers, and the most recent case-control study shows an increased risk of airways cancer that is proportional to the amount of cannabis use. Several different studies indicate that the epidemiological link between cannabis use and schizophrenia probably represents a causal role of cannabis in precipitating the onset or relapse of schizophrenia. A weaker but significant link between cannabis and depression has been found in various cohort studies, but the nature of the link is not yet clear. A large body of evidence now demonstrates that cannabis dependence, both behavioral and physical, does occur in about 7-10% of regular users, and that early onset of use, and especially of weekly or daily use, is a strong predictor of future dependence. Cognitive impairments of various types are readily demonstrable during acute cannabis intoxication, but there is no suitable evidence yet available to permit a decision as to whether long-lasting or permanent functional losses can result from chronic heavy use in adults. However, a small but growing body of evidence indicates subtle but apparently permanent effects on memory, information processing, and executive functions, in the offspring of women who used cannabis during pregnancy. In total, the evidence indicates that regular heavy use of cannabis carries significant risks for the individual user and for the health care system.

Topics: Accidents, Traffic; Automobile Driving; Cannabis; Cardiovascular Diseases; Cognition Disorders; Cohort Studies; Dronabinol; Humans; Longitudinal Studies; Marijuana Abuse; Marijuana Smoking; Neurotoxicity Syndromes; Psychomotor Performance; Public Health; Respiratory Tract Diseases; Risk; Schizophrenia

The prevalence of substance abuse is elevated among schizophrenic patients. When free of illicit substances and sober, substance-abusing schizophrenic patients may have a better prognosis than other frequently hospitalized schizophrenic patients. However, the cost of substance abuse is great in terms of rehospitalization, homelessness, risk of other medical illness, disruption of social and vocational function, exacerbation of symptoms, suicide, and increased health care expenses. Important recent developments in medications for reducing substance abuse in nonschizophrenic populations make it timely to consider factors that might contribute to substance abuse among schizophrenic patients. This review will focus on substances most frequently abused by schizophrenic patients: nicotine, alcohol, cannabis, and psychostimulants. It concentrates on two conceptual foci: "self-medication hypotheses" and "comorbid addiction vulnerability hypotheses". The relationship between these hypotheses and possible pharmacotherapeutic approaches for substance-abusing schizophrenic patients will be considered.

Topics: Antipsychotic Agents; Basal Ganglia Diseases; Cannabis; Central Nervous System Stimulants; Cocaine; Cognition Disorders; Dopamine; Health Care Costs; Humans; Nicotine; Schizophrenia; Schizophrenic Psychology; Substance-Related Disorders

The usual phenomena of cannabis intoxication include experiences which in a non-intoxicated state would be considered as psychiatric symptoms. These can be distinguished from adverse reactions to cannabis, the commonest of which is an acute anxiety state. Acute psychotic episodes can also follow ingestion of the drug but are infrequent. These can be classified as acute confusional states and episodes occurring in clear consciousness. Neither presentation consistently shows enough specific features to warrant the diagnosis of 'cannabis psychosis' as a distinct clinical entity. The evidence that cannabis has a causative role in chronic psychotic or affective disorders is not convincing, although the drug may modify the course of an already established illness. Further controlled studies would be required to clarify the aetiological significance of the drug in these conditions.

Topics: Anxiety; Cannabis; Humans; Marijuana Abuse; Marijuana Smoking; Mood Disorders; Motivation; Psychotic Disorders; Schizophrenia

Violence is a symptom of an underlying mental state such as a psychosis, a characterological problem, or brain dysfunction. Thus drugs used to treat aggression in man exert effects by their specific pharmacological actions (e.g., antipsychotic, anticonvulsant). Most literature to date has dealt with animals and human models of aggression and lacks conceptual clarity. Aggression differs from depression, a coherent clinical entity, in its etiological diversity and its paroxysmal or impulsive basis, and this may account for the relationship seen in literature linking violence to epilepsy; yet literature on anticonvulsants is equivocal with regard to beneficial effects on aggression. Lithium has been shown to have positive effects, although its mode of action is unclear. A variety of antipsychotic agents and minor tranquilizers have been mentioned. Central nervous system stimulants have been found useful to treat hyperkinetic syndromes in both children and adults where aggression is a symptom. Hormonal agents are discussed. Drug treatment of aggression should not obscure the need for verbal therapies, and social and environmental factors should always be regarded.

Topics: Adolescent; Adult; Aggression; Alcoholic Intoxication; Animals; Anti-Anxiety Agents; Anticonvulsants; Antipsychotic Agents; Attention Deficit Disorder with Hyperactivity; Butyrophenones; Cannabis; Chlordiazepoxide; Disease Models, Animal; Epilepsy; Gonadal Steroid Hormones; Humans; Hyperkinesis; Impulsive Behavior; Lithium; Male; Methadone; Paranoid Disorders; Phenothiazines; Phenytoin; Psychopharmacology; Psychosurgery; Schizophrenia; Thiothixene; Violence

Topics: Amphetamine; Bipolar Disorder; Cannabis; Diagnosis, Differential; Female; Humans; Lysergic Acid Diethylamide; Male; Psychoses, Substance-Induced; Schizophrenia; Substance-Related Disorders

Topics: Affective Symptoms; Antidepressive Agents; Butyrophenones; Cannabis; Clinical Trials as Topic; Humans; Lithium; Lysergic Acid Diethylamide; Mental Disorders; Methadone; Nicotinic Acids; Pentylenetetrazole; Phenothiazines; Psychopharmacology; Schizophrenia; Substance-Related Disorders; Thiothixene; Trifluoperazine

Topics: Adrenochrome; Cannabis; Hallucinogens; Humans; Lysergic Acid Diethylamide; Mescaline; Metabolism; Psychological Tests; Psychotherapy; Psychotic Disorders; Schizophrenia; Toxicology

Cannabis use is common in first-episode psychosis (FEP) but evidence is mixed about the extent to which cannabis use predicts symptoms and functional outcomes among those who seek treatment. This study sought to characterize cannabis use patterns and examine the relationship with clinical outcomes, including interactions with early intervention services (EIS). Data were drawn from the Recovery After an Initial Schizophrenia Episode-Early Treatment Program (RAISE-ETP) study including FEP individuals receiving treatment at sites randomized to provide either EIS (NAVIGATE) or community care (CC). Cannabis use was assessed monthly and symptom and functioning data were collected at baseline, 6, 12, 18, and 24 months. Among the 404 participants enrolled, 334 were classified into four cannabis use groups (consistent, sporadic, stopped, and never users) based on their use during the first year. Consistent and sporadic cannabis users were younger, whereas those who had stopped using were older. Sporadic users had the highest depression and the lowest functioning at baseline and improved less during treatment in negative emotions and intrapsychic foundations (e.g., motivation and sense of purpose) than non-users. However, sporadic users who received NAVIGATE improved more in overall symptoms and functioning than those who received CC. Consistent users did not tend to differ in their trajectories from non-users. Individuals with FEP who use cannabis sporadically showed less clinical improvement than non-users. However, EIS treatment reduced the negative effects of sporadic cannabis use on clinical outcomes. Those who use cannabis sporadically may have unique needs that require attention in EIS.

Topics: Cannabis; Humans; Psychotic Disorders; Schizophrenia

Marijuana use may increase schizophrenia risk, and this effect may be genetically moderated. We investigated how hypothetical genetic test results indicating the presence or absence of heightened schizophrenia risk in reaction to marijuana use would affect attitudes toward marijuana use. In two experiments, participants were randomized to hypothetical scenarios in which genetic testing showed the presence or absence of a predisposition for marijuana use to increase their schizophrenia risk, or to a control condition with no mention of genetic testing. Experiment 1 used a sample of 801 U.S. young adults recruited via Amazon.com's Mechanical Turk platform. Experiment 2 replicated the same procedures with a nationally representative sample of 800 U.S. adults aged 18-30. In Experiment 1, those in the predisposition condition, compared to the control condition, rated the likelihood and importance of their avoiding marijuana as significantly higher, whereas those in the no-predisposition condition rated both as significantly lower. In experiment 2, these findings were largely replicated for the predisposition condition but not the no-predisposition condition, and prior marijuana use was a significant moderator, with the effects of the predisposition condition confined to participants who reported having used marijuana. If these results are predictive of responses to actual genetic testing, they suggest that genetic test results indicating that marijuana use will increase one's schizophrenia risk may incentivize abstinence, especially for those with prior marijuana use. Future research could further investigate whether genetic test results indicating the absence of such a predisposition might disincentivize abstinence from marijuana use.

Topics: Cannabis; Humans; Marijuana Abuse; Marijuana Smoking; Marijuana Use; Schizophrenia; Substance-Related Disorders; Young Adult

Topics: Affective Symptoms; Antidepressive Agents; Butyrophenones; Cannabis; Clinical Trials as Topic; Humans; Lithium; Lysergic Acid Diethylamide; Mental Disorders; Methadone; Nicotinic Acids; Pentylenetetrazole; Phenothiazines; Psychopharmacology; Schizophrenia; Substance-Related Disorders; Thiothixene; Trifluoperazine

Topics: Adolescent; Adult; Antidepressive Agents; Antiparkinson Agents; Butyrophenones; Cannabis; Chlorprothixene; Clinical Trials as Topic; Drug Therapy; Drug Therapy, Combination; Extrapyramidal Tracts; Heroin Dependence; Humans; Hypnotics and Sedatives; Lysergic Acid Diethylamide; Mental Disorders; Movement Disorders; Niacinamide; Nicotinic Acids; Phenothiazines; Placebos; Schizophrenia; Thiothixene; Tranquilizing Agents

The consequences of cannabis use, especially in the context of schizophrenia, have gained increased importance with the legalization of cannabis in North America and across the globe. Cannabis use has multifaceted impacts on cognition in schizophrenia patients and healthy subjects. Healthy subjects, particularly those who initiated cannabis use at earlier ages and used high-potency cannabis for longer durations, exhibited poorer cognition mainly in working memory and attention. Cannabis use in schizophrenia has been associated with symptom exacerbation, longer and more frequent psychotic episodes, and poorer treatment outcomes. However, cannabis-using patients have better overall cognitive performance compared to patients who were not cannabis users. Interestingly, these effects were only apparent in lifetime cannabis users, but not in current (or within last 6 months) users. Moreover, higher frequency and earlier age of cannabis use initiation (i.e., before 17 years of age) were associated with better cognitive performance, although they had an earlier illness onset. Three possible hypotheses seem to come forward to explain this paradox. First, some components of cannabis may have antipsychotic or cognitive-enhancing properties. Secondly, chronic cannabis use may alter endocannabinoid signaling in the brain which could be a protective factor for developing psychosis or cognitive impairments. A third explanation could be their representation of a phenotypically distinct patient group with more intact cognitive functioning and less neurodevelopmental pathology. Multiple factors need to be considered to understand the complex relationship between cannabis, cognitive function, and schizophrenia. In short, age at initiation, duration and rate of cannabis use, abstinence duration, co-use of substances and alcohol, prescribed medications, relative cannabinoid composition and potency of cannabis, presence of genetic and environmental vulnerability factors are prominent contributors to the variability in outcomes. Animal studies support the disruptive effects of Δ9-tetrahydrocannabinol (THC) administration during adolescence on attention and memory performance. They provide insights about interaction of cannabinoid receptors with other neurotransmitter systems, such as GABA and glutamate, and other regulatory molecules, such as PSD95 and synaptophysin. Cannabidiol (CBD), on the other hand, can improve cognitive deficits seen in neurodevelopmental and chemically-i

Topics: Adolescent; Animals; Cannabinoids; Cannabis; Cognition; Dronabinol; Hallucinogens; Humans; Schizophrenia

Risk for cannabis use and schizophrenia is influenced in part by genetic factors, and there is evidence that genetic risk for schizophrenia is associated with subclinical psychotic-like experiences (PLEs). Few studies to date have examined whether genetic risk for schizophrenia is associated with cannabis-related PLEs.. We tested whether measures of cannabis involvement and polygenic risk scores (PRS) for schizophrenia were associated with self-reported cannabis-related experiences in a sample ascertained for alcohol use disorders (AUDs), the Collaborative Study on the Genetics of Alcoholism (COGA). We analyzed 4832 subjects (3128 of European ancestry and 1704 of African ancestry; 42% female; 74% meeting lifetime criteria for an AUD).. Cannabis use disorder (CUD) was prevalent in this analytic sample (70%), with 40% classified as mild, 25% as moderate, and 35% as severe. Polygenic risk for schizophrenia was positively associated with cannabis-related paranoia, feeling depressed or anhedonia, social withdrawal, and cognitive difficulties, even when controlling for duration of daily cannabis use, CUD, and age at first cannabis use. The schizophrenia PRS was most robustly associated with cannabis-related cognitive difficulties (β = 0.22, SE = 0.04, P = 5.2e-7). In an independent replication sample (N = 1446), associations between the schizophrenia PRS and cannabis-related experiences were in the expected direction and not statistically different in magnitude from those in the COGA sample.. Among individuals who regularly use cannabis, genetic liability for schizophrenia-even in those without clinical features-may increase the likelihood of reporting unusual experiences related to cannabis use.

Topics: Alcoholism; Cannabis; Female; Genetic Predisposition to Disease; Humans; Male; Multifactorial Inheritance; Risk Factors; Schizophrenia

Cannabis use is a common risk factor for psychoses. But although prevalence of consumption as well as potency of cannabis increased, the incidence of schizophrenia remained stable. The discontinuation hypothesis suggests that a potential increase of psychoses incidence may be relativized by more frequent cessation of consumption due to higher rates of adverse psychosis-like intoxication effects (PLE), caused by stronger cannabis. A mixed methods online survey was administered to 441 current and past users to analyze the predictive impact of different acute intoxication effects regarding abstinence motivation/cessation of use. Our hypothesis was that PLE would be experienced as the most aversive intoxication effect and therefore have the highest predictive significance. Possible confounds were included (craving, patterns of consumption and sociodemographics). Further analyzes compared past versus current users regarding the quality of intoxication effects, suggesting that past users retrospectively experienced more unpleasant experiences than current users. Free-text data explored subjective reasons for abstinence. We found that paranoid/dysphoric intoxication effects were most predictive for abstinence motivation. Less predictive were psychosis-like intoxication effects such as hallucinations. Group comparisons revealed significant more unpleasurable and less positive intoxication effects in past users compared with current users. Current users with the intention to stop consumption showed significantly more paranoia/dysphoria intoxication compared to users with no intention to stop use. As a conclusion, different intoxication experiences have different effects on abstinence motivation and substance use behavior. They therefore provide a focus that should be increasingly integrated into treatment concepts.

Topics: Cannabis; Foodborne Diseases; Humans; Motivation; Psychotic Disorders; Retrospective Studies; Schizophrenia

Rates of cannabis use disorder (CUD) are higher in people with schizophrenia than in the general population. Irrespective of psychiatric diagnosis, tobacco co-use is prevalent in those with CUD and leads to poor cannabis cessation outcomes. The cannabis withdrawal syndrome is well-established and increases cannabis relapse risk. We investigated whether cannabis withdrawal severity differed as a function of high versus no/low tobacco dependence and psychiatric diagnosis in individuals with CUD.. Men with CUD (N = 55) were parsed into four groups according to schizophrenia diagnosis and tobacco dependence severity using the Fagerstrom Test for Nicotine Dependence (FTND): men with schizophrenia with high tobacco dependence (SCT+, n = 13; FTND ≥ 5) and no/low tobacco dependence (SCT-, n = 22; FTND ≤ 4), and nonpsychiatric controls with high (CCT+, n = 7; FTND ≥ 5) and no/low (CCT-, n = 13; FTND ≤ 4) tobacco dependence. Participants completed the Marijuana Withdrawal Checklist following 12-h of cannabis abstinence.. There was a significant main effect of tobacco dependence on cannabis withdrawal severity (p < .001). Individuals with high tobacco dependence had significantly greater cannabis withdrawal severity (M = 13.85 [6.8]) compared to individuals with no/low tobacco dependence (M = 6.49, [4.9]). Psychiatric diagnosis and the interaction effects were not significant. Lastly, cannabis withdrawal severity positively correlated with FTND (r = .41, p = .002).. Among individuals with CUD and high tobacco dependence, cannabis withdrawal severity was elevated twofold, irrespective of diagnosis, relative to individuals with CUD and no/low tobacco dependence. Findings from this study emphasize the importance of addressing tobacco co-use when treating CUD.

Topics: Cannabis; Humans; Male; Marijuana Abuse; Schizophrenia; Substance Withdrawal Syndrome; Substance-Related Disorders; Tobacco Use Disorder

This analysis examined the relationship between cannabis use, compliance with antipsychotics and risk for relapse in patients in remission following a first episode of schizophrenia, schizophreniform, or schizoaffective disorder.. Analyses were performed on data from a large European study on first episode of schizophrenia, schizophreniform, or schizoaffective disorder (OPTiMiSE). After 10 weeks of antipsychotic treatment, 282/446 patients (63%) met criteria for symptomatic remission; of whom 134/282 (47.5%) then completed a 1-year follow-up. Cross-lagged models and mediation models investigated the temporal relationships between cannabis use, compliance with antipsychotics, social functioning, and symptomatic worsening/relapse.. Compared to nonusers, cannabis use increased risk for relapse, adjusted hazard ratio (HR) = 3.03 (SE = 0.32), P < .001, even in patients who were compliant with antipsychotic medication, adjusted HR = 2.89, (SE = 0.32), P < .001. Cannabis use preceded symptomatic worsening and was followed by worsening of Positive and Negative Syndrome Scale total score at the 1-year end-point (standardized β = 0.62, SE = 0.19, P = .001) and by worsening of social functioning (coef = -0.66, P ≤ .001).. In patients in remission from their first episode of schizophrenia, schizophreniform, or schizoaffective disorder, cannabis use increases the rate of relapse in both compliant and noncompliant individuals. Importantly, the temporal relationship between cannabis and relapse was that cannabis use preceded later relapse, noncompliance, and decrease in social functioning, and not that patients began to relapse, then used cannabis. Further research with a precision psychiatry approach might identify those patients in particular danger of relapse when using cannabis.

Topics: Antipsychotic Agents; Cannabinoid Receptor Agonists; Cannabis; Hallucinogens; Humans; Psychotic Disorders; Recurrence; Schizophrenia

While evidence strongly supports a causal effect of cannabis on psychosis, it is less clear whether the symptom pattern, clinical course, and outcomes differ in cases of schizophrenia with and without a background of cannabis use.. Analysis of medical records from a longitudinal follow-up of Swedish conscripts with data on cannabis use in adolescence and subsequent incidence of schizophrenia. One hundred sixty patients with schizophrenia were assessed using the OPCRIT protocol. Cases were validated for diagnosis schizophrenia according to OPCRIT.. Patients with a cannabis history (n = 32), compared to those without (n = 128), had an earlier age at onset, a higher number of hospital admissions and a higher total number of hospital days. There was no significant difference in type of onset and clinical symptom profiles between the groups.. Our findings indicate that the disease burden of schizophrenia is greater in individuals who use cannabis during adolescence. Strengthening evidence on causality and teasing out long-term effects of pre-illness cannabis use from continued post-illness has clinical implications for improving schizophrenia outcomes.

Topics: Adolescent; Cannabis; Causality; Humans; Marijuana Abuse; Psychotic Disorders; Schizophrenia

The relationship between psychotic disorders and cannabis use is heavily debated. Shared underlying genetic risk is one potential explanation. We investigated the genetic association between psychotic disorders (schizophrenia and bipolar disorder) and cannabis phenotypes (lifetime cannabis use and cannabis use disorder).. We used genome-wide association summary statistics from individuals with European ancestry from the Psychiatric Genomics Consortium, UK Biobank, and International Cannabis Consortium. We estimated heritability, polygenicity, and discoverability of each phenotype. We performed genome-wide and local genetic correlations. Shared loci were identified and mapped to genes, which were tested for functional enrichment. Shared genetic liabilities to psychotic disorders and cannabis phenotypes were explored using causal analyses and polygenic scores, using the Norwegian Thematically Organized Psychosis cohort.. Psychotic disorders were more heritable than cannabis phenotypes and more polygenic than cannabis use disorder. We observed positive genome-wide genetic correlations between psychotic disorders and cannabis phenotypes (range 0·22-0·35) with a mixture of positive and negative local genetic correlations. Three to 27 shared loci were identified for the psychotic disorder and cannabis phenotype pairs. Enrichment of mapped genes implicated neuronal and olfactory cells as well as drug-gene targets for nicotine, alcohol, and duloxetine. Psychotic disorders showed a causal effect on cannabis phenotypes, and lifetime cannabis use had a causal effect on bipolar disorder. Of 2181 European participants from the Norwegian Thematically Organized Psychosis cohort applied in polygenic risk score analyses, 1060 (48·6%) were females and 1121 (51·4%) were males (mean age 33·1 years [SD 11·8]). 400 participants had bipolar disorder, 697 had schizophrenia, and 1044 were healthy controls. Within this sample, polygenic scores for cannabis phenotypes predicted psychotic disorders independently and improved prediction beyond the polygenic score for the psychotic disorders.. A subgroup of individuals might have a high genetic risk of developing a psychotic disorder and using cannabis. This finding supports public health efforts to reduce cannabis use, particularly in individuals at high risk or patients with psychotic disorders. Identified shared loci and their functional implications could facilitate development of novel treatments.. US National Institutes of Health, the Research Council Norway, the South-East Regional Health Authority, Stiftelsen Kristian Gerhard Jebsen, EEA-RO-NO-2018-0535, European Union's Horizon 2020 Research and Innovation Programme, the Marie Skłodowska-Curie Actions, and University of Oslo Life Science.

Topics: Animals; Bipolar Disorder; Cannabis; Genetic Predisposition to Disease; Genome-Wide Association Study; Marijuana Abuse; Schizophrenia; Substance-Related Disorders

Rates of cannabis use are elevated in early psychosis populations, rendering it difficult to determine if an episode of psychosis is related to cannabis use (e.g., cannabis-induced psychosis), or if substance use is co-occurring with a primary psychotic disorder (e.g., schizophrenia). Clinical presentations of these disorders are often indistinguishable, hindering assessment and treatment. Despite substantial research identifying cognitive deficits, eye movement abnormalities and speech impairment associated with primary psychotic disorders, these neuropsychological features have not been explored as targets for diagnostic differentiation in early psychosis.. Eighteen participants with cannabis-induced psychosis (M. Relative to individuals with primary psychosis, individuals with cannabis-induced psychosis demonstrated significantly better performance on the pro-saccade task, faster RT on pro- and anti-saccade tasks, better premorbid adjustment, and a higher degree of insight into their illness. There were no significant differences between groups on psychiatric symptoms, premorbid intellectual functioning, or problems related to cannabis use.. In early stages of illness, reliance on traditional diagnostic tools or clinical interviews may be insufficient to distinguish between cannabis-induced and primary psychosis. Future research should continue to explore neuropsychological differences between these diagnoses to improve diagnostic accuracy.

Topics: Adult; Cannabis; Humans; Male; Marijuana Abuse; Psychotic Disorders; Schizophrenia; Substance-Related Disorders; Young Adult

It has not yet been determined if the commonly reported cannabis-psychosis association is limited to individuals with pre-existing genetic risk for psychotic disorders.. We examined whether the relationship between polygenic risk score for schizophrenia (PRS-Sz) and psychotic-like experiences (PLEs), as measured by the Community Assessment of Psychic Experiences-42 (CAPE-42) questionnaire, is mediated or moderated by lifetime cannabis use at 16 years of age in 1740 of the individuals of the European IMAGEN cohort. Secondary analysis examined the relationships between lifetime cannabis use, PRS-Sz and the various sub-scales of the CAPE-42. Sensitivity analyses including covariates, including a PRS for cannabis use, were conducted and results were replicated using data from 1223 individuals in the Dutch Utrecht cannabis cohort.. PRS-Sz significantly predicted cannabis use (. These results suggest that cannabis use remains a risk factor for PLEs, over and above genetic vulnerability for schizophrenia. This research does not support the notion that the cannabis-psychosis link is limited to individuals who are genetically predisposed to psychosis and suggests a need for research focusing on cannabis-related processes in psychosis that cannot be explained by genetic vulnerability.

Topics: Adult; Cannabinoid Receptor Agonists; Cannabis; Hallucinogens; Humans; Psychotic Disorders; Schizophrenia; Young Adult

Schizophrenia and comorbid substance use disorders (SUDs) are associated with poor treatment outcomes but differences between the associations of different SUDs with clinical outcomes are poorly characterized. This study examines the associations of comorbid SUDs with clinical outcomes in schizophrenia using a largescale electronic health record (EHR) database.. Real-world data (RWD) analysis using the NeuroBlu database; de-identified EHR data were analysed. Multivariable logistic regression, Poisson and CoxPH models were used to compare the associations of specific comorbid SUDs with outcome variables.. Comorbid SUD was significantly different on all outcome measures compared to no SUD (U = 1.44e. Comorbid SUDs were generally associated with greater CGI-S and poorer clinical outcomes in patients with schizophrenia. Treatment strategies should target not only schizophrenia symptoms but also comorbid SUD to improve management of both conditions.

Topics: Antipsychotic Agents; Cannabis; Cocaine; Cocaine-Related Disorders; Comorbidity; Electronic Health Records; Humans; Schizophrenia; Substance-Related Disorders

The first years following a first-episode psychosis (FEP) are crucial. This retrospective cohort study investigates the evolution of first-episode psychosis (FEP), including substance-induced psychosis (SIP), and explores factors influencing the diagnostic conversion to Schizophrenia or Schizophrenia Spectrum Disorders (SSD). Diagnoses of patients discharged from Basurto University Hospital's inpatient psychiatry unit between January 2002 and December 2016 were reviewed. Sociodemographic, clinical, and substance use data, including cannabinoids, opioids, amphetamines, cocaine, and alcohol, were collected. The analysis utilized descriptive statistics, Kaplan-Meier survival curves, and Cox regression. Among 341 patients, 64.8% were male, with a mean age of 33.8 years. Psychiatric family history was present in 33.4% of cases, and cannabis was the most commonly used substance (78.9%). Of the patients, 52.8% received subsequent diagnoses of Schizophrenia or SSD, with 86.9% of these cases occurring within the first five years. No significant differences were observed between patients diagnosed with SIP and other diagnoses in terms of sociodemographic, clinical characteristics, or progression to Schizophrenia or SSD. However, use of cannabis (compared to use of another substance or polysubstance use) was associated with a higher risk to conversion (HR 1.96; p = 0.001). These findings underscore the importance of addressing substance use and treatment adherence in FEP.

Topics: Adult; Cannabis; Female; Humans; Male; Psychotic Disorders; Retrospective Studies; Schizophrenia; Substance-Related Disorders

Delta-9-tetrahydrocannabinol, a component of marijuana, interacts with cannabinoid receptors in brain involved in memory, cognition, and emotional control. However, marijuana use and schizophrenia development is a complicated and contentious topic. As a result, more investigation is needed to understand this relationship. Through the functional enrichment analysis, we report the delta-9-tetrahydrocannabinol to manipulate the homeostatic biological process and molecular function of different macromolecules. Additionally, using molecular docking and subsequent processing for molecular simulations, we assessed the binding ability of delta-9-tetrahydrocannabinol with the estrogen-related protein, dopamine receptor 5, and hyaluronidase. It was found that delta-9-tetrahydrocannabinol may have an impact on the brain's endocannabinoid system and may trigger the schizophrenia progression in vulnerable people. Delta-9-tetrahydrocannabinol may interfere with the biological function of 18 proteins linked to schizophrenia and disrupt the synaptic transmission (dopamine, glutamine, and gamma-aminobutyric acid). It was discovered that it may affect lipid homeostasis, which is closely related to membrane integrity and synaptic plasticity. The negative control of cellular and metabolic processes, fatty acids binding /activity, and the manipulated endocannabinoid system (targeting cannabinoid receptors) were also concerned with delta-9-tetrahydrocannabinol. Hence, this may alter neurotransmitter signaling involved in memory, cognition, and emotional control, showing its direct impact on brain physiological processes. This may be one of the risk factors for schizophrenia development which is also closely tied to some other variables such as frequency, genetic vulnerability, dosage, and individual susceptibility.

Topics: Cannabis; Dronabinol; Endocannabinoids; Humans; Molecular Docking Simulation; Neurophysiology; Receptors, Cannabinoid; Schizophrenia

Episodes of substance-induced psychosis are associated with increased risk of developing a schizophrenia spectrum disorder. However, there are limited data on the transition risk for substance use without psychosis.. To quantify the risk of transition to schizophrenia spectrum disorder following an incident emergency department (ED) visit for (1) substance-induced psychosis and (2) substance use without psychosis and to explore factors associated with transition.. A population-based retrospective cohort study (January 2008 to March 2022) of all individuals, aged 14 to 65 years, in Ontario, Canada, with no history of a psychotic disorder. Individuals with incident ED visits for substance use with and without psychosis were compared with members of the general population.. Transition to schizophrenia spectrum disorder using a chart-validated algorithm. Associations between ED visits for substance use and subsequent transition were estimated using cause-specific hazard models.. The study included 9 844 497 individuals, aged 14 to 65 years (mean [SD] age, 40.2 [14.7] years; 50.2% female) without a history of psychosis. There were 407 737 individuals with an incident ED visit for substance use, of which 13 784 (3.4%) ED visits were for substance-induced psychosis. Individuals with substance-induced psychosis were at a 163-fold (age- and sex-adjusted hazard ratio [aHR], 163.2; 95% CI, 156.1-170.5) increased risk of transitioning, relative to the general population (3-year risk, 18.5% vs 0.1%). Individuals with an ED visit for substance use without psychosis had a lower relative risk of transitioning (aHR, 9.8; 95% CI, 9.5-10.2; 3-year risk, 1.4%), but incurred more than 3 times the absolute number of transitions (9969 vs 3029). Cannabis use had the highest transition risk among visits with psychosis (aHR, 241.6; 95% CI, 225.5-258.9) and the third-highest risk among visits without psychosis (aHR, 14.3; 95% CI, 13.5-15.2). Younger age and male sex were associated with a higher risk of transition, and the risk of male sex was greater in younger compared with older individuals, particularly for cannabis use.. The findings of this cohort study suggest that ED visits for substance use were associated with an increased risk of developing a schizophrenia spectrum disorder. Although substance-induced psychoses had a greater relative transition risk, substance use without psychosis was far more prevalent and resulted in a greater absolute number of transitions. Several factors were associated with higher transition risk, with implications for counseling and early intervention.

Topics: Adult; Cannabis; Cohort Studies; Emergency Service, Hospital; Female; Hallucinogens; Humans; Male; Ontario; Psychotic Disorders; Retrospective Studies; Schizophrenia; Substance-Related Disorders

The endocannabinoid system has been associated with various psychiatric disorders, such as schizophrenia or addictive disorders. Recent studies have found that some polymorphisms in the cannabinoid receptor type 2 (CNR2), cannabinoid receptor type 1 (CNR1) and fatty acid amide hydrolase (FAAH) genes could play an important role as risk factors in the etiology of these diseases. We analysed different cannabinoid gene polimorphisms from non-substance using patients diagnosed with schizophrenia (n = 379), schizophrenic patients with cannabis use disorders (n = 124), cannabis users who did not have psychoses (n = 71), and 316 controls from various Spanish hospitals and health centres. We found a statistical association between polymorphisms rs35761398 and rs12744386 in the CNR2 gene and comorbidity of schizophrenia and cannabis dependence, as well as an association between loss of heterozygosity (overdominance) for polymorphism rs324420 in the FAAH gene and cannabis dependence in a Spanish population sample. The rs35761398 and rs12744386 polymorphisms in the CNR2 gene are genetic risk factors for schizophrenia in cannabis-dependent subjects. Loss of heterozygosity for polymorphism rs324420 in the FAAH gene is a genetic risk factor for cannabis dependence in this population.. El sistema cannabinoide se ha asociado con varios trastornos psiquiátricos como la esquizofrenia y las adicciones. Diversos estudios han observado que algunos polimorfismos del receptor cannabinoide tipo 2 (CNR2), del receptor cannabinoide tipo 1 (CNR1) y del gen de la enzima amido hidrolasa de ácidos grasos (FAAH) pueden ser factores de riesgo de estos trastornos. Hemos analizado diversos polimorfismos del sistema cannabinoide en pacientes diagnosticados de esquizofrenia sin trastorno por uso de sustancias (n = 379), esquizofrenia con trastorno por uso de cannabis (n = 124), dependientes de cannabis sin psicosis asociada (n = 71) y un grupo de control (316) procedentes de diversos hospitales y centros de asistencia sanitaria españoles. Hemos encontrado una asociación entre los polimorfismos rs35761398 y rs12744386 del CNR2 con la presencia de esquizofrenia y trastorno por uso de cannabis comórbido y una pérdida de heterocigosidad en el polimorfismo rs324420 del gen FAAH con la dependencia de cannabis en población española. Los polimorfismos rs35761398 y rs12744386 en CNR2 son factores de riesgo para esquizofrenia en sujetos dependientes de cannabis. La pérdida de heterocigosidad en el polimorfismo rs324420 en el gen FAAH es un factor de riesgo para la dependencia de cannabis.

Topics: Cannabis; Comorbidity; Humans; Marijuana Abuse; Polymorphism, Single Nucleotide; Receptors, Cannabinoid; Schizophrenia

Topics: Adolescent; Bipolar Disorder; Cannabinoid Receptor Agonists; Cannabis; Electrophysiology; Humans; Mental Disorders; Retina; Schizophrenia

Cognitive deficits are a core feature of schizophrenia, and comorbid substance use may be a contributory factor. Methamphetamine use has been associated with cognitive impairment in schizophrenia, while associations with cannabis use are less clear-cut. This study aimed to investigate the associations of cannabis and methamphetamine use with cognitive performance in first-episode schizophrenia spectrum disorders over the first 2 years of treatment.. This was a longitudinal cohort study in 81 patients treated with flupenthixol decanoate according to a standardized protocol over 24 months. Cognitive performance was assessed with the Measurement and Treatment Research to Improve Cognition in Schizophrenia Cognitive Consensus Battery at four time points, and urine testing for cannabis and methamphetamine was conducted at six time points. We used linear mixed-effect models for repeated measures to assess visit-wise changes in composite cognitive scores in patients (n = 91) compared to matched controls without psychiatric or medical disorders (n = 100). Linear regression models were constructed to examine pre-treatment and end-point effects in patients.. Compared to controls, patients exhibited greater cognitive impairments at baseline, which improved with treatment, but remained significantly lower throughout. The number of positive methamphetamine, but not cannabis, tests predicted less cognitive improvement in patients.. Our findings suggest a negative association between methamphetamine and cognition, but not cannabis.

Topics: Cannabis; Cognition; Humans; Longitudinal Studies; Methamphetamine; Neuropsychological Tests; Psychotic Disorders; Schizophrenia; Schizophrenic Psychology

Confirming the existence and composition of the shared genetic basis of Schizophrenia and cannabis and cigarette smoking has critical values for the clinical prevention and intervention of psychosis.. To achieve this goal, we leveraged Genome-Wide summary statistics of Schizophrenia (n = 99,934), cigarette smoking (n = 518,633) and cannabis usage (n = 162,082). We applied Causal Analysis Using Summary Effect Estimates (CAUSE) and genomic structural equation modeling (GenomicSEM) to quantify the contribution of a common genetic factor of cannabis and cigarette smoking and schizophrenia (referred to as SCZ_SMO), then identified genome-wide loci that made up SCZ_SMO.. Our result provided new evidence on the shared genetic basis model for the association between Schizophrenia and smoking and provided genetic and biological insights into their shared mechanism.

Topics: Cannabis; CD56 Antigen; Cigarette Smoking; Genetic Predisposition to Disease; Genome-Wide Association Study; Humans; Marijuana Abuse; Neurons; Polymorphism, Single Nucleotide; Schizophrenia

Topics: Cannabinoid Receptor Agonists; Cannabis; Hallucinogens; Humans; Marijuana Abuse; Reproducibility of Results; Schizophrenia; Self Report

Psychotic disorder not otherwise specified (PNOS) is considered part of the psychosis spectrum, together with schizophrenia spectrum disorders (SSD) and psychotic bipolar spectrum disorders (PBD). The atypical clinical presentations of PNOS conditions may lead to uncertainty regarding treatment choices and expected outcomes. PNOS is understudied, and little is known about patients' premorbid characteristics including premorbid adjustment, prevalence of early cannabis use and childhood trauma. Knowledge about early illness phases can increase our understanding of this diagnostic group.. We included 1099 participants from the Norwegian TOP-study; 688 with narrow SSD diagnoses (schizophrenia, schizoaffective disorder, schizophreniform disorder), 274 with PBD (psychotic bipolar 1 and bipolar NOS) and 137 with PNOS diagnosed with the SCID-I for DSM-IV. Participants were assessed with the Premorbid Adjustment Scale (PAS) divided into the areas of premorbid academic and social functioning. We obtained information on age at first exposure to cannabis and use of cannabis before the age of 16. The participants also provided information regarding early traumatic experiences using the Childhood Trauma Questionnaire (CTQ).. Participants with PNOS and SSD had poorer premorbid academic functioning than those with PBD (F. Participants with PNOS appear as more similar to participants with SSD than to those with PBD regarding early premorbid adjustment and early cannabis use. The results indicate that many conditions classified as PNOS have functional impairments and problematic substance use from an early age. The prevalence of childhood adversities are high in all three groups.

Topics: Bipolar Disorder; Cannabis; Diagnostic and Statistical Manual of Mental Disorders; Humans; Psychotic Disorders; Schizophrenia; Social Adjustment

Emergency department (ED) visits involving psychosis and schizophrenia have increased at a rate exceeding population growth in the United States over the past decade. Research shows a strong dose-response relationship between chronic use of high-potency cannabis and odds of developing symptoms of psychosis. The aim of this study was to evaluate the impact of cannabis legalization on psychosis and schizophrenia-related ED visits in Colorado.. Using administrative data from Colorado Hospital Association (CHA) on county-level quarterly ED visits between January 1, 2013, and December 31, 2018, we applied a difference-in-difference analysis to examine how new exposure to recreational cannabis dispensaries after 2014 differentially influenced the rate of ED visits for psychosis and schizophrenia, comparing counties with no prior medical cannabis dispensary exposure to counties with low or high medical dispensary exposure.. As recreational dispensaries per 10,000 residents increased, there was no significant association with the rate of schizophrenia ED visits per capita (incidence rate ratio or IRR: 0.95, 95% CI [0.69, 1.30]) while the rate of psychosis visits increased 24% (IRR: 1.24, 95% CI [1.02, 1.49]). Counties with no previous medical dispensaries experienced larger increases in schizophrenia ED visits than counties already exposed to a low level of medical dispensaries, but this effect was not significant. Counties with low baseline medical exposure had lower increases in rates of psychosis visits than counties with high baseline medical exposure (IRR 0.83, 95% CI [0.69, 0.99]).. There was a positive association between the number of cannabis dispensaries and rates of psychosis ED visits across all counties in Colorado. Although it is unclear whether it is access to products, or the types of products that may be driving this association, our findings suggest there is a potential impact on the mental health of the local population that is observed after cannabis legalization.

Topics: Analgesics; Cannabis; Colorado; Hallucinogens; Humans; Patient Acceptance of Health Care; Psychotic Disorders; Schizophrenia; United States

Attention deficits have been considered to be a central characteristic of schizophrenia-spectrum disorders. However, the specific interactions with, and longitudinal effects of, cannabis use at the different stages of the disorder remain unknown. Due to the high percentage of patients who are cannabis users at the onset of the disease, our objective was to explore this relationship and how it evolves in the first three years of the disease.. A total of 461 patients with a first episode of psychosis (FEP) and 187 healthy controls were studied. The differences between cannabis users and non-users at baseline were explored based on both sociodemographic variables and performance in neuropsychological tests of attention. The interaction between cannabis, attentional, and clinical variables was followed up at 3 years.. Of the 648 participants included in this study, 229 (35.34%) were cannabis users. Of them, 187 (40.6%) were patients and 42 (22.5%) were healthy controls. At baseline, control groups [cannabis users (N = 42); non-users (N = 145)] outperformed the patient groups [cannabis users (N = 187); non-users (N = 274)] in all attention tasks. Longitudinal analyses showed significant improvements in the attentional domains at 3-year follow-up, mainly in the group of patients who had never used cannabis (N = 238), followed by ex-users (N = 105), and persistent users (N = 43). At 3-year follow-up, the group of ex-users was the one that achieved scores closer to those of healthy controls.. FEP patients, both cannabis users and non-users, showed attention deficits. However, the patients who had never used cannabis fared better than cannabis users.

Topics: Cannabis; Case-Control Studies; Humans; Neuropsychological Tests; Psychotic Disorders; Schizophrenia

Childhood maltreatment (CM) and genetic vulnerability are both risk factors for psychosis, but the relations between them are not fully understood. Guided by the recent identification of genetic risk to CM, this study investigates the hypothesis that genetic risk to schizophrenia also increases the risk of CM and thus impacts psychosis risk. The relationship between schizophrenia polygenetic risk, CM, and psychotic-like experiences (PLE) was investigated in participants from the Utrecht Cannabis Cohort (N = 1262) and replicated in the independent IMAGEN cohort (N = 1740). Schizophrenia polygenic risk score (SZ-PRS) were calculated from the most recent GWAS. The relationship between CM, PRS, and PLE was first investigated using multivariate linear regression. Next, mediation of CM in the pathway linking SZ-PRS and PLE was examined by structural equation modeling, while adjusting for a set of potential mediators including cannabis use, smoking, and neuroticism. In agreement with previous studies, PLE were strongly associated with SZ-PRS (B = 0.190, p = 0.009) and CM (B = 0.575, p < 0.001). Novel was that CM was also significantly associated with SZ-PRS (B = 0.171, p = 0.001), and substantially mediated the effects of SZ-PRS on PLE (proportion mediated = 29.9%, p = 0.001). In the replication cohort, the analyses yielded similar results, confirming equally strong mediation by CM (proportion mediated = 34.7%, p = 0.009). Our results suggest that CM acts as a mediator in the causal pathway linking SZ-PRS and psychosis risk. These findings open new perspectives on the relations between genetic and environmental risks and warrant further studies into potential interventions to reduce psychosis risk in vulnerable people.

Topics: Cannabis; Child; Child Abuse; Genetic Background; Genetic Predisposition to Disease; Humans; Psychotic Disorders; Schizophrenia; Young Adult

Most studies of the prevalence of cannabis use among patients with schizophrenia used a self-report as declared by the patient himself. We hypothesize that patients with schizophrenia did not tell the truth and might underreport their use for many reasons to be discussed later. Indeed, the under-report of cannabis use among these patients can affect the effectiveness of their treatment.. To assess the degree of agreement between the prevalence values obtained from patients' reports and the results of the toxicological tests.. A cross-sectional study was carried out on 403 patients with schizophrenia. A sociodemographic, psychiatric history and illicit drug use profile was performed for each patient. We assessed the patients with the Positive and Negative Syndrome Scale (PANSS), Calgary Depression score (CDSS), Barratt Impulsiveness Score (BIS-10) and Medication Adherence Rating Scale (MARS). The consumption of cannabis used was confirmed with MINI International Neuropsychiatric Interview (MINI-DSM IV) and using toxicological analysis.. Among the 403 patients who consented to give their urine samples, 49.1% (198/403) tested positive for cannabis, and 41.41% (82/198) underreported their use. The sensitivity and specificity of the questionnaire were 0.58 and 0.74. Based on the comparison between sociodemographic and psychiatric history data of patients who self-report and underreport their cannabis use, no significant difference was observed except for the duration of cannabis use and the score on the medication adherence scale. Moreover, it was found that impulsivity, PANSS score, CDSS score, and the type of schizophrenia are not involved in predicting the underreporting of cannabis use.. The rate of patients who under-report cannabis use is important. Therefore, toxicological analysis is becoming relevant for identifying drug use among schizophrenic patients and in the addictive comorbidity research field.

Topics: African People; Cannabinoid Receptor Agonists; Cannabis; Cross-Sectional Studies; Humans; Psychometrics; Schizophrenia; Schizophrenic Psychology

Topics: Cannabis; Hallucinogens; Humans; Magnetic Resonance Imaging; Marijuana Abuse; Psychotic Disorders; Schizophrenia

This study explored the differences in white matter (WM) microstructural integrity and gray matter (GM) volume between cannabis-induced psychosis (CIP) and schizophrenia with cannabis use (SZC).. This cross-sectional study with convenience sampling involved three groups of 20 participants each (CIP, SZC, and a control group without substance use), matched on age, handedness, and education. CIP and SZC were diagnosed with the Psychiatric Research Interview for Substance and Mental Disorders. Diffusion tensor and kurtosis imaging were done, and fractional anisotropy (FA), mean diffusivity, and mean kurtosis were estimated. GM volume was measured with voxel-based morphometry.. Group comparisons revealed comparable age at initiation and duration and frequency of cannabis use between participants in the SZC and CIP groups. Participants with SZC had lower FA than controls in the anterior and retrolenticular internal capsule limbs, cingulate gyrus hippocampal formation, fornix, and superior fronto-occipital fasciculus (all p<0.05). Participants with CIP had lower FA than controls in the left fornix and right superior fronto-occipital fasciculus but higher FA than those with SZC in the left corticospinal tract (all p<0.05). On morphometry, participants with CIP had greater cerebellar GM volume than those with SZC and greater inferior frontal gyrus volumes than controls (all p<0.05).. Widespread WM microstructural abnormalities were observed in participants with SZC, and fewer but significant WM disruptions were observed in those with CIP. Better WM integrity in some WM fiber tracts and greater GM volumes in crucial brain areas among those with CIP may have prevented the transition to schizophrenia.

Topics: Cannabis; Cross-Sectional Studies; Gray Matter; Humans; Psychotic Disorders; Schizophrenia; White Matter

The nature of the robust association between cannabis use and schizophrenia remains undetermined. Plausible hypotheses explaining this relationship include the premise that cannabis use causes schizophrenia, increased liability for schizophrenia increases the risk of cannabis use initiation (eg, self-medication), or the bidirectional causal hypothesis where both factors play a role in the development of the other. Alternatively, factors that confound the relationship between schizophrenia and cannabis use may explain their association. Externalizing behaviors are related to both schizophrenia and cannabis use and may influence their relationship.. This study aimed to evaluate whether externalizing behaviors influence the genetic relationship between cannabis use and schizophrenia. We conducted a multivariate genome-wide association analysis of 6 externalizing behaviors in order to construct a genetic latent factor of the externalizing spectrum. Genomic structural equation modeling was used to evaluate the influence of externalizing behaviors on the genetic relationship between cannabis use and schizophrenia.. We found that externalizing behaviors partially explained the association between cannabis use and schizophrenia by up to 42%.. This partial explanation of the association by externalizing behaviors suggests that there may be other unidentified confounding factors, alongside a possible direct association between schizophrenia and cannabis use. Future studies should aim to identify further confounding factors to accurately explain the relationship between cannabis use and schizophrenia.

Topics: Cannabis; Genome-Wide Association Study; Humans; Marijuana Abuse; Risk Factors; Schizophrenia

Schizophrenia is frequently accompanied with social cognitive disturbances. Cannabis represents one established environmental factor associated with the onset and progression of schizophrenia. The present cross-sectional study aimed to investigate the association of facial emotion recognition (FER) performance with cannabis use in 2039 patients with schizophrenia, 2141 siblings, and 2049 healthy controls (HC). FER performance was measured using the Degraded Facial Affect Recognition Task (DFAR). Better FER performance as indicated by higher DFAR-total scores was associated with lifetime regular cannabis use in schizophrenia (B = 1.36, 95% CI 0.02 to 2.69), siblings (B = 2.17, 95% CI 0.79 to 3.56), and HC (B = 3.10, 95% CI 1.14 to 5.06). No associations were found between DFAR-total and current cannabis use. Patients with schizophrenia who started to use cannabis after the age of 16 showed better FER performance than patients who started earlier (B = 2.50, 95% CI 0.15 to 4.84) and non-users (B = 3.72, 95 CI 1.96 to 5.49). Better FER performance was found also in siblings who started to use cannabis after 16 compared to non-users (B = 2.37, 95% CI 0.58 to 4.16), while HC using cannabis performed better than non-users at DFAR-total regardless of the age at onset. Our findings suggest that lifetime regular cannabis use may be associated with better FER regardless of the psychosis risk, but that FER might be moderated by age at first use in people with higher genetic risk. Longitudinal studies may clarify whether there is a cause-and-effect relationship between cannabis use and FER performance in psychotic and non-psychotic samples.

Topics: Cannabinoid Receptor Agonists; Cannabis; Cross-Sectional Studies; Emotions; Facial Recognition; Humans; Psychotic Disorders; Schizophrenia; Siblings

We examined group differences in cortical thickness and surface-parameters among age and handedness--matched persons with cannabis-induced psychosis (CIP), schizophrenia with heavy cannabis use (SZC), and healthy controls (HC).. We recruited 31 men with SZC, 28 with CIP, and 30 with HC. We used the Psychiatric Research Interview for Substance and Mental Disorders to differentiate between CIP and SZC. We processed and analyzed T1 MR images using the Surface-based Brain Morphometry (SBM) pipeline of the CAT-12 toolbox within the statistical parametric mapping. After pre-processing, volumes were segmented using surface and thickness estimation for the analysis of the region of interest. We used the projection-based thickness method to assess the cortical thickness and Desikan-Killiany atlas for cortical parcellation.. We observed the lowest cortical thickness, depth, and gyrification in the SZC, followed by CIP and the control groups. The differences were predominantly seen in frontal cortices, with limited parietal and temporal regions involvement. After False Discovery Rate (FDR) corrections and post-hoc analysis, SZC had reduced cortical thickness than HC in the middle and inferior frontal, right entorhinal, and left postcentral regions. Cortical thickness of SZC was also significantly lower than CIP in bilateral postcentral and right middle frontal regions. We found negative correlations (after FDR corrections) between the duration of cannabis use and cortical thickness in loci of parietal and occipital cortices.. Our study suggested cortical structural abnormalities in schizophrenia, in reference to healthy controls and cannabis-induced psychosis, indicating different pathophysiology of SZC and CIP.

Topics: Brain; Cannabis; Cerebral Cortex; Magnetic Resonance Imaging; Marijuana Abuse; Psychotic Disorders; Schizophrenia

Cannabis use disorder is frequent in schizophrenia patients, and it is associated with an earlier age of onset and poor schizophrenia prognosis. Serotonin 2A receptors (5-HT2AR) have been involved in psychosis and, like Akt kinase, are known to be modulated by THC. Likewise, endocannabinoid system dysregulation has been suggested in schizophrenia. The presence of these molecules in blood makes them interesting targets, as they can be evaluated in patients by a minimally invasive technique. The aim of the present study was to evaluate 5-HT2AR protein expression and the Akt functional status in platelet homogenates of subjects diagnosed with schizophrenia, cannabis use disorder, or both conditions, compared with age- and sex-matched control subjects. Additionally, endocannabinoids and pro-inflammatory interleukin-6 (IL-6) levels were also measured in the plasma of these subjects. Results showed that both platelet 5-HT2AR and the active phospho (Ser473)Akt protein expression were significantly increased in schizophrenia subjects, whereas patients with a dual diagnosis of schizophrenia and cannabis use disorder did not show significant changes. Similarly, plasma concentrations of anandamide and other lipid mediators such as PEA and DEA, as well as the pro-inflammatory IL-6, were significantly increased in schizophrenia, but not in dual subjects. Results demonstrate that schizophrenia subjects show different circulating markers pattern depending on the associated diagnosis of cannabis use disorder, supporting the hypothesis that there could be different underlying mechanisms that may explain clinical differences among these groups. Moreover, they provide the first preliminary evidence of peripherally measurable molecules of interest for bigger prospective studies in these subpopulations.

Topics: Biomarkers; Cannabinoid Receptor Agonists; Cannabis; Humans; Interleukin-6; Marijuana Abuse; Prospective Studies; Proto-Oncogene Proteins c-akt; Schizophrenia

It is not clear to what extent associations between schizophrenia, cannabis use and cigarette use are due to a shared genetic etiology. We, therefore, examined whether schizophrenia genetic risk associates with longitudinal patterns of cigarette and cannabis use in adolescence and mediating pathways for any association to inform potential reduction strategies.. Associations between schizophrenia polygenic scores and longitudinal latent classes of cigarette and cannabis use from ages 14 to 19 years were investigated in up to 3925 individuals in the Avon Longitudinal Study of Parents and Children. Mediation models were estimated to assess the potential mediating effects of a range of cognitive, emotional, and behavioral phenotypes.. The schizophrenia polygenic score, based on single nucleotide polymorphisms meeting a training-set. Our study provides evidence that genetic risk for schizophrenia is associated with patterns of cannabis use during adolescence. Investigation of pathways other than the cognitive, emotional, and behavioral phenotypes examined here is required to identify modifiable targets to reduce the public health burden of cannabis use in the population.

Topics: Cannabis; Genetic Predisposition to Disease; Longitudinal Studies; Nicotiana; Risk Factors; Schizophrenia; Tobacco Products

The aim of this study is to evaluate the associations between alcohol-cannabis use and forensic/stressful events with the risk of incident clinical psychosis during follow-up.. A community-based sample (n: 2142) was screened for clinical psychosis (schizophrenia and other psychotic disorders, affective disorders with psychotic features) at baseline and follow-up. Thus, incident clinical psychosis cases to develop during follow-up (individuals with no clinical psychosis at the baseline assessment and with clinical psychosis at the follow-up assessment) were detected (n: 27). These cases and the controls who did not report any psychotic symptoms at the follow-up assessment (n: 1691) were compared for exposure to environmental risk factors during follow-up (total n: 1718).. Individuals reporting heavy alcohol drinking or cannabis use during follow-up had significantly higher risk of incident clinical psychosis. The monthly frequency of drinking and cannabis use was also associated with the risk. Higher number of stressful life events exposed predicted higher risk of incident clinical psychosis. The risk of incident clinical psychosis was significantly higher in case of coexistence of two risk factors (heavy drinking, cannabis use, ≥3 stressful events), in comparison with the existence of a single risk factor (17.7 vs. 1.6%, p<0.001).. Heavy drinking, cannabis use, forensic events and stressful events were associated with the risk of incident clinical psychosis. The coexistence of multiple stressful events and disorders related to abuse of alcohol/cannabis should be considered as a warning for the development of clinical psychosis.

Topics: Cannabis; Humans; Marijuana Abuse; Prospective Studies; Psychotic Disorders; Risk Factors; Schizophrenia

Worldwide, cannabis is the most used illegal substance, and the use of cannabis has increased over the years. An increase in the level of tetrahydrocannabinol (THC) in cannabis has also been seen. It is currently unclear whether this has led to an increase in the incidence of cannabis-induced psychosis. We aimed to investigate (1) the development of incidence of cannabis-induced psychosis over time compared with other substance-induced psychoses and (2) the development of incident cases of cannabis-induced psychosis over time compared with dual diagnosis defined as schizophrenia and a cannabis use disorder.. Data on psychiatric diagnoses were extracted from the Danish Psychiatric Central Research Register and summarized per year as both absolute incidence (number of cases) and incidence rates per 100 000 person years.. The incidence rate of cannabis-induced psychosis increased steadily from 2.8 per 100 000 person years in 2006 to 6.1 per 100 000 person years in 2016. There was a corresponding increase in dual diagnosis with schizophrenia and cannabis use disorder, but a decrease in alcohol-induced psychosis. The data showed no trend in the other substance-induced psychosis investigated in this thesis.. The increase in cannabis-induced psychosis follows both the increase in the level of THC in cannabis, and the increase in cannabis use. The change in diagnostic practice does not appear to explain the increase in incidence of cannabis-induced psychosis.

Topics: Adult; Cannabis; Denmark; Diagnosis, Dual (Psychiatry); Humans; Incidence; Marijuana Abuse; Middle Aged; Psychoses, Substance-Induced; Psychotic Disorders; Schizophrenia; Young Adult

Daily use of high-potency cannabis has been reported to carry a high risk for developing a psychotic disorder. However, the evidence is mixed on whether any pattern of cannabis use is associated with a particular symptomatology in first-episode psychosis (FEP) patients.. We analysed data from 901 FEP patients and 1235 controls recruited across six countries, as part of the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) study. We used item response modelling to estimate two bifactor models, which included general and specific dimensions of psychotic symptoms in patients and psychotic experiences in controls. The associations between these dimensions and cannabis use were evaluated using linear mixed-effects models analyses.. In patients, there was a linear relationship between the positive symptom dimension and the extent of lifetime exposure to cannabis, with daily users of high-potency cannabis having the highest score (. Our findings provide the first large-scale evidence that FEP patients with a history of daily use of high-potency cannabis present with more positive and less negative symptoms, compared with those who never used cannabis or used low-potency types.

Topics: Cannabis; Case-Control Studies; Gene-Environment Interaction; Humans; Marijuana Abuse; Psychotic Disorders; Schizophrenia

Cannabis use is considered an established risk factor for psychosis development. Differentiating between cannabis-induced disorders and schizophrenia is useful for prognostic and therapeutic purposes. Three inpatients groups were differentiated: cannabis-induced psychosis (CIP) (n = 69; mean age = 27.4, SD = 6.5; 82.6% males), schizophrenia with cannabis abuse or dependence (SZ + CB) (n = 57; mean age = 31.9, SD = 10.1; 94.7% males) and schizophrenia without cannabis abuse or dependence (SZ) (n = 181; mean age = 41.8, SD = 13.3; 54.1% males). The Psychiatric Research Interview for Substance and Mental Disorders (PRISM-IV) scale was used to differentiate induced psychosis. The CIP group presented lower mean scores on the negative PANSS subscale (M = 12.9, SD = 5.9; F = 32.24, p < 0.001), fewer auditory hallucinations (60.3%; X² = 6.60, p = 0.037) and greater presence of mania (26.1% vs. 12.3%; X² = 32.58, p < 0.001) than the SZ + CB group. There were few clinical differences between patients with schizophrenia, regardless of previous cannabis use. The age of first admission due to psychosis was lower in both psychotic inpatients groups with cannabis use (M = 26.1, SD = 6.4 in CIP and M = 25.3, SD = 6.2 in SZ + CB; X² = 20.02, p < 0,001). A clinical pattern characteristic of cannabis-induced psychosis was not observed, but the precipitating role of cannabis in the appearance of psychotic symptoms was demonstrated, given the lower age of first admission due to psychosis in cannabis user groups.. El consumo de cannabis se considera un factor de riesgo establecido para el desarrollo de psicosis. Diferenciar los trastornos inducidos por cannabis de la esquizofrenia resulta útil desde el punto de vista pronóstico y terapéutico. Se diferenciaron tres grupos de pacientes hospitalizados: psicosis inducida por cannabis (PIC) (n = 69; Media de edad = 27,4, DE = 6,5; 82,6 % varones), esquizofrenia con abuso o dependencia de cannabis (EZ + CB) (n = 57; Media de edad = 31,9, DE = 10,1; 94,7% varones) y esquizofrenia sin abuso o dependencia de cannabis (EZ) (n = 181; Media de edad = 41,8, DE = 13,3; 54,1% varones). Se utilizó la escala Psychiatric Research Interview for Substance and Mental Disorders (PRISM-IV) para la diferenciación de cuadros inducidos. El grupo PIC presentó puntaciones inferiores en la subescala PANSS negativa (M = 12,9, DE = 5,9; F = 32,24; p < 0,001), menos alucinaciones auditivas (60,3%; X²  = 6,60; p = 0,037) y mayor presencia de manía (26,1% vs. 12,3%; X² = 32,58; p < 0,001) en comparación con el grupo EZ + CB. Hubo pocas diferencias clínicas entre los pacientes con esquizofrenia, independientemente del consumo de cannabis. La edad del primer ingreso por psicosis fue menor en ambos grupos de psicóticos consumidores (M = 26,1, DE = 6,4 en PIC y M = 25,3, DE = 6,2 en EZ + CB; X² = 20,02; p < 0,001). No se observó un patrón clínico característico de las psicosis inducidas por cannabis, aunque sí se demostró el papel precipitante del cannabis en la aparición de psicosis, dada la menor edad de ingreso en los consumidores.

Topics: Adult; Cannabis; Humans; Marijuana Abuse; Psychotic Disorders; Risk Factors; Schizophrenia

To explore the relationship between cannabis use and metabolic syndrome (MetS) among those who have experienced first episode psychosis (FEP).. A retrospective analysis of 404 participants enrolled in the Recovery After Initial Schizophrenia Episode-Early Treatment Program (RAISE-ETP) was conducted. Using multiple logistic regression, we investigated the correlation between cannabis use and rate of MetS at baseline and across time as well as the specific metabolic derangements among cannabis users and abstainers.. Although cannabis users had similar rates of MetS at baseline when compared with abstainers, those who used cannabis at any time during the study period tended to have lower triglycerides and elevated high-density lipoprotein (HDL). Cannabis users were less likely to develop MetS, relative to nonusers.. Cannabis use may be associated with lower incidence of MetS in patients who have experienced FEP. Further research is indicated to develop these observations.

Topics: Cannabis; Humans; Metabolic Syndrome; Psychotic Disorders; Retrospective Studies; Schizophrenia

Cannabis use during adolescence is associated with an increased risk of developing psychosis. According to a current hypothesis, this results from detrimental effects of early cannabis use on brain maturation during this vulnerable period. However, studies investigating the interaction between early cannabis use and brain structural alterations hitherto reported inconclusive findings. We investigated effects of age of cannabis initiation on psychosis using data from the multicentric Personalized Prognostic Tools for Early Psychosis Management (PRONIA) and the Cannabis Induced Psychosis (CIP) studies, yielding a total sample of 102 clinically-relevant cannabis users with recent onset psychosis. GM covariance underlies shared maturational processes. Therefore, we performed source-based morphometry analysis with spatial constraints on structural brain networks showing significant alterations in schizophrenia in a previous multisite study, thus testing associations of these networks with the age of cannabis initiation and with confounding factors. Earlier cannabis initiation was associated with more severe positive symptoms in our cohort. Greater gray matter volume (GMV) in the previously identified cerebellar schizophrenia-related network had a significant association with early cannabis use, independent of several possibly confounding factors. Moreover, GMV in the cerebellar network was associated with lower volume in another network previously associated with schizophrenia, comprising the insula, superior temporal, and inferior frontal gyrus. These findings are in line with previous investigations in healthy cannabis users, and suggest that early initiation of cannabis perturbs the developmental trajectory of certain structural brain networks in a manner imparting risk for psychosis later in life.

Topics: Adolescent; Cannabis; Gray Matter; Humans; Magnetic Resonance Imaging; Psychotic Disorders; Schizophrenia

Both schizophrenia and cannabis use are associated with structural brain changes. The hippocampus is a region of particular interest due to its role in memory and select cognitive functions, impairment of which is a core feature of schizophrenia and has also been observed in substance abuse. This study aimed to explore the effects of recent/current cannabis use on hippocampal subfield volumes in male patients with first-episode schizophrenia spectrum disorders and matched controls.. This cross-sectional, case-control study included 63 patients and 58 controls scanned on 3T MRI scanners, with hippocampal segmentation performed using recently validated Freesurfer v6.0 software. Cannabis use status was determined by self and carer report together with urine toxicology screening, and patients were categorised as recent/current users or non-users. We used multivariate analysis of covariance (MANCOVA) with age, scan sequence, scan quality, and total intracranial volume as covariates, with subsequent analysis of variance (ANOVA) to test the effects of diagnosis and cannabis use status on individual hippocampal subfields.. We found a group (patient/control) by cannabis use interaction effect in the subiculum, with decreased volumes observed in the cannabis non-using patients compared to the cannabis using patients, and decreased volumes in the cannabis using controls compared to the cannabis non-using controls.. The increased subiculum volume in cannabis using patients compared to cannabis non-using patients raises important questions regarding the pathophysiology of schizophrenia and the role of cannabis use therein.

Topics: Cannabis; Case-Control Studies; Cross-Sectional Studies; Hippocampus; Humans; Magnetic Resonance Imaging; Male; Organ Size; Schizophrenia

Cannabis is known to produce acute, transient psychotic-like experiences. However, it is unclear whether cannabis disproportionately increases the risk of specific types of psychotic experiences and whether genetic predisposition influences the relationship between cannabis use and psychotic experiences. In this cross-sectional study of 109,308 UK Biobank participants, we examined how schizophrenia polygenic risk modulates the association between self-reported cannabis use and four types of self-reported psychotic experiences (auditory hallucinations, visual hallucinations, persecutory delusions, and delusions of reference). Cohort-wide, we found a strong, dose-dependent relationship between cannabis use and all four types of psychotic experiences, especially persecutory delusions. Cannabis users' psychotic experiences tended to be earlier-onset and cause greater distress than non-users', but were not more likely to lead to help-seeking. Participants with high schizophrenia polygenic risk scores showed stronger associations between cannabis use and auditory hallucinations, visual hallucinations, and delusions of reference, as well as psychotic experiences overall. For instance, cannabis ever-use was associated with 67% greater adjusted odds of delusions of reference among individuals in the top fifth of polygenic risk, but only 7% greater adjusted odds among the bottom fifth. Our results suggest that cannabis use is a predictive risk factor for psychotic experiences, including early-onset and distressing experiences. Individuals genetically predisposed to schizophrenia may be especially vulnerable to psychotic experiences as a result of using cannabis, supporting a long-postulated hypothesis. This study exemplifies the utility of population-scale biobanks for elucidating gene-by-environment interactions relating substance use to neuropsychiatric outcomes and points to the translational potential of using polygenic risk scores to inform personalized harm reduction interventions.

Topics: Biological Specimen Banks; Cannabis; Cross-Sectional Studies; Delusions; Hallucinations; Humans; Psychotic Disorders; Risk Factors; Schizophrenia; United Kingdom

Cannabis-induced psychosis (CIP) has received little research attention. We compared neurocognitive functions in CIP, Schizophrenia with cannabis use (SZC) and healthy control group (CG).. Twenty age, education, and handedness-matched participants were recruited in each of the three groups. CIP and SZC were diagnosed with Psychiatric research interviews for substance use and mental disorders. Level of cannabis exposure, global intelligence, executive function, attention, vigilance, working, and verbal memory, and motor speed were compared by analysis of variance with post-hoc Scheffe's test. We did a post-hoc power calculation.. Age at initiation, frequency, duration, and preparation of cannabis use did not differ significantly between CIP and SZC. CIP performed significantly better (than SZC) in tests of general cognitive ability or intelligence and attention, perceptual tracking and sequencing. SZC showed significant dysfunctions (than CG) in all parameters of the tests for executive dysfunction, sustained attention, short-term verbal memory and psychomotor functioning. CIP and CG did not differ in any cognitive domains except for non-perseverative errors in the test for executive functioning.. CIP and SZC had different degrees of impairment compared to controls, but on direct comparisons CIP had better general intelligence and attention.KEY POINTSCannabis-induced psychosis (CIP) may have different neurocognitive impairment than Schizophrenia with cannabis use (SZC)CIP performed better in tests for general intelligence and visual attention than SZCSZC had significant impairment in executive function, attention, verbal memory, and psychomotor speed than controlsCompared to controls, CIP performed significantly worse in some domains of executive functionCIP and SZC had different degrees of cognitive impairments as compared to the controls.

Topics: Cannabis; Case-Control Studies; Cross-Sectional Studies; Humans; Psychoses, Substance-Induced; Schizophrenia

While epidemiological studies support a role for heavy, high-potency cannabis use on first-episode psychosis, genetic models of causation suggest reverse causal effects of schizophrenia on cannabis use liability. We estimated the genetic relationship between cannabis use disorder (CUD) and schizophrenia (SCZ) and tested whether liability for CUD is causally associated with increased liability to SCZ while adjusting for tobacco smoking.. This study used summary statistics from published genome-wide association studies (GWAS). We used genomic structural equation modeling, latent causal variable analysis, and multivariable Mendelian randomization to examine genetic relationships between CUD, cannabis ever-use, ever-smoked tobacco regularly, nicotine dependence and SCZ, and to test for a causal relationship between liability to CUD and liability to SCZ.. Genome-wide association studies were published previously as part of international consortia.. Sample sizes of the GWAS summary statistics used in this study ranged from 161 405 to 357 806 individuals of European ancestry.. Genome-wide summary statistics for CUD and SCZ were the primary measurements, while summary statistics for cannabis ever-use, ever-smoked tobacco regularly and nicotine dependence were included as additional variables in the genomic structural equation models and the multivariable Mendelian randomization analyses.. Genetic liability to CUD was significantly associated with SCZ [β = 0.29, 95% confidence interval (CI) = 0.11, 0.46, P = 0.001], even when accounting for cannabis ever-use, ever-smoked tobacco regularly and nicotine dependence as simultaneous predictors. We found mixed evidence of a causal relationship, with the latent causal variable analysis finding no evidence of causality (genetic causality proportion = -0.08, 95% CI = -0.40, 0.23, P = 0.87) but the multivariable Mendelian randomization analyses suggesting a significant, risk-increasing effect of CUD on liability to SCZ (β = 0.10, 95% CI = 0.02, 0.18, P = 0.02), accounting for the additional risk factors (cannabis ever-use, ever-smoked tobacco regularly and nicotine dependence).. Genetic liability for cannabis use disorder appears to be robustly associated with schizophrenia, above and beyond tobacco smoking and cannabis ever-use, with mixed evidence to support a causal relationship between cannabis use disorder and schizophrenia.

Topics: Cannabis; Genome-Wide Association Study; Genomics; Humans; Schizophrenia

Cognitive impairment is among the core features of schizophrenia. In a healthy population, the cognitive deficit is often linked with cannabis abuse, and although the same would be expected in patients with schizophrenia, research has presented contradictory results.. Participants were patients with first-episode schizophrenia (FES) spectrum disorder who had been lifetime cannabis users (. FES patients using cannabis showed less impaired cognitive functioning with the most prominent difference in visual memory compared to FES non-users. However, they differed neither in the clinical assessment of general psychopathology, positive and negative symptoms, nor in medication from the patient's non-users. A comparison of the HC who used cannabis, and those who did not, revealed no sizeable differences in cognitive performance between the groups.. The results delivered supporting evidence for the trend of superior neurocognitive performance in FES patients with a lifetime history of cannabis use compared to non-using patients.

Topics: Cannabis; Cognition; Cognition Disorders; Humans; Marijuana Abuse; Schizophrenia

Cannabis use is associated with an unfavourable course of illness in schizophrenia, although several factors may confound this association. In this longitudinal study, we explored the influence of cannabis use on baseline symptom severity and treatment outcomes in 98 patients with first-episode schizophrenia spectrum disorders treated with a long acting injectable antipsychotic over 24 months. Using mixed models for repeated measures, we compared visit-wise changes in psychopathology, social and occupational functioning and quality of life between recent/current cannabis users (n=45) and non-users (n=53). There were no significant group by time interactions for any of our outcomes, and with the exception of poorer functionality in cannabis users at baseline, no significant differences in these domains at baseline or month 24. Also, remission rates were similar. However, more cannabis users met our operationally defined relapse criteria compared to non-users, and more frequent cannabis use over the course of treatment, as assessed by positive urine toxicology testing, predicted relapse. Our results suggest that cannabis users do not have poorer treatment response than non-users in terms of symptom reduction over the 24 months of treatment. However, dose-related risk of relapse remains with ongoing cannabis use, possibly by directly reducing the threshold for psychotic breakthrough.

Topics: Cannabis; Humans; Longitudinal Studies; Psychotic Disorders; Quality of Life; Schizophrenia

The effects of cannabis use in vulnerable persons with schizophrenia or schizoaffective disorder, continues to be elucidated.. We compared 55 cannabis-only users (Group 1) with 462 non-substance users (Group 2) on measures of length of stay and number of psychiatric hospitalizations with a primary discharge diagnosis of schizophrenia or schizoaffective disorder using the Wilcoxon-Mann-Whitney non-parametric test for non-normal distributions, analysis of variance (ANOVA), and Poisson regression analysis.. Group 1 had a mean length of stay of 6.15. Cannabis use may not be a good predictor of length of stay, once covariates are considered, and mean number of hospitalizations in hospitalized patients with schizophrenia or schizoaffective disorder.

Topics: Cannabis; Hospitalization; Humans; Length of Stay; Patient Discharge; Psychotic Disorders; Schizophrenia

There is high prevalence of cigarette smoking in individuals with first-episode psychosis (FEP) prior to psychosis onset. The purpose of the study was to determine the impact of previous tobacco use with or without cannabis on first psychotic experiences in FEP and the impact of this use on age of onset of symptoms, including prodromes.. Retrospective analyses from the naturalistic, longitudinal, multicentre, "Phenotype-Genotype and Environmental Interaction. Application of a Predictive Model in First Psychotic Episodes (PEPs)" Study. The authors analysed sociodemographic/clinical data of 284 FEP patients and 231 matched healthy controls, and evaluated first psychotic experiences of patients using the Symptom Onset in Schizophrenia Inventory.. FEP patients had significantly higher prevalence of tobacco, cannabis, and cocaine use than controls. The FEP group with tobacco use only prior to onset (N = 56) had more sleep disturbances (42.9% vs 18.8%, P = 0.003) and lower prevalence of negative symptoms, specifically social withdrawal (33.9% vs 58%, P = 0.007) than FEP with no substance use (N = 70), as well as lower prevalence of ideas of reference (80.4% vs 92.4%, P = 0.015), perceptual abnormalities (46.4% vs 67.4%, P = 0.006), hallucinations (55.4% vs 71.5%, P = 0.029), and disorganised thinking (41.1% vs 61.1%, P = 0.010) than FEP group with previous tobacco and cannabis use (N = 144). FEP patients with cannabis and tobacco use had lower age at first prodromal or psychotic symptom (mean = 23.73 years [SD = 5.09]) versus those with tobacco use only (mean = 26.21 [SD = 4.80]) (P = 0.011).. The use of tobacco alone was not related to earlier age of onset of a first psychotic experience, but the clinical profile of FEP patients is different depending on previous tobacco use with or without cannabis.

Topics: Cannabis; Humans; Psychotic Disorders; Retrospective Studies; Schizophrenia; Tobacco Use

Diagnostic categories do not completely reflect the heterogeneous expression of psychosis. Using data from the EU-GEI study, we evaluated the impact of schizophrenia polygenic risk score (SZ-PRS) and patterns of cannabis use on the transdiagnostic expression of psychosis. We analysed first-episode psychosis patients (FEP) and controls, generating transdiagnostic dimensions of psychotic symptoms and experiences using item response bi-factor modelling. Linear regression was used to test the associations between these dimensions and SZ-PRS, as well as the combined effect of SZ-PRS and cannabis use on the dimensions of positive psychotic symptoms and experiences. We found associations between SZ-PRS and (1) both negative (B = 0.18; 95%CI 0.03-0.33) and positive (B = 0.19; 95%CI 0.03-0.35) symptom dimensions in 617 FEP patients, regardless of their categorical diagnosis; and (2) all the psychotic experience dimensions in 979 controls. We did not observe associations between SZ-PRS and the general and affective dimensions in FEP. Daily and current cannabis use were associated with the positive dimensions in FEP (B = 0.31; 95%CI 0.11-0.52) and in controls (B = 0.26; 95%CI 0.06-0.46), over and above SZ-PRS. We provide evidence that genetic liability to schizophrenia and cannabis use map onto transdiagnostic symptom dimensions, supporting the validity and utility of the dimensional representation of psychosis. In our sample, genetic liability to schizophrenia correlated with more severe psychosis presentation, and cannabis use conferred risk to positive symptomatology beyond the genetic risk. Our findings support the hypothesis that psychotic experiences in the general population have similar genetic substrates as clinical disorders.

Topics: Cannabis; Humans; Linear Models; Psychotic Disorders; Risk Factors; Schizophrenia

Schizophrenia (SCZ) is a neurodevelopmental disorder with a high genetic component, but the presence of environmental stressors can be important for its onset and progression. Cannabis use can be a major risk factor for developing SCZ. However, despite the available data on the neurobiological underpinnings of SCZ, there is an important lack of studies in human neuronal tissue and living cells addressing the effects of cannabis in SCZ patients. In this study, we analysed the most relevant bio-macromolecular constituents in olfactory neuroepithelium (ON) cells of healthy controls non-cannabis users, healthy cannabis users, SCZ patients non-cannabis users, and SCZ patients cannabis users using Synchrotron Radiation-Fourier Transform Infrared (SR-FTIR) spectrometry and microscopy. Our results revealed that SCZ patients non-cannabis users, and healthy cannabis users exhibit similar alterations in the macromolecular profile of ON cells, including disruption in lipid composition, increased lipid membrane renewal rate and lipid peroxidation, altered proteins containing more β-sheet structures, and showed an increase in DNA and histone methylation. Notably, these alterations were not observed in SCZ patients who use cannabis regularly. These data suggest a differential effect of cannabis in healthy controls and in SCZ patients in terms of the macromolecular constituents of ON cells.

Topics: Adult; Cannabis; Cells, Cultured; Female; Humans; Lipid Metabolism; Lipids; Male; Marijuana Smoking; Middle Aged; Nasal Mucosa; Proteins; Schizophrenia; Spectroscopy, Fourier Transform Infrared; Synchrotrons; Young Adult

Topics: Cannabis; Dose-Response Relationship, Drug; Humans; Incidence; Legislation, Drug; Marijuana Use; Prevalence; Psychoses, Substance-Induced; Schizophrenia

Topics: Cannabis; Comorbidity; Humans; Marijuana Abuse; Schizophrenia; Schizophrenic Psychology; Stereotyping

To evaluate if cannabis dose recorded as standard joint unit (SJU) consumed before admission and other related factors have an influence on psychiatric inpatient's symptom severity and clinical outcomes.. Cross-sectional study in an acute psychiatric inpatient unit including 106 individuals. Quantity of cannabis was measured as SJU and symptoms severity through the Brief Psychiatric Rating Scale (BPRS). Secondary outcomes (e.g. length of stay) were also assessed. Bivariate analyses and multivariate analyses were performed to determine the effect of SJU consumed before admission on measures of clinical severity.. Point prevalence of cannabis use before admission was 25.5%. Mean BPRS score was 55.8 (SD = 16.1); and 62.9 (SD = 11.1) among cannabis users. A low degree positive correlation between SJU consumed the week before admission and BPRS score (r. The study did not find a correlation between SJU consumed last week and psychiatric severity. On the other hand, individuals with psychotic disorders reported a higher prevalence of cannabis use the week before admission and displayed higher BPRS scores, which points to the need for the development of tailored interventions for high-risk groups. The SJU is a useful quantification tool suitable for further clinical research.

Topics: Antipsychotic Agents; Cannabis; Cross-Sectional Studies; Hospitalization; Humans; Schizophrenia

This study aims to find the prevalence of medication non-compliance among schizophrenia inpatients and to compare the relative risks of medication non-compliance with cannabis use disorders (CUDs) versus without CUDs. In addition, this study also examines the odds of medication non-compliance in schizophrenia inpatients with CUDs.. This is a retrospective cross-sectional analysis of the nationwide inpatient sample. This sample includes 1,030,949 inpatients (age 18 to 65 years) from 2010 to 2014 with primary ICD-9 diagnoses of schizophrenia and other psychotic disorders, that were further sub grouped based on medication non-compliance. CUDs were recognized using the ICD-9 codes.. The prevalence of medication non-compliance was 26% among schizophrenia inpatients. Multivariable analysis revealed that CUD comorbidity was a significant risk factor for medication non-compliance among schizophrenia patients when unadjusted (OR 1.49, 95%CI 1.469-1.503), and association remained significant even after adjusting for covariates (adjusted OR 1.38, 95%CI 1.268-1.489). Comorbid CUD was seen in young adults (18-35 years, 62.4%), males (80.5%), African Americans (54.1%) and low-income families below 25th percentile (48.6%) with personality disorders (10.5%).. Medication compliance is a challenge among schizophrenia patients, which has a significant adverse impact on the course of illness. CUD Comorbidity increases the risk of medication non-compliance significantly among schizophrenia patients. In addition to case management, an integrated treatment model to address both substance use disorders and psychosis will translate into better long-term outcomes in schizophrenia patients.

Topics: Adolescent; Adult; Aged; Cannabis; Comorbidity; Cross-Sectional Studies; Humans; Inpatients; Male; Marijuana Abuse; Medication Adherence; Middle Aged; Retrospective Studies; Schizophrenia; United States; Young Adult

Patients with psychiatric conditions are increasingly using cannabinoids, particularly cannabidiol (CBD), to treat their own symptoms. After reviewing the mechanism of action of CBD, the current article examines the existing evidence for CBD in the treatment of schizophrenia, anxiety, autism, posttraumatic stress disorder, and insomnia, and discusses the challenges in translating these studies, often using very high doses of CBD, into clinical practice. Until additional, well-designed studies that examine the more common practice of lower doses of CBD are performed, a harm-reduction, patient-centered, empiric approach is encouraged to optimize symptom reduction while at the same time avoiding the known risks of cannabis. [Journal of Psychosocial Nursing and Mental Health Services, 57(10), 7-11.].

Topics: Anxiety Disorders; Cannabidiol; Cannabis; Humans; Mental Health; Schizophrenia; Sleep Initiation and Maintenance Disorders; Stress Disorders, Post-Traumatic

Research concerning the spatial orientation in patients with schizophrenia has demonstrated a state independent deficit in inhibition of return (IOR), which has been discussed as a vulnerability marker for schizophrenia. Other recent investigations on brain structure and cognitive processing have revealed less deficits in schizophrenia patients with comorbid cannabis use (SCH + CUD) compared to abstinent schizophrenia patients (SCH). It was hypothesized that these results may reflect a premorbid lower vulnerability in at least a subgroup of comorbid patients. The aim of the present study is to extend previous work by investigating IOR functioning in patients with schizophrenia and cannabis use. This in turn should supplement the existing studies on the vulnerability of this patient group. Therefore, we compared IOR functioning in four groups: 62 patients with schizophrenia and 46 healthy controls, both with and without cannabis use. Participants underwent a covert orienting of attention task (COVAT) with peripheral cues and three stimulus onset asynchronies (SOAs: 200 ms, 400 ms and 800 ms). Both schizophrenia groups displayed delayed IOR with a more pronounced IOR effect in SCH + CUD compared to SCH. In healthy controls, IOR did not seem to be significantly affected by cannabis use. Significant IOR-differences between groups were only seen between SCH patients without cannabis use and both healthy groups at SOA 400 ms. Patterns of cannabis use as well as clinical parameters of psychoses did not affect IOR. Our results may support the hypothesis of IOR as a vulnerability marker for schizophrenia and of a lower biological vulnerability in at least a subgroup of SCH + CUD.

Topics: Adult; Attention; Cannabis; Comorbidity; Female; Humans; Inhibition, Psychological; Male; Marijuana Use; Schizophrenia; Schizophrenic Psychology

Evidence suggests that patients with psychosis who have a history of cannabis use, but currently abstain, demonstrate superior cognitive performance than patients who have never used cannabis. The present study aimed to determine the neurocognitive profiles of patients who are in adolescence or early adulthood, when both illness- and drug-onset typically occur.. Subjects were 24 cannabis-using and 79 cannabis-naïve psychosis patients between 16 and 25 years of age. Patients and controls were administered a neurocognitive battery, indexing estimated pre-morbid intelligence, psychomotor speed, mental flexibility, verbal learning and memory, verbal fluency, sustained attention, motor and mental response, and visuospatial learning and memory.. While healthy controls outperformed both patient groups across most cognitive measures, no significant differences between cannabis-using and cannabis-abstinent patients were evident.. Evidently although there may be a group of patients who are diagnosed with a non-affective psychosis disorder regardless of external factors (i.e. cannabis use), some may instead have their illness precipitated through cannabis use at a young age, presenting with unique cognitive and symptomatic repercussions later in life. These results demonstrate no cognitive differences between cannabis-using patients and abstinent patients at the time of illness-onset, providing partial support for an alternative pathway to schizophrenia through early cannabis use.

Topics: Adolescent; Adult; Age Factors; Attention; Cannabis; Female; Humans; Intelligence; Male; Marijuana Smoking; Memory; Neuropsychological Tests; Psychotic Disorders; Schizophrenia; Schizophrenic Psychology; Young Adult

Data on associations between cannabis use and psychopathology, cognition and functional impairment in schizophrenia spectrum disorders (SSD) is controversial.. To examine the effect of cannabis on psychopathology, cognition and real-world functioning in SSD patients.. Naturalistic cross-sectional study, 123 clinically stable SSD outpatients.. demographic and clinical data, psychometric evaluation: Positive and Negative Syndrome, Hamilton Depression Rating, Clinical Global Impression (CGI), Personal and Social Performance and Screen for Cognitive Impairment in Psychiatry (SCIP) scales. Patients were classified as cannabis user patients (CUP) and non cannabis user patients (NCUP) according to self-report, both lifetime and last year.. chi-square, Student t test, ANOVA (Duncan post hoc), and general linear model analysis for adjusting for antipsychotic doses.. Mean age 40.75, 66.7% male, single (66.7%), prior hospital admissions 2.75, mean length of illness 13.85 years. 53.7% were lifetime cannabis users and 8.9% last year users. Lifetime CUP had more hospitalizations (p = 0.013) at a younger age (p = 0.002), and showed better cognitive functioning globally (CGI-C: p = 0.045) and on working memory and processing speed (SCIP-2: p = 0.039; SCIP-5: p = 0.033) and worse functioning in socially useful activities (p = 0.014) than NCUP. All these differences remained after adjusting for antipsychotic doses. Last year cannabis users had worse mood (Hamilton Depression Rating Scale 9.66 vs. 5.64; p = 0.002), but this difference disappears when adjusting for antipsychotic doses.. Lifetime cannabis use is associated with better working memory and processing speed and worse real-world functioning in the area of socially useful activities in patients with schizophrenia-related disorders. Clinicians should, therefore, be aware of it to provide patient-centred care in their daily clinical practice.

Topics: Adult; Cannabis; Cognition; Cross-Sectional Studies; Female; Humans; Male; Marijuana Abuse; Neuropsychological Tests; Schizophrenia

Topics: Adult; Aggression; Antipsychotic Agents; Asia; Asian People; Cannabis; Female; Humans; Logistic Models; Male; Marijuana Smoking; Odds Ratio; Psychotropic Drugs; Schizophrenia; Surveys and Questionnaires

To examine the long-term (up to 10 years) patterns related to cannabis use in a sample of patients with first episode of psychosis (FEP) and the effect that consumption might have on clinical, functioning, and neurocognition at long-term.. Cannabis use was described in 209 FEP patients. Patients were divided into three groups according to cannabis use: persistent users, ex-users, and never-users. Groups were longitudinally (baseline and 10-year follow-up) compared on clinical, functional, and cognitive variables.. Clinical differences at 10-year follow-up were observed between persistent cannabis users and the other two groups (ex-users and never-users), showing persistent users more severe symptoms (BPRS: x. The use of cannabis could negatively affect the evolution of the psychotic disorder. Perhaps the negative effects caused by cannabis use could be reversed with the cessation of consumption. It is necessary to make an effort in the intervention toward an early withdrawal from the use of cannabis, since this could play an important role in the prognosis of the disease.

Topics: Adult; Cannabis; Case-Control Studies; Cohort Studies; Disease Progression; Female; Follow-Up Studies; Humans; Male; Marijuana Smoking; Neurocognitive Disorders; Prognosis; Psychomotor Performance; Psychotic Disorders; Schizophrenia; Severity of Illness Index; Substance-Related Disorders; Time Factors

Schizophrenia (SZ) and bipolar disorder (BD) are heritable, polygenic disorders with shared clinical and genetic components, suggesting a psychosis continuum. Cannabis use is a well-documented environmental risk factor in psychotic disorders. In the current study, we investigated the relationship between SZ genetic load and cannabis use before illness onset in SZ and BD spectrums. Since frequent early cannabis use (age <18 years) is believed to increase the risk of developing psychosis more than later use, follow-up analyses were conducted comparing early use to later use and no use.. We assigned a SZ-polygenic risk score (PGRS) to each individual in our independent sample (N = 381 SZ spectrum cases, 220 BD spectrum cases and 415 healthy controls), calculated from the results of the Psychiatric Genomics Consortium (PGC) SZ case-control study (N = 81 535). SZ-PGRS in patients who used cannabis weekly to daily in the period before first illness episode was compared with that of those who never or infrequently used cannabis.. Patients with weekly to daily cannabis use before illness onset had the highest SZ-PGRS (p = 0.02, Cohen's d = 0.33). The largest difference was found between patients with daily or weekly cannabis use before illness onset <18 years of age and patients with no or infrequent use of cannabis (p = 0.003, Cohen's d = 0.42).. Our study supports an association between high SZ-PGRS and frequent cannabis use before illness onset in psychosis continuum disorders.

Topics: Adolescent; Adult; Bipolar Disorder; Cannabis; Case-Control Studies; Female; Genetic Predisposition to Disease; Humans; Male; Marijuana Abuse; Multifactorial Inheritance; Norway; Psychiatric Status Rating Scales; Risk Factors; Schizophrenia; Young Adult

The authors investigated the rates of conversion to schizophrenia and bipolar disorder after a substance-induced psychosis, as well as risk factors for conversion.. All patient information was extracted from the Danish Civil Registration System and the Psychiatric Central Research Register. The study population included all persons who received a diagnosis of substance-induced psychosis between 1994 and 2014 (N=6,788); patients were followed until first occurrence of schizophrenia or bipolar disorder or until death, emigration, or August 2014. The Kaplan-Meier method was used to obtain cumulative probabilities for the conversion from a substance-induced psychosis to schizophrenia or bipolar disorder. Cox proportional hazards regression models were used to calculate hazard ratios for all covariates.. Overall, 32.2% (95% CI=29.7-34.9) of patients with a substance-induced psychosis converted to either bipolar or schizophrenia-spectrum disorders. The highest conversion rate was found for cannabis-induced psychosis, with 47.4% (95% CI=42.7-52.3) converting to either schizophrenia or bipolar disorder. Young age was associated with a higher risk of converting to schizophrenia. Self-harm after a substance-induced psychosis was significantly linked to a higher risk of converting to both schizophrenia and bipolar disorder. Half the cases of conversion to schizophrenia occurred within 3.1 years after a substance-induced psychosis, and half the cases of conversion to bipolar disorder occurred within 4.4 years.. Substance-induced psychosis is strongly associated with the development of severe mental illness, and a long follow-up period is needed to identify the majority of cases.

Topics: Adult; Age Factors; Bipolar Disorder; Cannabis; Comorbidity; Denmark; Disease Progression; Female; Humans; Male; Mental Disorders; Middle Aged; Prevalence; Proportional Hazards Models; Psychoses, Substance-Induced; Psychotropic Drugs; Risk Factors; Schizophrenia; Young Adult

Cannabis is associated with increased risk for severe mental illness and is commonly used among individuals with schizophrenia or bipolar disorder. In this study we investigated associations between cannabis use and brain structures among patients with schizophrenia or bipolar disorders. Magnetic resonance imaging scans were obtained for 77 schizophrenia and 55 bipolar patients with a history of cannabis use (defined as lifetime use >10 times during one month or abuse/dependence), and 97 schizophrenia, 85 bipolar disorder patients and 277 healthy controls without any previous cannabis use. Cortical thickness, cortical surface area and subcortical volumes were compared between groups. Both hypothesis-driven region-of-interest analyses from 11 preselected brain regions in each hemisphere and exploratory point-by-point analyses were performed. We tested for diagnostic interactions and controlled for potential confounders. After controlling for confounders such as tobacco use and alcohol use disorders we found reduced cortical thickness in the caudal middle frontal gyrus compared to non-user patients and healthy controls. The findings were not significant when patients with co-morbid alcohol and illicit drug use were excluded from the analyses, but onset of cannabis use before illness onset was associated with cortical thinning in the caudal middle frontal gyrus. To conclude, we found no structural brain changes associated with cannabis use among patients with severe mental illness, but the findings indicate excess cortical thinning among those who use cannabis before illness onset. The present findings support the understanding that cannabis use is associated with limited brain effects in schizophrenia as well as bipolar disorder.

Topics: Adult; Bipolar Disorder; Brain; Cannabis; Cross-Sectional Studies; Female; Humans; Magnetic Resonance Imaging; Male; Marijuana Abuse; Organ Size; Schizophrenia

Topics: Bipolar Disorder; Cannabis; Comorbidity; Humans; Parkinson Disease; Psychotropic Drugs; Schizophrenia

Topics: Cannabidiol; Cannabinoids; Cannabis; Humans; Psychotic Disorders; Schizophrenia

While acute cannabis use stimulates appetite, general population studies suggest that chronic use is associated with reduced risk of obesity and other cardiometabolic risk factors. In this study we investigated changes in body mass index (BMI), fasting blood glucose and lipids, and rates of metabolic syndrome risk factors in cannabis users vs. non-users in 109 minimally treated patients with first-episode schizophrenia, schizophreniform or schizo-affective disorder who were treated according to a standardized treatment regime with depot antipsychotic medication over 12 months. Participants underwent repeated urine toxicology tests for cannabis and those testing positive at any time during the study (n = 40), were compared with those who tested negative at all time points (n = 69). There was a significant group*time interaction effect (p = 0.002) with the cannabis negative group showing a greater increase in BMI than the cannabis positive group, after adjusting for age, sex, methamphetamine use and modal dose of antipsychotic. There were no group*time interaction effects for fasting blood glucose or lipids. Post hoc tests indicated significant increases in fasting blood glucose and triglycerides and a decrease in high-density lipoprotein cholesterol for the cannabis negative group, with no significant changes in the cannabis positive group. Rates of metabolic syndrome did not differ significantly between groups, although more cannabis negative patients had elevated waist-circumference at endpoint (p = 0.003). It may be that chronic cannabis use directly suppresses appetite, thereby preventing weight gain in users. However, other indirect effects such as dietary neglect and smoking may be contributory and could explain our findings.

Topics: Adult; Antipsychotic Agents; Body Mass Index; Cannabis; Fasting; Female; Glucose; Humans; Lipids; Longitudinal Studies; Male; Metabolic Syndrome; Psychotic Disorders; Schizophrenia; Substance-Related Disorders; Waist Circumference; Weight Gain; Young Adult

Previously reported comorbidity between schizophrenia and substance use may be explained by shared underlying risk factors, such as genetic background. The aim of the present longitudinal study was to investigate how a genetic predisposition to schizophrenia was associated with patterns of substance use (cannabis use, smoking, alcohol use) during adolescence (comparing ages 13-16 with 16-20 years).. Using piecewise latent growth curve modelling in a longitudinal adolescent cohort (RADAR-Y study, N = 372), we analyzed the association of polygenic risk scores for schizophrenia (PRS; p-value thresholds (p. High schizophrenia vulnerability was associated with a stronger increase in cannabis use at age 16-20 (PRS thresholds p. In conclusion, our findings support a relation between genetic risk to schizophrenia and prospective cannabis use patterns during adolescence. In contrast, no relation between alcohol and smoking was established.

Topics: Adolescent; Alcohol Drinking; Cannabis; Comorbidity; Female; Genetic Predisposition to Disease; Humans; Longitudinal Studies; Male; Marijuana Smoking; Multifactorial Inheritance; Prospective Studies; Risk Factors; Schizophrenia; Schizophrenic Psychology; Young Adult

Cannabis use is observationally associated with an increased risk of schizophrenia, but whether the relationship is causal is not known. Using a genetic approach, we took 10 independent genetic variants previously identified to associate with cannabis use in 32 330 individuals to determine the nature of the association between cannabis use and risk of schizophrenia. Genetic variants were employed as instruments to recapitulate a randomized controlled trial involving two groups (cannabis users vs nonusers) to estimate the causal effect of cannabis use on risk of schizophrenia in 34 241 cases and 45 604 controls from predominantly European descent. Genetically-derived estimates were compared with a meta-analysis of observational studies reporting ever use of cannabis and risk of schizophrenia or related disorders. Based on the genetic approach, use of cannabis was associated with increased risk of schizophrenia (odds ratio (OR) of schizophrenia for users vs nonusers of cannabis: 1.37; 95% confidence interval (CI), 1.09-1.67; P-value=0.007). The corresponding estimate from observational analysis was 1.43 (95% CI, 1.19-1.67; P-value for heterogeneity =0.76). The genetic markers did not show evidence of pleiotropic effects and accounting for tobacco exposure did not alter the association (OR of schizophrenia for users vs nonusers of cannabis, adjusted for ever vs never smoker: 1.41; 95% CI, 1.09-1.83). This adds to the substantial evidence base that has previously identified cannabis use to associate with increased risk of schizophrenia, by suggesting that the relationship is causal. Such robust evidence may inform public health messages about cannabis use, especially regarding its potential mental health consequences.

Topics: Adult; Cannabis; Case-Control Studies; Female; Genetic Variation; Humans; Male; Marijuana Abuse; Marijuana Smoking; Middle Aged; Polymorphism, Single Nucleotide; Random Allocation; Risk Factors; Schizophrenia; Smokers; White People

The purpose of this study was to evaluate the extent of short-term memory impairment and schizophrenia-like symptoms in heavy and systematic cannabis users and the association between the severity of abuse and the longevity of its persistent symptoms after refraining from such use.. A complete psychiatric examination and a psychometric evaluation were performed in 48 solely cannabis users. Additionally, head hair samples were analyzed and the detected cannabinoids levels were correlated with the psychometric findings.. A total of 33.3% (n = 16) of the total examined cannabis users were currently imprisoned. The years of abuse ranged from 1 to 35 years and the median daily dose was 5.84.4 gr and 4.84.0 gr for prisoners (n = 16) and non prisoners (n = 32), respectively. A total of 39.6% of the users experienced hallucinations (mostly auditory), 54.2% experienced delusions (mostly ideas of reference and persecution), 85.4% had organic brain dysfunction in a test addressing visual-motor functioning and visual perception skills, and all users (100%) were found to have organic brain dysfunction in a test of visual memory immediate recall. The cannabinoid metabolite levels in the hair samples were consistent with the reported history of substance abuse and total grams of consumption for the participants below 35 years old (p < .001). Statistically elevated cannabinoids levels were observed in users with auditory hallucinations compared to users without any hallucinations (p = .019).. The existence of hallucinations, delusions, and organic brain dysfunction in heavy cannabis users seems to be associated with cannabinoid levels in hair. The continuation of persistent symptoms 3 months after the discontinuation of cannabis abuse, was a remarkable finding.. We provide evidence that chronic and heavy cannabis abuse results in long-lasting brain dysfunction in all users and in long-lasting schizophrenia-like psychotic symptoms in more than half of all users. These findings suggest a reevaluation of the current classification of cannabis as a "soft narcotic" which erroneously, therefore, is typically considered harmless. (Am J Addict 2017;26:335-342).

Topics: Adult; Cannabinoids; Cannabis; Female; Hair; Humans; Male; Marijuana Abuse; Memory, Short-Term; Schizophrenia; Time; Time Factors; Young Adult

Cannabis use represents a major public health issue throughout the globe. Yet, we still lack the most fundamental knowledge on long-term effects of cannabis on neural, cognitive, and behavioral function. Part of this stems from how cannabis has been measured historically. To this end, most empirical examinations of cannabis have consolidated all types of cannabis collectively. However, this approach obscures differences in how cannabinoids operate. In this commentary, we address the contrasting properties of tetrahydrocannabinol (THC) and cannabidiol (CBD) and their opposing effects on cognitive function. In addition, we address the increase in cannabis potency throughout the past two decades and how that impacts generalizability of early data to evaluations of contemporary public health. We underscore the urgent need for future research to disaggregate examination of THC from CBD, along with the importance of measuring cannabis potency to more effectively unravel its influence on cognitive function and other health issues.

Topics: Brain; Cannabidiol; Cannabis; Cognition; Dronabinol; Humans; Schizophrenia

Topics: Bipolar Disorder; Cannabis; Denmark; Depressive Disorder; Humans; Personality Disorders; Prospective Studies; Schizophrenia; Substance-Related Disorders; Suicide, Attempted

Topics: Cannabis; Humans; Marijuana Smoking; Psychotic Disorders; Schizophrenia

Topics: Cannabis; Electroencephalography; Humans; Schizophrenia; Schizophrenic Psychology

Chronic cannabis use may cause neurocognitive deficits and increase the risk of psychosis. Nevertheless, the effects of cannabis use on neurocognitive functioning in schizophrenia have remained largely unspecified.. Here, we studied repetition suppression of auditory event-related responses in a paired-stimulus design in a mixed sample of schizophrenia patients (n = 34) and healthy control subjects (n = 45) with chronic heavy cannabis use and schizophrenia patients (n = 33) and healthy control subjects (n = 61) without cannabis use.. Repeated measures analysis yielded an overall significant reduction of P50 amplitude between first and second stimulus (p < .02), which was not different between the groups, a reduction of N100 amplitude, which was different for schizophrenia patients compared with healthy control subjects independent of cannabis use (p < .02), and a significant interaction between diagnosis and chronic cannabis use on the reduction of the P200 amplitude (p < .001). While chronic cannabis use was related with increased P200 suppression ratios in control subjects (with chronic cannabis use: 0.55 ± 0.04; without chronic cannabis use: 0.40 ± 0.03; p < .02), the reverse effect was found in schizophrenia (with chronic cannabis use: 0.36 ± 0.05; without chronic cannabis use: 0.54 ± 0.05; p < .02). This result remained significant after inclusion of potential confounders. Total lifetime cannabis use showed a significant correlation with the P200 suppression ratio in otherwise healthy control subjects (r = .28, p < .007). By contrast, the duration of time since last cannabis use was significantly correlated with the P200 suppression ratio in schizophrenia patients (r = .42, p < .002).. In aggregate, these diverging effects of chronic cannabis use on P200 repetition suppression may suggest underlying alterations in the endocannabinoid system in schizophrenia.

Topics: Acoustic Stimulation; Cannabis; Electroencephalography; Evoked Potentials, Auditory; Healthy Volunteers; Humans; Male; Marijuana Abuse; Marijuana Smoking; Schizophrenia; Sensory Gating; Young Adult

Long-term cannabis use may confer cognitive deficits and increased risk of psychosis. However, the relationship between cannabis use and schizophrenia is complex. In particular, little is known about the effects of chronic cannabis use on the attention-related electric brain response in schizophrenia. We investigated auditory novelty and oddball P300 evoked potentials in a mixed sample of first-episode and chronic schizophrenic patients and healthy controls with (SZCA, n = 20; COCA, n = 20, abstinence ≥28 days) or without (SZ, n = 20; CO, n = 20) chronic cannabis use. Duration of regular cannabis use was 8.3 ± 5.6 (SZCA) and 9.1 ± 7.1 (COCA) years. In general, schizophrenic patients showed reduced P300 amplitudes. Cannabis use was associated with both a reduced early and late left-hemispheric novelty P300. There was a significant 'diagnosis × cannabis' interaction for the left-hemispheric late novelty P300 in that cannabis use was associated with a reduced amplitude in the otherwise healthy but not in the schizophrenic group compared with their relative control groups (corrected p < 0.02; p > 0.9, respectively). The left-hemispheric late novelty P300 in the otherwise healthy cannabis group correlated inversely with amount and duration of cannabis use (r = -0.50, p = 0.024; r = -0.57, p = 0.009, respectively). Our study confirms attentional deficits with chronic cannabis use. However, cannabis use may lead to different cognitive sequelae in patients with schizophrenia and in healthy controls, possibly reflecting preexisting alterations in the endocannabinoid system in schizophrenia.

Topics: Adolescent; Adult; Analysis of Variance; Attention Deficit Disorder with Hyperactivity; Cannabis; Electroencephalography; Event-Related Potentials, P300; Female; Humans; Male; Marijuana Abuse; Middle Aged; Psychiatric Status Rating Scales; Schizophrenia; Substance Withdrawal Syndrome; Young Adult

The use of cannabis with higher Δ9-tetrahydrocannabinol content has been associated with greater risk, and earlier onset, of psychosis. However, the effect of cannabis potency on brain morphology has never been explored. Here, we investigated whether cannabis potency and pattern of use are associated with changes in corpus callosum (CC) microstructural organization, in patients with first-episode psychosis (FEP) and individuals without psychosis, cannabis users and non-users.. The CC of 56 FEP (37 cannabis users) and 43 individuals without psychosis (22 cannabis users) was virtually dissected and segmented using diffusion tensor imaging tractography. The diffusion index of fractional anisotropy, mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity was calculated for each segment.. Across the whole sample, users of high-potency cannabis had higher total CC MD and higher total CC AD than both low-potency users and those who never used (p = 0.005 and p = 0.004, respectively). Daily users also had higher total CC MD and higher total CC AD than both occasional users and those who never used (p = 0.001 and p < 0.001, respectively). However, there was no effect of group (patient/individuals without psychosis) or group x potency interaction for either potency or frequency of use. The within-group analysis showed in fact that the effects of potency and frequency were similar in FEP users and in users without psychosis.. Frequent use of high-potency cannabis is associated with disturbed callosal microstructural organization in individuals with and without psychosis. Since high-potency preparations are now replacing traditional herbal drugs in many European countries, raising awareness about the risks of high-potency cannabis is crucial.

Topics: Adolescent; Adult; Affective Disorders, Psychotic; Anisotropy; Cannabis; Case-Control Studies; Comorbidity; Corpus Callosum; Diffusion Tensor Imaging; Female; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Marijuana Smoking; Psychotic Disorders; Schizophrenia; Young Adult

Patients with schizophrenia spectrum disorders and substance use may have an earlier onset of illness compared to those without substance use. Most previous studies have, however, too small samples to control for confounding variables and the effect of specific types of substances. The present study aimed to examine the relationship between substance use and age at onset, in addition to the influence of possible confounders and specific substances, in a large and heterogeneous multisite sample of patients with schizophrenia spectrum disorders.. The patients (N=1119) were recruited from catchment areas in Oslo, Stavanger and Bergen, Norway, diagnosed according to DSM-IV and screened for substance use history. Linear regression analysis was used to examine the relationship between substance use and age at onset of illness.. Patients with substance use (n=627) had about 3years earlier age at onset (23.0years; SD 7.1) than the abstinent group (n=492; 25.9years; SD 9.7). Only cannabis use was statistically significantly related to earlier age at onset. Gender or family history of psychosis did not influence the results.. Cannabis use is associated with 3years earlier onset of psychosis.

Topics: Adult; Age of Onset; Cannabis; Family; Female; Humans; Male; Marijuana Abuse; Norway; Psychotic Disorders; Regression Analysis; Schizophrenia; Sex Factors; Young Adult

Prior cannabis use, compared to nonuse, is reported to be associated with less cognitive impairment in schizophrenia. The age of cannabis use and the persistent influence of cannabis use on cognitive function has not been examined across the psychosis dimension. Ninety-seven volunteers with psychosis (schizophrenia, schizoaffective, or bipolar psychosis) and 64 controls were recruited at the Dallas site of the Bipolar-Schizophrenia Network on Intermediate Phenotypes consortium. Cannabis use history obtained in a semi-structured manner was used to categorize subjects into nonusers, adolescent-onset users, and late-onset users. The a priori hypothesis tested was that individuals with psychosis and a history of adolescent cannabis use (ACU) would have better global neuropsychological performance, as measured by the Brief Assessment of Cognition in Schizophrenia (BACS) battery, compared to those with psychosis and no cannabis use history. BACS Composite scores were significantly higher in individuals with psychosis with ACU compared to individuals with psychosis and no prior cannabis use. In subgroup analyses, ACU influenced global cognition in the schizophrenia/schizoaffective (SCZ) subgroup but not the bipolar psychosis subgroup. Exploratory analyses within the SCZ group, suggest that ACU was associated with better performance in specific domains compared to non-ACU groups. There are distinct associations between age of cannabis use and neuropsychological function across psychotic illnesses. Specifically, ACU is associated with better cognitive function in SCZ but not bipolar psychosis. This age-dependent and diagnosis-specific influence of cannabis may need to be factored into the design of future cognitive studies in SCZ.

Topics: Adolescent; Adolescent Behavior; Adult; Affective Disorders, Psychotic; Cannabis; Cognitive Dysfunction; Female; Humans; Male; Middle Aged; Neuroprotective Agents; Psychotic Disorders; Schizophrenia

We report a case of delirium with anticholinergic symptoms in a 19-year-old female patient with schizophrenia. On the day the symptoms emerged, the patient received olanzapine long-acting injection and a higher dose of paliperidone. We observed symptoms ranging from confusion to delirium as well as some anticholinergic symptoms. The delirium lasted 24 hours and was managed by intravenous fluid substitution and oral benzodiazepines. Olanzapine pamoate, paliperidone and cannabis are central nervous system (CNS) depressants, and their combination can increase the risks of CNS depression. In this case report, we review the symptoms of delirium in a case of antipsychotic overdose and provide general guidelines for managing these symptoms. We also review possible complications in combined use of cannabis, olanzapine and paliperidone.

Topics: Antipsychotic Agents; Benzodiazepines; Cannabis; Central Nervous System; Cholinergic Antagonists; Delirium; Drug Overdose; Female; Humans; Olanzapine; Paliperidone Palmitate; Schizophrenia; Treatment Outcome; Young Adult

Topics: Adult; Cannabis; Child; Cognitive Behavioral Therapy; Conduct Disorder; Depression; Humans; Marijuana Abuse; Randomized Controlled Trials as Topic; Schizophrenia; Suicide Prevention; Telemedicine

Topics: Antipsychotic Agents; Brain; Cannabidiol; Cannabis; Cerebral Cortex; Gene-Environment Interaction; Humans; Marijuana Abuse; Risk Factors; Schizophrenia; Schizophrenic Psychology; Treatment Outcome

Topics: Cannabidiol; Cannabis; Causality; Dronabinol; Humans; Marijuana Abuse; Psychoses, Substance-Induced; Risk Factors; Schizophrenia; Schizophrenic Psychology

The association between cannabinoids and psychosis has been known for almost a thousand years, but it is still speculated whether cannabis use may be a contributory cause of psychosis, that is, whether it may precipitate schizophrenia in those at risk. In this paper, we will briefly present the data from individual longitudinal studies in the field, together with the factors that are considered important for the association of cannabis abuse and occurrence of schizophrenia and prevention opportunities in the target population. The reviewed studies clearly suggest that cannabis abuse predicts an increased risk for schizophrenia, particularly in young adults. They underline both the need to create adequate prevention measures and consequently avoid the occurrence of the disease in the young at risk. Particular attention should be additionally devoted toward encouraging the young presenting with psychotic symptoms to stop or, at the very least, reduce the frequency of cannabis abuse. The issues are undoubtedly to be addressed by the health care system in general.

Topics: Adult; Age of Onset; Biomedical Research; Cannabis; Health Services Needs and Demand; Humans; Longitudinal Studies; Marijuana Abuse; Psychotic Disorders; Risk Assessment; Risk Factors; Schizophrenia; Young Adult

Schizophrenia is a neuropsychiatric disorder in which abnormalities in the prefrontal cortex lead to impaired synthesis of dopamine. It is associated with hallucination, psychosis and hearing impairments. Many susceptible genes have been identified in schizophrenia such as catechol-O-methyltransferase (COMT) and serine/threonine kinase (AKT1). Single nucleotide polymorphisms (SNPs) in these genes have not been identified in Pakistan. Therefore, we investigated the allelic and genotypic frequencies in COMT and AKT1 genes in the Pakistani population. Polymerase chain reactionrestriction fragment length polymorphism (PCR-RFLP) and DNA sequencing were used to identify SNPs in the genes. The present study shows that COMT Val and COMT Met allelic frequencies for the controls were p=0.52, q=0.48 and for the schizophrenic cases they were p=0.34, q=0.66 respectively. The distribution of polymorphism in COMT Val158Met genotype by Hardy-Weinberg equilibrium (HWE) was P=0.61 for controls and P=0.005 for cases. The data reveal that SNP rs1130214 T allele mutation was found neither in patients nor in controls in the 5' untranslated region (UTR). This proves that no association of AKT1 and positive association of COMT with schizophrenia exist in the population of Pakistan. Moreover, a study based on a single family showed COMT Met allele inheritance in schizophrenic offspring. This suggested that COMT allele alteration influences susceptibility to at least some forms of psychosis in the Pakistani population. Interestingly, according to our socio-economical survey, COMT genotype has no association with cannabis but it is strongly associated with tobacco. The Pakistani population with Val158Met SNP showed more susceptibility towards developing schizophrenia. This study highlights the genetic differences between Pakistani and other Caucasian populations.

Topics: Adolescent; Adult; Cannabis; Case-Control Studies; Catechol O-Methyltransferase; Child; Female; Genetic Predisposition to Disease; Humans; Male; Marijuana Smoking; Middle Aged; Pakistan; Polymorphism, Single Nucleotide; Prevalence; Proto-Oncogene Proteins c-akt; Schizophrenia; Substance-Related Disorders; Tobacco Use; Tobacco, Smokeless; Young Adult

Topics: Cannabidiol; Cannabis; Dronabinol; Humans; Marijuana Abuse; Psychoses, Substance-Induced; Schizophrenia; Schizophrenic Psychology

Both cannabis use and the dopamine receptor (DRD2) gene have been associated with schizophrenia, psychosis-like experiences, and cognition. However, there are no published data investigating whether genetically determined variation in DRD2 dopaminergic signaling might play a role in individual susceptibility to cannabis-associated psychosis. We genotyped (1) a case-control study of 272 patients with their first episode of psychosis and 234 controls, and also from (2) a sample of 252 healthy subjects, for functional variation in DRD2, rs1076560. Data on history of cannabis use were collected on all the studied subjects by administering the Cannabis Experience Questionnaire. In the healthy subjects' sample, we also collected data on schizotypy and cognitive performance using the Schizotypal Personality Questionnaire and the N-back working memory task. In the case-control study, we found a significant interaction between the rs1076560 DRD2 genotype and cannabis use in influencing the likelihood of a psychotic disorder. Among cannabis users, carriers of the DRD2, rs1076560, T allele showed a 3-fold increased probability to suffer a psychotic disorder compared with GG carriers (OR = 3.07; 95% confidence interval [CI]: 1.22-7.63). Among daily users, T carrying subjects showed a 5-fold increase in the odds of psychosis compared to GG carriers (OR = 4.82; 95% CI: 1.39-16.71). Among the healthy subjects, T carrying cannabis users had increased schizotypy compared with T carrying cannabis-naïve subjects, GG cannabis users, and GG cannabis-naïve subjects (all P ≤ .025). T carrying cannabis users had reduced working memory accuracy compared with the other groups (all P ≤ .008). Thus, variation of the DRD2, rs1076560, genotype may modulate the psychosis-inducing effect of cannabis use.

Topics: Adolescent; Adult; Cannabis; Case-Control Studies; Disease Susceptibility; Female; Gene-Environment Interaction; Humans; Male; Memory, Short-Term; Middle Aged; Psychoses, Substance-Induced; Receptors, Dopamine D2; Risk; Schizophrenia; Schizotypal Personality Disorder; Young Adult

The mechanism underneath the relationship between cannabis and psychosis remains controversial, for which several hypotheses have been proposed, including cannabis as self-medication and cannabis as a risk for the development of psychosis. The aim of this work was to study the relationship between cannabis and psychosis in first-episode psychosis cannabis users and non-users, and non-psychotic cannabis users. The age at the first psychotic episode, duration of untreated psychosis, psychopathology and reasons for cannabis use were assessed. First-episode psychosis cannabis users showed an earlier age at psychosis onset than non-user patients. No significant differences in symptomatology were found. The distinguishing reasons to use cannabis for patients with first-episode psychosis with respect to non-psychotic users were to arrange their thoughts and deal with hallucinations and suspiciousness. These findings are in agreement with both hypotheses: self-medication and secondary psychosis hypothesis. However, longitudinal prospective cohort studies assessing reasons for cannabis use are needed to investigate both hypotheses and their complementarity.

Topics: Adolescent; Adult; Age Factors; Cannabis; Cross-Sectional Studies; Female; Hallucinations; Humans; Male; Marijuana Abuse; Prospective Studies; Psychopathology; Psychotic Disorders; Risk Factors; Schizophrenia; Schizophrenic Psychology; Self Medication; Surveys and Questionnaires; Young Adult

We aimed to examine the association between lifetime cannabis use and estimates of both premorbid and current cognitive function in psychotic disorders in an Australian cohort.. In an Australian multicenter cohort, 1237 participants with an established ICD-10 diagnosis of psychotic disorder were categorised according to history of lifetime cannabis use (non-users, n=354; cannabis users, n=221; cannabis dependency, n=662). Groups were analyzed according to available indices of cognitive ability: the National Adult Reading Test - Revised (NART-R) for ability prior to illness onset; and the Digit Symbol Coding Test (DSCT) for current ability. Two-way analysis of variance was conducted without any covariate, followed by a two-way analysis of covariance (using age, age at onset of psychiatric illness, premorbid IQ and the Socio-Economic Index for Areas (SEIFA) rankings).. Whilst there appeared to be a significant association between cannabis use and mean DSCT (higher DSCT scores in cannabis using groups) F(2,1080)=9.478, p<0.001, η2=0.017), once covariates were used in the analysis there were no significant differences between groups in mean DSCT scores (F(2,1011)=0.929, p=0.395, η2=0.002). Similarly there were no differences between groups in mean NART scores once, age, age at illness onset and SEIFA rankings were used as covariates (F(2,1032)=1.617, p=0.199, η2=0.003).. Confounding variables underpin the association between cannabis use and cognitive function in psychotic disorders. Taken together, it would appear that cannabis use or dependence has no additive effect on cognitive dysfunction in these disorders.

Topics: Adult; Australia; Cannabis; Cognition; Cognition Disorders; Cohort Studies; Female; Humans; Intelligence; Intelligence Tests; Male; Marijuana Abuse; Marijuana Smoking; Psychological Tests; Psychotic Disorders; Schizophrenia; Schizophrenic Psychology

Topics: Adolescent; Appetite; Biomedical Research; Cannabis; Child; Colorado; Confounding Factors, Epidemiologic; Dronabinol; Humans; Marijuana Abuse; Marijuana Smoking; Medical Marijuana; Multiple Sclerosis; Netherlands; New Zealand; Prevalence; Schizophrenia; Seizures; Sweden; Young Adult

Topics: Cannabis; Cohort Studies; Humans; Marijuana Abuse; Marijuana Smoking; Psychoses, Substance-Induced; Psychotic Disorders; Risk Factors; Schizophrenia; Smoking; Smoking Cessation; Substance-Related Disorders; Surveys and Questionnaires

Topics: Cannabinoids; Cannabis; Humans; Marijuana Abuse; Psychoses, Substance-Induced; Psychotic Disorders; Risk Factors; Schizophrenia

Topics: Cannabinoids; Cannabis; Humans; Marijuana Abuse; Psychoses, Substance-Induced; Psychotic Disorders; Risk Factors; Schizophrenia

Topics: Cannabinoids; Cannabis; Humans; Marijuana Abuse; Psychoses, Substance-Induced; Psychotic Disorders; Risk Factors; Schizophrenia

Topics: Cannabis; Disease Progression; Dronabinol; Humans; Mental Health; Pharmacogenetics; Risk; Schizophrenia

Topics: Cannabis; Humans; Schizophrenia

Cannabis use is associated with the development of psychotic symptoms and increased risk for schizophrenia. The mismatch negativity (MMN) is a brain event-related potential marker of change detection thought to index glutamatergic N-methyl-D-aspartate receptor-mediated neurotransmission, which is known to be deficient in schizophrenia. This study examined auditory MMN in otherwise healthy chronic cannabis users compared with nonuser control subjects.. Forty-two chronic cannabis users and 44 nonuser healthy control subjects completed a multi-feature MMN paradigm, which included duration, frequency, and intensity deviants (deviants 6%; standards 82%). The MMN was compared between users and control subjects as well as between long- and short-term users and age- and gender-matched control subjects. Associations between MMN, cannabis use measures, and symptoms were examined.. The MMN amplitude was significantly reduced to frequency but not duration or intensity deviants in overall cannabis users relative to control subjects. Frequency MMN was similarly attenuated in short- and long-term users relative to control subjects. Long-term users also exhibited reduced duration MMN relative to control subjects and short-term users and this was correlated with increased duration of exposure to cannabis and increased psychotic-like experiences during intoxication. In short-term users, a younger age of onset of regular cannabis use and greater frequency of use were associated with greater psychotic-like experiences and symptomatic distress.. These results suggest impaired sensory memory that might reflect N-methyl-D-aspartate receptor dysfunction in chronic cannabis users. The pattern of MMN alterations in cannabis users differed from that typically observed in patients with schizophrenia, indicating overlapping but distinct underlying pathology.

Topics: Adolescent; Adult; Cannabis; Case-Control Studies; Chronic Disease; Evoked Potentials, Auditory; Female; Humans; Male; Marijuana Abuse; Middle Aged; Receptors, N-Methyl-D-Aspartate; Schizophrenia; Symptom Assessment; Synaptic Transmission; Time Factors; Young Adult

Deficits in incentive motivation are often present in both Schizophrenia Spectrum Disorders (SSD) and substance-use disorders. The current study aims to test whether the presence of such deficits confers vulnerability to cannabis use in individuals with SSD. SSD patients (n=35) and healthy controls (n=35) were each divided into a group with (n=20) and a group without (n=15) current cannabis use disorder. Subjects performed a behavioural task designed for schizophrenia patients in which they could seek exposure to pleasant and cannabis visual stimuli on the basis of internal representations of these stimuli. Intensity of cannabis use was assessed by self-report. SSD patients were significantly less likely than controls to exert effort to try to re-view pleasant stimuli but were not significantly less likely to work to avoid unpleasant stimuli. Lack of response to re-view pleasant stimuli significantly predicted higher subsequent cannabis self-administration in patients but not controls, after controlling for degree of prior exposure to cannabis. Deficits in incentive motivation may be an aspect of SSD which promotes cannabis use in this population.

Topics: Adult; Cannabinoids; Cannabis; Case-Control Studies; Cues; Emotions; Female; Humans; Male; Marijuana Abuse; Marijuana Smoking; Motivation; Reward; Schizophrenia; Schizophrenic Psychology

An earlier age of onset of schizophrenia has been identified as a poor prognostic indicator. The current study examines the interaction effect of gender and cannabis use on age of onset of schizophrenia and schizoaffective disorder. This research forms part of a two-centre epidemiological study of first-episode psychosis and included individuals with a diagnosis of schizophrenia or schizoaffective disorder and an age of onset between age 16 and 45. Kaplan-Meier curves and Cox proportional hazards regression were used to compare the effects of cannabis use and gender on age of first symptom of schizophrenia. Akaike's information criteria were used to find the model with the best fit to the data. Cannabis users had an earlier age of first symptom than non-users. There was an interaction with gender; the gender difference in age of onset was diminished in cannabis smokers compared with non-cannabis smokers. The model including cannabis use interacting with gender was the most parsimonious model, followed by cannabis use alone. The addition of other illegal drug use did not improve the model. Cannabis use is associated with an earlier age of onset of schizophrenia, and the gender difference in age of onset is reduced among cannabis smokers.

Topics: Adolescent; Adult; Age of Onset; Cannabinoids; Cannabis; Female; Humans; Kaplan-Meier Estimate; Male; Marijuana Smoking; Middle Aged; Proportional Hazards Models; Psychotic Disorders; Regression Analysis; Schizophrenia; Sex Factors

Topics: Adolescent; Animals; Brain; Cannabis; Humans; Marijuana Abuse; Risk Factors; Schizophrenia

Based on the previous findings, it has been assumed that in schizophrenia patients, eye dominance and cannabis use will affect negative symptoms and intermanual coordination (IMC), an index of interhemispheric communication. But eye dominance, specifically the clinical findings for it, has been neglected in schizophrenia research. We therefore investigated its effects in 52 right-handed (36 right-eyed and 16 left-eyed) and 51 left-handed (35 left-eyed and 16 right-eyed) schizophrenia in-patients without and with drug use. Eye dominance affected IMC in all schizophrenia patients. When comparing right- and left-handers, we found that this result was only significant in the right-handed patients and in the smaller subgroup without drug use. In the right-handers, left eye dominance-like left-handedness-was associated with higher values in IMC and less pronounced manifestation of negative symptoms, right eye dominance was not. Thus, left-eyed right-handers may be more closely related to left-handers than to right-handers. In accordance with the results from the literature, we suggest that these findings are due to better interhemispheric connections and less impairment of white matter structures, especially in right-hemispheric regions. Moreover, cannabis use was related to higher scores in IMC and less pronounced negative symptoms, but only in the right-eyed and not in the left-eyed right-handers or in the left-handers. Hence, differences in eye dominance and handedness may be partially responsible for different results in interhemispheric connections among cannabis users. In conclusion, both eye dominance and use of cannabis should be taken into account when assessing clinical symptoms in schizophrenia patients.

Topics: Adolescent; Adult; Cannabis; Cerebrum; Dominance, Ocular; Female; Functional Laterality; Humans; Male; Middle Aged; Psychomotor Performance; Schizophrenia; Young Adult

We aimed to examine the association between illicit substance use and age at onset in psychotic disorders in an Australian cohort.. Retrospectively acquired information on substance use during the year prior to illness onset was collected from 1642 participants enrolled in the Australian National 2010 Survey of High Impact Psychosis study (SHIP), with an ICD-10 diagnosis of schizophrenia spectrum or affective psychosis. Latent class analysis was performed according to illicit substance use, using age as an active covariate; identified classes were subsequently validated. Cox regression was used to examine the independent contribution of the identified substance use classes and several confounding variables to the prediction of age at onset of psychosis.. Three classes according to substance use were identified: non-users (n=803), cannabis predominant users (n=582), and polysubstance users (n=257). For participants with schizophrenia spectrum disorders, cannabis predominant users had a higher hazard of earlier age at onset than for non-users (adjusted HR=1.38, 95% CI=1.2-1.6); polysubstance users had an even higher hazard (adjusted HR=1.95, 95% CI=1.5-2.4). In contrast, for participants with affective psychosis, cannabis predominant users (adjusted HR=1.10, 95% CI=0.8-1.4) and polysubstance users (adjusted HR=0.87, 95% CI=0.6-1.3) did not have a higher hazard of earlier age at onset compared with non-users.. Illicit substance use in the 12 months prior to psychosis onset has a differential effect on age at onset in schizophrenia spectrum and affective psychotic disorders. Our findings are compatible with the notion that illicit drugs bring forward age at onset in schizophrenia spectrum disorders but not affective psychotic disorders.

Topics: Adult; Age of Onset; Amphetamines; Australia; Cannabis; Cohort Studies; Female; Humans; Illicit Drugs; Male; Psychotic Disorders; Regression Analysis; Retrospective Studies; Schizophrenia; Substance-Related Disorders

Cannabis use disorder (CUD) occurs in up to 42% of patients with schizophrenia and substantially worsens disease progression. The basis of CUD in schizophrenia is unclear and available treatments are rarely successful at limiting cannabis use. We have proposed that a dysregulated brain reward circuit (BRC) may underpin cannabis use in these patients. In the present pilot study, we used whole-brain seed-to-voxel resting state functional connectivity (rs-fc) to examine the BRC of patients with schizophrenia and CUD, and to explore the effects of smoked cannabis and orally administered delta-9-tetrahydrocannabinol (THC) on the BRC. 12 patients with schizophrenia and CUD and 12 control subjects each completed two fMRI resting scans, with patients administered either a 3.6% THC cannabis cigarette (n=6) or a 15 mg THC capsule (n=6) prior to their second scan. Results revealed significantly reduced connectivity at baseline in patients relative to controls, with most pronounced hypoconnectivity found between the nucleus accumbens and prefrontal cortical BRC regions (i.e., anterior prefrontal cortex, orbitofrontal cortex, and anterior cingulate cortex). Both cannabis and THC administration increased connectivity between these regions, in direct correlation with increases in plasma THC levels. This study is the first to investigate interregional connectivity of the BRC and the effects of cannabis and THC on this circuit in patients with schizophrenia and CUD. The findings from this pilot study support the use of rs-fc as a means of measuring the integrity of the BRC and the effects of pharmacologic agents acting on this circuit in patients with schizophrenia and CUD.

Topics: Administration, Oral; Adult; Brain; Brain Mapping; Cannabinoid Receptor Agonists; Cannabis; Dronabinol; Female; Humans; Magnetic Resonance Imaging; Male; Marijuana Smoking; Neural Pathways; Pilot Projects; Rest; Reward; Schizophrenia; Substance-Related Disorders

The aim of the study was to determinate whether schizophrenia patients with a history of cannabis use have a different prognosis, with regards to readmission and hospital duration, compared with those without a history of cannabis use.. The present investigation was a cohort study of 50,087 Swedish men with data on cannabis use at the ages of 18-20 years. A total of 357 cases of schizophrenia were identified from in-patient care and followed up from 1973 to 2007.. Schizophrenia patients with a history of cannabis use had a higher median duration of first hospital episode (59 days v. 30 days). Patients with a history of cannabis use had a higher median rate of readmission (10 times v. four times). Also, total number of hospital days was higher in patients with a history of cannabis use compared with those without (547 days v. 184 days). Patients with a history of cannabis use had an increased odds of having more than 20 hospital readmissions compared with non-users [3.1, 95% confidence interval (CI) 1.3-7.3] as well as an increased odds of hospital admission lasting more than 2 years (2.4, 95% CI 1.1-7.4) after controlling for diagnosis of personality disorders, family socio-economic position, IQ score, civil status, place of residence, risky use of alcohol and use of other drugs. Patients with a history of cannabis use were less likely to have paranoid schizophrenia compared with never users (8% v. 17%) in the first admission.. Schizophrenia patients with a history of cannabis use had a significantly higher burden of lifetime in-patient care than non-cannabis users. Not only does cannabis increase the risk of schizophrenia, but also our findings indicate that the course and prognosis of schizophrenia may be more severe than schizophrenia cases in general.

Topics: Cannabis; Follow-Up Studies; Hospitalization; Humans; Length of Stay; Male; Middle Aged; Patient Readmission; Prognosis; Schizophrenia; Sweden

As more US states and other countries consider legalizing marijuana, clinicians need to know the possible effects of this drug. Research has shown a connection between marijuana use and an increased risk for schizophrenia in young people who are vulnerable to developing psychosis. An international panel of experts addresses topics such as risk factors for schizophrenia, the potency and effects of cannabis use on adolescents, the effects of concurrent drug use with cannabis on schizophrenia risk, and current attitudes toward marijuana.

Topics: Adolescent; Adult; Cannabis; Genetic Predisposition to Disease; Humans; Marijuana Abuse; Risk Factors; Schizophrenia

We present the case of a young man with a long-standing history of schizophrenia who presented with severe and life-threatening catatonia in the setting of synthetic cannabis use who was successfully treated with electroconvulsive therapy. To our knowledge, this is the first reported case of severe and persistent catatonia in the setting of synthetic cannabis use and the first documented successful treatment.

Topics: Adult; Cannabis; Catatonia; Designer Drugs; Electroconvulsive Therapy; Humans; Male; Marijuana Abuse; Schizophrenia; Treatment Outcome

Topics: Cannabis; Humans; Risk Factors; Schizophrenia

A disturbance in connectivity between different brain regions, rather than abnormalities within the separate regions themselves, could be responsible for the clinical symptoms and cognitive dysfunctions observed in schizophrenia. White matter, which comprises axons and their myelin sheaths, provides the physical foundation for functional connectivity in the brain. Myelin sheaths are located around the axons and provide insulation through the lipid membranes of oligodendrocytes. Empirical data suggests oligodendroglial dysfunction in schizophrenia, based on findings of abnormal myelin maintenance and repair in regions of deep white matter. The aim of this in vivo neuroimaging project is to assess the impact of early adolescent onset of regular cannabis use on brain white matter tissue integrity, and to differentiate this impact from the white matter abnormalities associated with schizophrenia. The ultimate goal is to determine the liability of early adolescent use of cannabis on brain white matter, in a vulnerable brain.. Young adults with schizophrenia at the early stage of the illness (less than 5 years since diagnosis) will be the focus of this project. Four magnetic resonance imaging measurements will be used to assess different cellular aspects of white matter: a) diffusion tensor imaging, b) localized proton magnetic resonance spectroscopy with a focus on the neurochemical N-acetylaspartate, c) the transverse relaxation time constants of regional tissue water, d) and of N-acetylaspartate. These four neuroimaging indices will be assessed within the same brain region of interest, that is, a large white matter fibre bundle located in the frontal region, the left superior longitudinal fasciculus.. We will expand our knowledge regarding current theoretical models of schizophrenia with a more comprehensive multimodal neuroimaging approach to studying the underlying cellular abnormalities of white matter, while taking into consideration the important confounding variable of early adolescent onset of regular cannabis use.

Topics: Adolescent; Adult; Cannabis; Diffusion Tensor Imaging; Female; Frontal Lobe; Humans; Male; Marijuana Smoking; Multimodal Imaging; Nerve Net; Neuroimaging; Research Design; Schizophrenia; White Matter; Young Adult

Cannabis use is widespread among patients with schizophrenia despite its negative impact on the course of the disease. Craving is a considerable predictor for relapse in people with substance use disorders. Our investigation aimed to gain insight into the intensity and dimensions of cravings in patients with schizophrenia and cannabis use disorders (CUDs), compared with otherwise healthy people with CUDs (control subjects).. We examined 51 patients with schizophrenia and CUDs and 51 control subjects by means of the Cannabis-Craving Screening questionnaire.. We found greater overall intensity of craving and greater relief craving in patients with schizophrenia and CUDs. Reward craving was greater in the CUDs group. Relief craving was associated with symptoms of schizophrenia in patients with schizophrenia and CUDs.. Our findings are in line with the view that aspects of self-medication or affect regulation may account (at least in part) for cannabis use in people with schizophrenia. A better understanding of the dimensions of craving may help to improve targeted therapeutic interventions that aim to reduce drug consumption in this difficult-to-treat patient group.

Topics: Adult; Cannabis; Case-Control Studies; Female; Humans; Male; Marijuana Abuse; Schizophrenia; Schizophrenic Psychology; Severity of Illness Index; Substance Withdrawal Syndrome; Young Adult

The medical properties of cannabis have been known for many centuries; its first documented use dates back to 2800 BC when it was described for its hallucinogenic and pain-relieving properties. In the first half of the twentieth century, a number of pharmaceutical companies marked cannabis for indications such as asthma and pain, but since then its use has sharply declined, mainly due to its unpredictable effects, but also for socio-political issues. Recently, great attention has been directed to the medical properties of phytocannabinoids present in the cannabis plant alongside the main constituent Δ⁹-Tetrahydrocannabinol (THC); these include cannabinoids such as cannabidiol (CBD), cannabigerol (CBG), and tetrahydrocannabivarin (THCV). Evidence suggests an association between cannabis and schizophrenia: schizophrenics show a higher use of marijuana as compared to the healthy population. Additionally, the use of marijuana can trigger psychotic episodes in schizophrenic patients, and this has been ascribed to THC. Given the need to reduce the side effects of marketed antipsychotics, and their weak efficacy on some schizophrenic symptoms, cannabinoids have been suggested as a possible alternative treatment for schizophrenia. CBD, a non-psychoactive constituent of the Cannabis sativa plant, has been receiving growing attention for its anti-psychotic-like properties. Evidence suggests that CBD can ameliorate positive and negative symptoms of schizophrenia. Behavioural and neurochemical models suggest that CBD has a pharmacological profile similar to that of atypical anti-psychotic drugs and a clinical trial reported that this cannabinoid is a well-tolerated alternative treatment for schizophrenia.

Topics: Animals; Antipsychotic Agents; Cannabidiol; Cannabis; Dronabinol; Humans; Marijuana Abuse; Psychoses, Substance-Induced; Schizophrenia; Schizophrenic Psychology

Schizophrenia is associated with various brain structural abnormalities, including reduced volume of the hippocampi, prefrontal lobes and thalami. Cannabis use increases the risk of schizophrenia but reports of brain structural abnormalities in the cannabis-using population have not been consistent. We used automated image analysis to compare brain structural changes over time in people at elevated risk of schizophrenia for familial reasons who did and did not use cannabis.. Magnetic resonance imaging (MRI) scans were obtained from subjects at high familial risk of schizophrenia at entry to the Edinburgh High Risk Study (EHRS) and approximately 2 years later. Differential grey matter (GM) loss in those exposed (n=23) and not exposed to cannabis (n=32) in the intervening period was compared using tensor-based morphometry (TBM).. Cannabis exposure was associated with significantly greater loss of right anterior hippocampal (pcorrected=0.029, t=3.88) and left superior frontal lobe GM (pcorrected=0.026, t=4.68). The former finding remained significant even after the exclusion of individuals who had used other drugs during the inter-scan interval.. Using an automated analysis of longitudinal data, we demonstrate an association between cannabis use and GM loss in currently well people at familial risk of developing schizophrenia. This observation may be important in understanding the link between cannabis exposure and the subsequent development of schizophrenia.

Topics: Adolescent; Adult; Cannabis; Cerebral Cortex; Female; Follow-Up Studies; Genetic Predisposition to Disease; Hippocampus; Humans; Magnetic Resonance Imaging; Male; Prefrontal Cortex; Schizophrenia; Scotland; Young Adult

Epidemiological data link adolescent cannabis use to psychosis and schizophrenia, but its contribution to schizophrenia neuropathology remains controversial. First-episode schizophrenia (FES) patients show regional cerebral grey- and white-matter changes as well as a distinct pattern of regional grey-matter loss in the vermis of the cerebellum. The cerebellum possesses a high density of cannabinoid type 1 receptors involved in the neuronal diversification of the developing brain. Cannabis abuse may interfere with this process during adolescent brain maturation leading to 'schizophrenia-like' cerebellar pathology. Magnetic resonance imaging and cortical pattern matching techniques were used to investigate cerebellar grey and white matter in FES patients with and without a history of cannabis use and non-psychiatric cannabis users. In the latter group we found lifetime dose-dependent regional reduction of grey matter in the right cerebellar lobules and a tendency for more profound grey-matter reduction in lobule III with younger age at onset of cannabis use. The overall regional grey-matter differences in cannabis users were within the normal variability of grey-matter distribution. By contrast, FES subjects had lower total cerebellar grey-matter:total cerebellar volume ratio and marked grey-matter loss in the vermis, pedunculi, flocculi and lobules compared to pair-wise matched healthy control subjects. This pattern and degree of grey-matter loss did not differ from age-matched FES subjects with comorbid cannabis use. Our findings indicate small dose-dependent effects of juvenile cannabis use on cerebellar neuropathology but no evidence of an additional effect of cannabis use on FES cerebellar grey-matter pathology.

Topics: Age Factors; Cannabis; Cerebellum; Comorbidity; Dose-Response Relationship, Drug; Female; Gray Matter; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Marijuana Abuse; Organ Size; Schizophrenia; White Matter; Young Adult

Substance abuse and psychotic disorders have a high rate of comorbidity. Both disorders are associated with changes in the dopaminergic transmission in the mesocorticolimbic pathways of the brain. Since antipsychotic medications interact with the dopamine receptors in these pathways, these medications could affect craving for substances. In the current study, the effect of clozapine (n = 27, mean dosage 350 mg), risperidone (n = 54, mean dosage 3.46 mg) and olanzapine (n = 60, mean dosage 13.78 mg) on subjective craving for cannabis was compared in 123 patients with cannabis dependence and psychotic disorder. Patients treated with risperidone reported significantly more craving compared with patients treated with clozapine (Z = -3.19, p = .001) or olanzapine (Z = -2.24, p = .025). No significant differences in craving between clozapine and olanzapine were found. These results are in concordance with findings in the literature on this subject and could be explained by differences in three dopamine mediated mechanisms of these compounds: 1) occupancy rate of dopamine D(2) receptors, 2) dissociation rate of dopamine D(2) receptors, 3) D(1)/D(2) occupancy ratio. Risperidone and clozapine show a maximal difference in D(2) receptor occupancy rate, dissociation rate and D(1)/D(2) ratio. Olanzapine is intermediate between risperidone and clozapine in these characteristics.

Topics: Adult; Antipsychotic Agents; Benzodiazepines; Cannabis; Clozapine; Cohort Studies; Dopamine; Female; Humans; Longitudinal Studies; Male; Marijuana Abuse; Olanzapine; Receptors, Dopamine D1; Receptors, Dopamine D2; Risperidone; Schizophrenia

There is now strong evidence that cannabis use increases the risk of psychoses including schizophrenia, but the relationship between cannabis and different psychotic disorders, as well as the mechanisms, are poorly known. We aimed to assess types of psychotic outcomes after use of cannabis in adolescence and variation in risk over time.. A cohort of 50 087 military conscripts with data on cannabis use in late adolescence was followed up during 35 years with regard to in-patient care for psychotic diagnoses.. Odds ratios for psychotic outcomes among frequent cannabis users compared with non-users were 3.7 [95% confidence interval (CI) 2.3-5.8] for schizophrenia, 2.2 (95% CI 1.0-4.7) for brief psychosis and 2.0 (95% CI 0.8-4.7) for other non-affective psychoses. Risk of schizophrenia declined over the decades in moderate users but much less so in frequent users. The presence of a brief psychosis did not increase risk of later schizophrenia more in cannabis users compared with non-users.. Our results confirm an increased risk of schizophrenia in a long-term perspective, although the risk declined over time in moderate users.

Topics: Adolescent; Adult; Cannabis; Epidemiologic Methods; Female; Humans; Marijuana Abuse; Middle Aged; Military Personnel; Psychotic Disorders; Schizophrenia; Sweden; Time Factors

Topics: Adolescent; Adult; Age of Onset; Alcohol Drinking; Cannabis; Causality; Child; Child, Preschool; Comorbidity; Dose-Response Relationship, Drug; Dronabinol; Female; Gene-Environment Interaction; Genetic Predisposition to Disease; Humans; Infant; Infant, Newborn; Marijuana Abuse; Marijuana Smoking; Pregnancy; Psychoses, Substance-Induced; Recurrence; Risk; Schizophrenia; Schizophrenic Psychology; Social Facilitation; Telecommunications; United States; Young Adult

Cannabis is one of the most commonly used illicit drugs, and despite the widely held belief that it is a safe drug, its long-term use has potentially harmful consequences. To date, the research on the impact of its use has largely been epidemiological in nature and has consistently found that cannabis use is associated with schizophrenia outcomes later in life, even after controlling for several confounding factors. While the majority of users can continue their use without adverse effects, it is clear from studies of psychosis that some individuals are more vulnerable to its effects than others. In addiction, evidence from both epidemiological and animal studies indicates that cannabis use during adolescence carries particular risk. Further studies are warranted given the increase in the concentration of the main active ingredient (Δ(9)-tetrahydrocannabinol) in street preparations of cannabis and a decreasing age of first-time exposure to cannabis.

Topics: Adolescent; Anxiety; Cannabis; Critical Period, Psychological; Humans; Marijuana Abuse; Mood Disorders; Risk Factors; Schizophrenia; Young Adult

No longitudinal study has yet examined the association between substance use and brain volume changes in a population at high risk of schizophrenia.. To examine the effects of cannabis on longitudinal thalamus and amygdala-hippocampal complex volumes within a population at high risk of schizophrenia.. Magnetic resonance imaging scans were obtained from individuals at high genetic risk of schizophrenia at the point of entry to the Edinburgh High-Risk Study (EHRS) and approximately 2 years later. Differential thalamic and amygdala-hippocampal complex volume change in high-risk individuals exposed (n = 25) and not exposed (n = 32) to cannabis in the intervening period was investigated using repeated-measures analysis of variance.. Cannabis exposure was associated with bilateral thalamic volume loss. This effect was significant on the left (F = 4.47, P = 0.04) and highly significant on the right (F= 7.66, P= 0.008). These results remained significant when individuals using other illicit drugs were removed from the analysis.. These are the first longitudinal data to demonstrate an association between thalamic volume loss and exposure to cannabis in currently unaffected people at familial high risk of developing schizophrenia. This observation may be important in understanding the link between cannabis exposure and the subsequent development of schizophrenia.

Topics: Adolescent; Adult; Amygdala; Analysis of Variance; Cannabis; Disease Progression; Female; Genetic Predisposition to Disease; Hippocampus; Humans; Longitudinal Studies; Magnetic Resonance Imaging; Male; Marijuana Abuse; Marijuana Smoking; Risk Factors; Schizophrenia; Thalamus; Time Factors; Young Adult

Increasing interest in the prodromal stage of schizophrenia over the past decade led us to perform our study to monitor people at high risk for developing a psychosis. We hypothesized that cannabis use or a cannabis use disorder at a younger age relates to high-risk symptoms at a younger age.. People referred to the Academic Medical Centre in Amsterdam, the Netherlands, with an ultra-high risk (UHR) for psychosis were interviewed with the Composite International Diagnostic Interview to assess their cannabis consumption. The Interview for the Retrospective Assessment of the Onset of Schizophrenia was used to collect data about age of onset of high-risk or prodromal symptoms. Nine high-risk symptoms were selected and clustered because of their known relation with cannabis use.. Among the 68 included participants, 35 had used cannabis (51.5%), of whom 15 had used recently. Twenty-two participants had been cannabis abusers or cannabis-dependent (32.4%) in the past. Younger age at onset of cannabis use was related to younger age of onset of the cluster of symptoms (rho = 0.48, P = 0.003) and also to 6 symptoms individually (rho = 0.47 to 0.90, P < 0.001 to 0.04). Younger age at onset of a cannabis use disorder was related to younger age of onset of the cluster of symptoms (rho = 0.67, P = 0.001) and also to 6 symptoms individually (rho = 0.50 to 0.93, P = 0.007 to 0.03).. Cannabis use or a cannabis use disorder at a younger age in a group with an UHR for transition to psychosis is related to onset of high-risk symptoms for psychosis at a younger age.

Topics: Adolescent; Adult; Age Factors; Age of Onset; Cannabis; Child; Humans; Marijuana Abuse; Netherlands; Retrospective Studies; Risk Factors; Schizophrenia; Young Adult

Cerebral grey matter volume reductions are progressive in schizophrenia, with larger grey matter volume decreases associated with cannabis use. It is unknown whether this grey matter loss is globally distributed over the entire brain or more pronounced in specific cortical brain regions. Fifty-one patients with recent-onset schizophrenia and 31 matched healthy subjects were included. For all subjects, magnetic resonance imaging scans were obtained at inclusion and at 5-year follow-up. Nineteen patients (ab-)used cannabis but no other illicit drugs; 32 patients and the healthy comparison subjects did not use any drugs during the 5-year follow-up. At follow-up, clinical outcome was measured. To evaluate the local differences in cortical thickness change over five years between the two groups regression analysis was carried out over the cortical surface. At inclusion cortical thickness did not differ between patients and controls and between cannabis-using and non-using patients. Over the follow-up period we found excessive thinning of the right supplementary motor cortex, inferior frontal cortex, superior temporal gyrus, angular gyrus, occipital and parietal lobe in patients relative to controls after controlling for cannabis use. Patients who used cannabis showed additional thinning in the left dorsolateral prefrontal cortex (DLPFC), left anterior cingulate cortex (ACC) and left occipital lobe as compared to those patients that did not use cannabis during the scan interval. First-episode schizophrenia patients who use cannabis show a more pronounced cortical thinning than non-using patients in areas known for their high density of CB1 receptors, such as the ACC and the DLPFC.

Topics: Adolescent; Adult; Cannabis; Cerebral Cortex; Disease Progression; Female; Follow-Up Studies; Humans; Male; Marijuana Abuse; Organ Size; Receptor, Cannabinoid, CB1; Schizophrenia; Time Factors; Young Adult

Cognitive deficits are commonly found both in patients with schizophrenia (SCH) and in people with cannabis use disorders (CUD). Surprisingly, some small recent studies reported better cognitive performance in SCH patients with comorbid cannabis use disorders (SCH + CUD) compared to other SCH patients.. The aim of the present study was to investigate the residual impact of CUD and specific patterns of consumption on cognition in a larger sample of SCH + CUD patients.. We administered a cognitive test battery to 34 SCH and 35 currently abstinent SCH + CUD patients. We explored the association between patterns of cannabis consumption and cognitive performance. Potential confounds with influence on cognitive ability were assessed and controlled for.. SCH + CUD patients had poorer academic achievements and lower vocabulary scores, but they performed better in tests of verbal and working memory, visuomotor speed and executive function (p < .05). More frequent cannabis use was associated with better performance in attention and working memory tasks.. Although our findings might be interpreted as beneficial effect of cannabis use on cognition in patients with schizophrenia, we favorise an alternative interpretation: in our view, the better cognitive functioning of SCH + CUD patients may rather reflect a relatively lower vulnerability to psychosis compared to the SCH group. Lower vulnerability may correspond to a higher level of functioning such as cognitive ability. This conclusion is consistent with the view of cannabis playing a critical role in the manifestation of psychosis in at least some of the SCH + CUD patients.

Topics: Adult; Analysis of Variance; Cannabis; Chi-Square Distribution; Cognition Disorders; Female; Humans; Male; Marijuana Abuse; Neuropsychological Tests; Schizophrenia; Statistics, Nonparametric

Topics: Brain; Cannabis; Humans; Psychoses, Substance-Induced; Schizophrenia

Topics: Cannabis; Confounding Factors, Epidemiologic; Cost of Illness; Humans; Observation; Psychotic Disorders; Risk Assessment; Risk Factors; Schizophrenia

Topics: Cannabis; Drug and Narcotic Control; Humans; Marijuana Abuse; Marijuana Smoking; Schizophrenia; United Kingdom

Controversy exists regarding whether young people at risk for schizophrenia are at increased risk of adverse mental effects of cannabis use.. We examined cannabis use and mental health functioning in three groups of young people aged 14-21; 36 non-psychotic siblings of adolescents with schizophrenia (genetic high risk group), 25 adolescents with attention deficit hyperactivity disorder (ADHD) and 72 healthy controls. The groups were sub-divided into 'users' and 'non-users' of cannabis based on how often they had used cannabis previously. Mental health functioning was quantified by creating a composite index derived from scores on the Schizotypal Personality Questionnaire (SPQ), Strengths and Difficulties Questionnaire (SDQ) and Global Assessment of Function (GAF).. A significant positive association between cannabis use and mental health disturbance was confined to young people at genetic high risk for schizophrenia. To determine whether the relationship was specific to particular dimensions of mental health function, a second composite index was created based on scores from the SPQ Disorganisation and SDQ hyperactivity-inattention sub-scales. Again, there was a significant positive association between cannabis use and factor scores which was specific to the genetic high risk group. There was a trend for this association to be negative in the ADHD group (p=0.07).. The findings support the view that young people at genetic high risk for schizophrenia are particularly vulnerable to mental health problems associated with cannabis use. Further research is needed to investigate the basis of relationships between cannabis and mental health in genetically vulnerable individuals.

Topics: Adolescent; Adult; Attention Deficit Disorder with Hyperactivity; Cannabis; Cognition Disorders; Control Groups; Cross-Sectional Studies; Female; Genetic Predisposition to Disease; Humans; Male; Marijuana Abuse; Neuropsychological Tests; Prevalence; Psychiatric Status Rating Scales; Psychology, Adolescent; Risk Factors; Schizophrenia; Schizophrenic Psychology; Severity of Illness Index; Surveys and Questionnaires

Patterns of successive saccades and fixations (scan paths) that are made while viewing images are often spatially restricted in schizophrenia, but the relation with cannabis-induced psychosis has not been examined. We used higher-order statistical methods to examine spatiotemporal characteristics of scan paths to determine whether viewing behaviour was distinguishable on a continuum.. Patients with early acute first-episode paranoid schizophrenia (SCH; n = 11), cannabis-induced psychosis (CIP; n = 6) and unaffected control subjects (n = 22) undertook a task requiring free viewing of facial, fractal and landscape images for 5 seconds while their eye movements were recorded. Frequencies and distributions of saccades and fixations were calculated in relation to image regions examined during each trial.. Findings were independent of image category, indicating generalized scanning deficits. Compared with control subjects, patients with SCH and CIP made fewer saccades and fewer fixations of longer duration. In turn, the spatial distribution of fixations in CIP patients was more clustered than in SCH and control subjects. The diversity of features fixated in subjects with CIP was also lower than in SCH patients and control subjects.. A continuous approach to characterizing scan path changes in different phenotypes suggests that CIP shares some of the abnormalities of SCH but can be distinguished with measures that are sensitive to cognitive strategies active or inhibited during visual exploration.

Topics: Adult; Cannabis; Eye Movements; Female; Fixation, Ocular; Humans; Male; Photic Stimulation; Psychiatric Status Rating Scales; Psychoses, Substance-Induced; Schizophrenia; Schizophrenic Psychology

To describe and discuss the implications for treatment of 3 cases of dually diagnosed patients with a primary psychotic disorder who have developed persisting, cannabis-oriented delusional systems.. Psychiatric assessment and daily observation on an acute inpatient psychiatric unit.. Abstinence appears to be particularly difficult to attain for a patient with psychosis who hold delusional beliefs that cannabis is a conduit for supernormal experiences with positive affective content, grandiose themes and a sense of enhanced self-efficacy.. This phenomenon poses special challenges in the treatment of dual diagnosis patients. Modifications to existing CBT protocols for the treatment of substance abuse in psychosis might be useful in such patients.

Topics: Adult; Bipolar Disorder; Cannabis; Cognitive Behavioral Therapy; Comorbidity; Delusions; Diagnosis, Dual (Psychiatry); Hospitalization; Humans; Male; Marijuana Abuse; Models, Psychological; Psychiatric Department, Hospital; Psychoses, Substance-Induced; Psychotic Disorders; Schizophrenia; Schizophrenic Psychology; Treatment Outcome

Available information regarding the clinical features of cannabis-induced psychoses among schizophrenia patients is rather odd and even discrepant. For thorough investigation psychopathology due to marijuana intoxication, we examine two groups of schizophrenia patients. I group--14 patients, who had long history of cannabis use before developing schizophrenia, and II group--schizophrenic patients, who already had schizophrenia and later became marijuana users. Clinical study allowed us to determine the general psychopathological symptoms due to acute intoxication on the one hand, reflecting duration and severity of intoxication, and let us to verify specific mental problems connected to the dynamics of schizophrenia, on the other hand. Peculiar properties of the data of the experimental-psychological tests TAT (Thematic Apperception Test) reflect personality changes generated by schizophrenia progression included the psychopathological phenomenon related to cannabis intoxication. Psychopharmacological treatment brought positive changes in structure and thematic features of the data. The patients used more words. The content and the volume of the stories increased. Trends to improvement were more common for recurrent rather than continuous duration of schizophrenia.

Topics: Adolescent; Adult; Cannabis; Humans; Male; Marijuana Abuse; Psychoses, Substance-Induced; Schizophrenia

Topics: Adult; Antipsychotic Agents; Basal Ganglia Diseases; Cannabis; Humans; Male; Schizophrenia

Cannabis is currently the most commonly used illegal psychoactive substance amongst young people aged between 15 and 24, and it seems that 5% of this age group is addicted to it. Many research teams focused particularly on the cognitive disorders caused by cannabis use. Amongst the cognitive functions considered, memory-related, attention-related, psychomotor and motivation-related functions were proved deteriorated by acute and chronic cannabis use; a very important point, especially among teenagers, as possible alteration at the social and academic level could be the outcome. However studies on long-term and persistent cognitive effects haven't provided convergent conclusions. Methodological differences could partly affect these observations. Therefore it seems necessary to develop studies with larger samples.

Topics: Adolescent; Adult; Age Factors; Cannabis; Cognition Disorders; Humans; Marijuana Abuse; Research; Risk; Risk Factors; Schizophrenia; Time Factors

Cannabis disorders, according to the DSM-IV and the ICD-10 criteria, include cannabis intoxication, cannabis abuse, cannabis dependence, and cannabis-related disorders (anxiety disorders, psychotic disorders, cannabis intoxication delirium). Although cannabis withdrawal syndrome has clinical importance, it is not included in these classifications. The amotivational syndrome remains controversial. The psychiatric disorders related to cannabis use are anxiety disorders, depressive disorders and psychotic disorders. Cannabis use could be closely linked with the neurobiology of schizophrenia. As the other psychoactive substances, cannabis use worsens the psychiatric outcomes and is associated with poorer treatment compliance.

Topics: Adolescent; Alcohol Drinking; Anxiety Disorders; Cannabis; Comorbidity; Depressive Disorder; Humans; Male; Marijuana Abuse; Mental Disorders; Patient Compliance; Psychotic Disorders; Schizophrenia; Time Factors

Few studies have examined samples of people with cannabis-induced psychotic symptoms.. To establish whether cannabis-induced psychotic disorders are followed by development of persistent psychotic conditions, and the timing of their onset.. Data on patients treated for cannabis-induced psychotic symptoms between 1994 and 1999 were extracted from the Danish Psychiatric Central Register. Those previously treated for any psychotic symptoms were excluded. The remaining 535 patients were followed for at least 3 years. In a separate analysis, the sample was compared with people referred for schizophrenia-spectrum disorders for the first time, but who had no history of cannabis-induced psychosis.. Schizophrenia-spectrum disorders were diagnosed in 44.5% of the sample. New psychotic episodes of any type were diagnosed in 77.2%. Male gender and young age were associated with increased risk. Development of schizophrenia-spectrum disorders was often delayed, and 47.1% of patients received a diagnosis more than a year after seeking treatment for a cannabis-induced psychosis. The patients developed schizophrenia at an earlier age than people in the comparison group (males, 24.6 v. 30.7 years, females, 28.9 v. 33.1 years).. Cannabis-induced psychotic disorders are of great clinical and prognostic importance.

Topics: Adult; Age Factors; Age of Onset; Cannabis; Denmark; Female; Follow-Up Studies; Humans; Incidence; Male; Marijuana Abuse; Psychotic Disorders; Recurrence; Risk Factors; Schizophrenia; Sex Factors

Topics: Adolescent; Adult; Age of Onset; Analysis of Variance; Brain; Cannabis; Female; Humans; Magnetic Resonance Imaging; Male; Marijuana Abuse; Prevalence; Psychiatric Status Rating Scales; Psychoses, Substance-Induced; Psychotic Disorders; Schizophrenia; Schizophrenic Psychology; Severity of Illness Index

Topics: Cannabis; Humans; Psychotic Disorders; Schizophrenia

Topics: Adult; Cannabis; Humans; Psychotic Disorders; Risk Factors; Schizophrenia

Neurotrophins such as nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) are critically implicated in development and maintenance of function of neurons. Neurodevelopment is reported to be impaired in schizophrenia and vulnerable schizophrenic brains may be more sensitive to toxic influences. Thus, cannabis as a neurotoxin, may be more harmful to schizophrenic brains than to non-schizophrenic brains when used chronically. And neurotoxic events may promote disease-onset and lead to exaggerated release of neurotrophins. We investigated 157 drug-naive first-episode schizophrenic patients and found significantly elevated BDNF serum concentrations (by up to 34%) in patients with chronic cannabis abuse (n = 35, p < 0.001) or multiple substance abuse (n = 20, p < 0.001) prior to disease onset. Drug-naive schizophrenic patients without cannabis consumption showed similar results to normal controls and cannabis controls without schizophrenia. Thus, raised BDNF serum levels are not related to schizophrenia and/or substance abuse itself but may reflect a cannabis-related idiosyncratic damage of the schizophrenic brain. In line with this hypothesis, disease onset was 5.2 years earlier in the cannabis-consuming group (p = 0.0111).

Topics: Adult; Amphetamine-Related Disorders; Brain-Derived Neurotrophic Factor; Cannabis; Cocaine-Related Disorders; Female; Humans; Male; Marijuana Abuse; Schizophrenia

Alcohol and cannabis use disorders worsen the course of schizophrenia. While the typical antipsychotics are of limited value in controlling substance use in schizophrenic patients, previous studies suggest that the novel antipsychotic clozapine (CLOZ) may decrease their substance use. We describe a retrospective study of the effects of the novel antipsychotics risperidone (RISP) and clozapine on alcohol and cannabis use in patients with schizophrenia or schizoaffective disorder and comorbid alcohol and/or cannabis use disorder.. This study involved retrospective assessment of abstinence (cessation of alcohol and cannabis use) in 41 patients treated with either risperidone (n=8) or clozapine (n=33) for at least 1 year. In 32 of these 41 patients, information was available on whether abstinence occurred during the 1-year period.. Abstinence rates were significantly higher in patients treated with clozapine than in those treated with risperidone (54% vs. 13%, p=0.05). The nine patients treated for at least 1 year, but excluded from the analysis because time of cessation of use was not known, had all stopped alcohol/cannabis use during clozapine treatment.. While the limitations of this retrospective study must be recognized, the data suggest that comorbid patients treated with clozapine are more likely to abstain from alcohol and cannabis use than are those treated with risperidone. Further prospective studies will be required to confirm these intriguing results.

Topics: Adult; Aged; Alcohols; Antipsychotic Agents; Cannabis; Clozapine; Female; Humans; Male; Middle Aged; Psychiatric Status Rating Scales; Retrospective Studies; Risperidone; Schizophrenia; Substance-Related Disorders; Treatment Outcome

This study investigated if changes in pre-synaptic markers on dopaminergic neurons (dopamine transporter [DAT], tyrosine hydroxylase [TH]) were present in the caudate from subjects with schizophrenia who had Delta(9)(-)tetrahydrocannabinol (THC) in their blood at autopsy. These changes were posited because animal studies show that treatment with THC decreases dopamine uptake and TH in the striatum.. Studies utilized caudate, obtained postmortem, from 14 schizophrenic and 14 control subjects. [(3)H]mazindol binding to caudate, measured using autoradiography, was taken as a measure of DAT; TH levels were estimated using an antihuman TH antibody and Western blotting.. There was decreased [(3)H]mazindol binding to DAT in the caudate from the schizophrenic subjects with no detectable blood THC levels (THC(-)) compared with THC(-) control subjects (mean +/- SEM: 240 +/- 19 vs. 296 +/- 14 fmol/mg estimated tissue equivalents, p =.01). There were no significant differences between levels of DAT in the caudate from schizophrenic and control subjects that had THC in their blood. Tyrosine hydroxylase was not different in any diagnostic cohort.. Our data suggests that DAT is decreased in the caudate from THC(-) subjects with schizophrenia, a change that may be reversed by ingesting THC from cannabis.

Topics: Adult; Analysis of Variance; Autopsy; Biomarkers; Cannabinoids; Cannabis; Caudate Nucleus; Central Nervous System; Dopamine; Dopamine Plasma Membrane Transport Proteins; Dronabinol; Female; Humans; Male; Membrane Glycoproteins; Membrane Transport Proteins; Middle Aged; Nerve Tissue Proteins; Schizophrenia; Tyrosine 3-Monooxygenase

To study the role of cannabis use in the onset of symptoms and disorders in the schizophrenia spectrum.. Literature study.. Hypothetical explanations of the relationship between cannabis use and subsequent schizophrenia were assessed on the basis of the results of five large longitudinal studies.. Because cannabis use preceded the development of schizophrenia and as a result of statistical control for possible confounders, the following explanations could be rejected: 'cannabis is used as self-medication for schizophrenia', 'schizophrenia is not caused by cannabis but by other drugs that are used concurrently', and 'cannabis use and schizophrenia are both caused by other factors'. Two explanations then remained: 'cannabis use per se contributes in a unique manner to the risk' and 'cannabis use, in interaction with other risk factors, leads to an increase in the risk'.. There are strong indications that cannabis use increases the risk of the subsequent development of symptoms and disorders in the schizophrenia spectrum.

Topics: Cannabis; Humans; Longitudinal Studies; Marijuana Smoking; Psychoses, Substance-Induced; Risk Factors; Schizophrenia

Long-term cannabis abuse may increase the risk of schizophrenia. Nerve growth factor (NGF) is a pleiotropic neurotrophic protein that is implicated in development, protection and regeneration of NFG-sensitive neurones. We tested the hypothesis that damage to neuronal cells in schizophrenia is precipitated by the consumption of cannabis and other neurotoxic substances, resulting in raised NGF serum concentrations and a younger age for disease onset. The NGF serum levels of 109 consecutive drug-naive schizophrenic patients were measured and compared with those of healthy controls. The results were correlated with the long-term intake of cannabis and other illegal drugs. Mean (+/- SD) NGF serum levels of 61 control persons (33.1 +/- 31.0 pg/ml) and 76 schizophrenics who did not consume illegal drugs (26.3 +/- 19.5 pg/ml) did not differ significantly. Schizophrenic patients with regular cannabis intake (> 0.5 g on average per day for at least 2 years) had significantly raised NGF serum levels of 412.9 +/- 288.4 pg/ml (n = 21) compared to controls and schizophrenic patients not consuming cannabis (p < 0.001). In schizophrenic patients who abused not only cannabis, but also additional substances, NGF concentrations were as high as 2336.2 +/- 1711.4 pg/ml (n = 12). On average, heavy cannabis consumers suffered their first episode of schizophrenia 3.5 years (n = 21) earlier than schizophrenic patients who abstained from cannabis. These results indicate that cannabis is a possible risk factor for the development of schizophrenia. This might be reflected in the raised NGF-serum concentrations when both schizophrenia and long-term cannabis abuse prevail.

Topics: Adolescent; Adult; Cannabis; Drug Interactions; Female; Humans; Illicit Drugs; Male; Marijuana Abuse; Middle Aged; Nerve Growth Factor; Risk Factors; Schizophrenia; Schizophrenic Psychology; Substance-Related Disorders

Topics: Borrelia burgdorferi; Cannabis; Chromosomes, Human, Pair 6; Gene Transfer, Horizontal; Humans; Mutation; Psychoses, Substance-Induced; Receptors, Cannabinoid; Receptors, Drug; Schizophrenia

The existence of cannabis-induced psychosis (CP) remains controversial, partly because of methodological problems. We hypothesize that acute schizophrenia (AS) and CP can have distinct demographic, premorbid and clinical features.. We compared 26 patients with CP to 35 with AS, after their cannabis-consumption status was confirmed by repeated urine screens. Patients with CP were assessed after at least 1 week but not more than 1 month of abstinence. Symptoms were evaluated with the Present State Examination (PSE).. In group CP, male gender, expansive mood and ideation, derealization/depersonalization, visual hallucinations, and disturbances of sensorium were more frequent than in group AS. Premorbid schizoid personality traits were more frequently associated to AS and antisocial personality traits to CP.. The continuous heavy use of cannabis can induce a psychotic disorder distinct from AS. These two clinical entities share some features but they differ in others.

Topics: Acute Disease; Adult; Cannabis; Cross-Sectional Studies; Female; Humans; Male; Marijuana Abuse; Personality; Psychiatric Status Rating Scales; Psychoses, Substance-Induced; Schizophrenia

A number of studies suggested that cannabis use can cause or exacerbate psychoses and may increase the risk of developing schizophrenia. These findings suggest that changes in the cannabinoid system of the brain may be involved in the pathology of schizophrenia. To determine whether changes in the cannabinoid system were present in the brains of subjects with schizophrenia, we used in situ radioligand binding and autoradiography to measure the binding of [3H]CP-55940 to the cannabinoid-1 receptor in the dorsolateral prefrontal cortex (Brodmann's area 9), caudate-putamen and areas of the temporal lobe from schizophrenic and control subjects, some of whom had ingested cannabis close to death. There was an increase in the density of [3H]CP-55940 binding to cannabinoid-1 receptors in the dorsolateral prefrontal cortex from subjects with schizophrenia (mean+/-S.E.M.: 142+/-9.9 vs 119+/-6.6fmol/mg estimated tissue equivalents; P<0.05) that was independent of recent cannabis ingestion. There was an increase in the density of cannabinoid-1 receptors in the caudate-putamen from subjects who had recently ingested cannabis (151+/-9.0 vs 123+/-7.2fmol/mg estimated tissue equivalents; P<0.05) that was independent of diagnoses. These data indicate that there are changes in cannabinoid-1 receptors in the dorsolateral prefrontal cortex that may prove to be associated with the pathology of schizophrenia. By contrast, changes in the density of cannabinoid-1 receptors may occur in the caudate-putamen in response to cannabis ingestion.

Topics: Brain; Cannabinoids; Cannabis; Cyclohexanols; Dronabinol; Humans; In Vitro Techniques; Radioligand Assay; Receptors, Cannabinoid; Receptors, Drug; Schizophrenia; Substance-Related Disorders

Topics: Automobile Driving; Cannabis; Cognition Disorders; Humans; Marijuana Abuse; Prevalence; Psychomotor Performance; Public Health; Respiration Disorders; Schizophrenia

Topics: Adolescent; Cannabis; Female; Humans; Male; Marijuana Smoking; Psychoses, Substance-Induced; Schizophrenia

The efficacy of an adjuvant application of carbamazepine in cannabis-related schizophrenia-like psychosis not responsive to neuroleptic treatment is reported for the first time. In two patients, psychotic states occurred after continuous cannabis consumption over a period of 8 and 18 months, respectively, which were mainly characterized by severe thought disorders, disturbances of perception, delusions and weak affect. Both patients were admitted to hospital with no previous clinical history of psychotic episodes. After nonresponsive treatment with neuroleptics over several weeks, they both rapidly responded to additional medication with carbamazepine within a week after onset with a marked reduction in clinical signs and symptoms.

Topics: Adult; Cannabis; Carbamazepine; Humans; Male; Psychotic Disorders; Schizophrenia; Time Factors

Establishment of residual cognitive and psychotic effects (effects present at the time that all active cannabinoids are eliminated from the body) putatively produced by prolonged heavy cannabis use is difficult, because of many confounding variables like slow elimination of active cannabinoids, lack of supervision during abstinence, poor use of well-matched control groups and the presence of withdrawal symptoms. Residual cognitive effects were observed in some but not in all tests after prolonged heavy cannabis use. The effects were mostly mild. The relationship of cannabis use, psychotic effects and schizophrenia was unclear; the cannabis conceivably gave relief, but it also appeared that cannabis caused schizophrenia in young people and (or) enhanced the symptoms, especially in young people poorly able to cope with stress or in whom the antipsychotic therapy was unsuccessful.

Topics: Adolescent; Cannabinoids; Cannabis; Chronic Disease; Cognition; Cognition Disorders; Confounding Factors, Epidemiologic; Diagnosis, Differential; Drug Residues; Female; Humans; Male; Psychoses, Substance-Induced; Schizophrenia; Substance Withdrawal Syndrome; Substance-Related Disorders

Cognitive impairments during psychotic episodes are assumed to be caused not only by one single putative classical neurotransmitter dysfunction but also to be due to an impaired equilibrium of the interaction between different neurobiological generators of cognitive processes. Here, the perceptual abnormalities induced by psychotogenic agents play a major role as tools for understanding model psychoses. The recently discovered cannabinoid receptor system with its endogenous ligand anandamide can be regarded as an extremely relevant regulation system, a dysfunctionality of which may explain at least one subtype of endogenous psychoses. The present paper discusses the possible associations between the endogenous anandamide/cannabinoid system and schizophrenic psychoses. Neuropsychological experiments with the 3-D inversion paradigm were performed in healthy volunteers intoxicated with delta9-Tetrahydrocannabinol (delta9-THC). The 3-D inversion paradigm represents a visual illusion of binocular depth perception. Such an inversion occurs in many cases, especially when objects with a higher degree of familiarity (e.g. photographs of faces) are displayed. It is assumed that cognitive factors override the binocular disparity cues of stereopsis. We tested the hypothesis that, during psychotic and related prepsychotic states, the human CNS is unable to correct implausible perceptual hypotheses. Our study provides evidence of strong similarities between data acquired from patients, suffering from productive schizophrenic psychoses and delta9-THC-intoxicated healthy volunteers, as concerns disturbances in the internal regulation of perceptual processes.

Topics: Arachidonic Acids; Cannabinoids; Cannabis; Endocannabinoids; Humans; Polyunsaturated Alkamides; Schizophrenia; Schizophrenic Psychology; Time Factors; Visual Perception

Topics: Animals; Cannabis; Dronabinol; Female; Fetal Growth Retardation; Humans; Nausea; Pain; Pregnancy; Schizophrenia; Vomiting

First-degree relatives (FDRs) of 162 schizophrenic and 106 control probands were investigated [corrected]. Psychiatric morbidity was present in 34.8% of FDRs of schizophrenic probands and in 9.2% of FDRs of controls. There was significantly more psychiatric illness in the siblings and parents than in the offspring of both schizophrenic and control subjects. The morbidity risks for schizoid-schizotypal personality disorders, cannabis-use disorder and paranoid personality disorder were significantly higher in the FDRs of schizophrenic patients than in those of controls, suggesting a biological relationship.

Topics: Adolescent; Adult; Cannabis; Female; Heroin; Humans; Male; Middle Aged; Prevalence; Psychiatric Status Rating Scales; Schizophrenia; Schizophrenic Psychology; Sex Factors; Substance-Related Disorders

By means of the Stockholm County inpatient care register we identified all cases treated with a diagnosis of cannabis dependence and psychosis, not necessarily at the same occasion, during 1971-1983. By scrutinizing medical records, we evaluated the diagnosis according to DSM-III-R and we assessed the history of substance abuse as well as the psychiatric history and clinical course. We identified 229 cases during the follow-up; 112 of these cases (49%) fulfilled the DSM-III-R criteria for schizophrenia. The majority of the schizophrenics had prominent positive symptoms and a sudden onset of disease, and 69% of the cases had a record of heavy cannabis abuse at least 1 year before onset of psychotic symptoms. The high number of verified DSM-III-R cases of schizophrenia in this cohort and the temporal relation between cannabis abuse and schizophrenia further support the hypothesis that cannabis abuse may be a risk factor for schizophrenia. We confirmed previous observations that cannabis-associated schizophrenia often has a sudden onset and prominent positive symptoms.

Topics: Cannabis; Female; Hospitalization; Hospitals, Psychiatric; Humans; Length of Stay; Longitudinal Studies; Male; Psychiatric Status Rating Scales; Psychoses, Substance-Induced; Schizophrenia; Substance-Related Disorders; Sweden

Topics: Cannabis; Humans; Schizophrenia

Topics: Brain; Cannabinoids; Cannabis; Dronabinol; Humans; Schizophrenia

Topics: Adult; Cannabinoids; Cannabis; Female; Hallucinations; Humans; Male; Marijuana Abuse; Middle Aged; Schizophrenia; Schizophrenic Psychology

From 237 patients examined for drug-induced psychoses, 50 cannabis psychoses were examined according to the criterion "main cause of addiction" and 107 were examined according to the criterion "consumption during the last three months before hospitalization". The cannabis psychoses were compared to the other drug-induced psychoses as well as to a control group consisting of 219 schizophrenic patients. General agreement was found with the other drug-induced psychoses as well as with the group of schizophrenic patients. The variation from the symptomatology of the schizophrenics is generally common to both the cannabis psychoses and the other drug-induced psychoses. Judging by the results of our investigations, it must be concluded that there is no disease "cannabis psychosis" in its own right, just as the disease "drug-induced psychosis" also does not exist in its own right. While there is a certain slight drug-specific psychopathological undertone, it does not entitle us to speak of a syndromatic or indeed a nosological entity. The psychopathological cross section does not permit a differentiation in the individual psychoses groups mentioned, although this has often been attempted in the literature. That there are no relevant psychopathological differences between cannabis psychoses and endogenous schizophrenia could, for one, be based on the fact that we are observing the final stage of one and the same underlying pathological process. In this case both syndromes would in practice be endogenous psychoses, with the cause not being known in one case. The psychopathologic similarity of these two psychoses forms could, however, also be based on the assumption that cannabis psychoses are triggered schizophrenias, so that we could in both cases be dealing with one and the same disease. We see the solution to the problem of diagnosing symptomatic psychoses, and in particular cannabis psychoses, in making a diagnosis that takes the etiology into consideration in addition to the syndrome diagnosis.

Topics: Adolescent; Adult; Cannabis; Diagnosis, Differential; Female; Humans; Male; Psychoses, Substance-Induced; Schizophrenia

The use of marijuana as the independent variable produced a serious exacerbation of a psychotic process in four schizophrenic patients whose illness was otherwise well controlled with antipsychotic medication. Each patient served as his own control--the sole substance abused was marijuana and antipsychotic medication intake remained constant. Each time marijuana use at moderate levels began, there was exacerbation and deterioration. The author suggests that marijuana use is a special hazard to schizophrenic patients and that physicians should alert such high-risk patients to the possible untoward interaction between their illness and marijuana.

Topics: Acute Disease; Adult; Antipsychotic Agents; Cannabis; Humans; Male; Psychoses, Substance-Induced; Schizophrenia; Schizophrenic Psychology; Substance-Related Disorders

Among the psychotic symptoms in juvenile drug-consumers one can find autonomous, i.e. drug-independent developments, whose connection with the drug-abuse is to be assessed in differing ways. A beginning psychosis can be modified in its actual symptoms by drug-consumption. On the other hand one must consider the manifestation of a latent psychosis or purely symptomatic psychosis, which, in its symptoms, can hardly be distinguished from schizophrenia. Finally drug-induced personality-changes can develop together with secondary psychotic symptoms. Psychotic symptoms are determined and influenced in a varying degree by drugs. Both after short drug-consumption and after a longer drug-anamnesis with polytoxicomanic symptoms psychotic syndromes can be discovered. Even the initial psychotic symptoms can hint at an adverse development and a bad prognosis. Sometimes the drug-experiences conceal the autonomous development of the psychosis, which, as a rule, shows predominantly schizophrenic symptoms. In addition to a quick change of the actual symptoms, acute states of confusion and depressive-suicidal syndromes, flash-back and horror-trip phenomena, closely connected with the psychotic experience, and a schizophrenic colouring of affective psychoses can be found as frequently drug-induced modifications of the psychotic symptoms. Furthermore one finds an increase of symptoms and of the psychotic episodes in the case of psychoses of the schizophrenic variety which have already begun. Grave personality changes with psychotic symptoms after chronic drug-abuse can cause differential-diagnostic difficulties.

Topics: Adolescent; Adult; Bipolar Disorder; Cannabis; Female; Humans; Lysergic Acid Diethylamide; Male; Mescaline; Opium; Personality Disorders; Psychoses, Substance-Induced; Psychotic Disorders; Schizophrenia; Schizophrenic Psychology; Substance-Related Disorders; Suicide, Attempted; Syndrome; Time Factors

In a series of 103 psychotic patients with evidence of drug abuse, the following facts came to light. 1. A definitive diagnosis was made in 94%. In 6% of these cases the diagnosis remained unclear even after having been admitted for a second time. 2. Seventy-four percent (72 of 97) of the patients, who abused various drugs, usually in combination had organic psychoses, and 26% (25 of 97) were diagnosed as schizophrenics. 3. Of 36 patients, who suffered psychotic episodes due to the abuse of cannabis, or LSD, or heroin, 21 (= 58%) were schizophrenics. 4. In those cases showing organic psychoses, thought insertion, thought withdrawal, and thought broadcasting were not found. However all other first- (and second-) rank symptoms (Kurt Schneider) of schizophrenia were found. Perhaps this might be of help as a differential criterion. 5. The fact of drug abuse at the outset of a schizophrenia is dependent on the schizophrenic symptomatology. The use of and attitude to the drug as well as the experiencing of the drug's effects changes in the further course of the psychosis. This last point might also be of value in the differential diagnosis.

Topics: Analgesics; Cannabis; Heroin; Humans; Lysergic Acid Diethylamide; Neurocognitive Disorders; Schizophrenia; Substance-Related Disorders; Tranquilizing Agents

Clinical observation suggests that cannabis is implicated in some types of psychiatric disturbance. A record of admissions to two urban and four rural hospitals in Jamaica is examined along with details of individual cases. One-third of male admissions to the psychiatric hospital have used cannabis. Of 74 males admitted to another psychiatric service over a 12-month period, 29 had used cannabis. Ten of these patients were diagnosed as "ganja psychosis," and four others were classified as "marijuana-modified mania." At another psychiatric service, 54 of 223 admissions (24.2%) for functional psychosis presented with cannabis usage as a comtributory factor. These 54 patients included 14 and seven cases of hypomanic and depressive reactions, respectively. At three other rural general hospitals, psychiatric admissions for psychosis showed 11 of 51, seven of 18, and 39 of 75 patients, respectively, in whom cannabis was considered directly responsible. These findings lend support to the idea of causation of illness or modification of existing illness. The negative findings of controlled studies in the same country are not inconsistent. A suggested classification for adverse reactions to cannabis offered by one author is recommended, because it is in accord with common local clinical experience.

Topics: Adult; Bipolar Disorder; Cannabis; Humans; Jamaica; Male; Mental Disorders; Middle Aged; Paranoid Disorders; Psychoses, Substance-Induced; Rural Population; Schizophrenia; Substance-Related Disorders; Time Factors; Urban Population

Topics: Adolescent; Adult; Autistic Disorder; Cannabis; Delusions; Diagnosis, Differential; Female; Hallucinations; Humans; Male; Psychoses, Substance-Induced; Psychotropic Drugs; Recurrence; Schizophrenia; Schizophrenic Language; Schizophrenic Psychology; Time Factors

The authors report on schizophreniform states in juvenile drug consumers. The following psychodiagnostic instruments have been used in this investigation: a list of complaints, a self-estimation scale, a psychosis-depression-neurosis inventory (v. Zerssen), the Freiburg personality inventory (FPI, Fahrenberg, Selg and Hampel). According to clinical-psychopathological data in the course of psychosis, three groups of patients (N = 21) have been formed and defined as schizophrenia-, borderline-, intoxication-psychosis-groups. The report describes the procedure of two discriminant analyses by which the said three groups have been selected. In addition to methods of a cross section approach, the necessity of longitudinal observations is discussed by means of an own clinical example, considering also observations described in the literature.

Topics: Adolescent; Adult; Amphetamines; Cannabis; Cocaine; Diagnosis, Differential; Female; Humans; Longitudinal Studies; Lysergic Acid Diethylamide; Male; Mental Disorders; Personality Inventory; Prognosis; Psychiatric Status Rating Scales; Psychoses, Substance-Induced; Schizophrenia; Statistics as Topic; Substance-Related Disorders

Topics: Adolescent; Age Factors; Anxiety; Cannabis; Child; Child Development; Child Psychiatry; Diagnosis, Differential; Electroencephalography; Epilepsy; Female; Hallucinations; Histamine H1 Antagonists; Humans; Hypnotics and Sedatives; Male; Meprobamate; Neurocognitive Disorders; Phenols; Prognosis; Psychoses, Substance-Induced; Psychotic Disorders; Schizophrenia

Topics: Cannabis; Dose-Response Relationship, Drug; Female; Humans; Lysergic Acid Diethylamide; Male; Mental Disorders; Mescaline; MMPI; Paranoid Disorders; Regression, Psychology; Schizophrenia; Social Adjustment; Substance-Related Disorders; Surveys and Questionnaires

Topics: Adolescent; Adult; Age Factors; Amphetamine; Cannabis; Drug Interactions; Female; Hallucinogens; Humans; Lysergic Acid Diethylamide; Male; Mescaline; Personality; Psychoses, Substance-Induced; Retrospective Studies; Schizophrenia; Schizophrenic Psychology; Substance-Related Disorders

Topics: Cannabis; Hallucinogens; Humans; Schizophrenia; Schizophrenic Psychology; Substance Withdrawal Syndrome; Tranquilizing Agents

Topics: Acculturation; Attitude; Birth Order; Cannabis; Ethnicity; Female; Humans; Income; Language; Malaysia; Male; Mental Disorders; Neurotic Disorders; Personality Disorders; Residence Characteristics; Schizophrenia; Sexual Dysfunction, Physiological; Social Adjustment; Social Change; Social Class; Students; Substance-Related Disorders

Topics: Acute Disease; Adolescent; Adult; Age Factors; Cannabis; Criminal Psychology; Dose-Response Relationship, Drug; Female; Humans; India; Male; Medical Records; Mental Disorders; Middle Aged; Motivation; Paranoid Disorders; Phytotherapy; Psychoses, Substance-Induced; Remission, Spontaneous; Schizophrenia; Substance-Related Disorders

Topics: Achievement; Adolescent; Adult; Amphetamine; Attitude to Health; Cannabis; Diagnosis, Differential; Female; Humans; Interview, Psychological; Lysergic Acid Diethylamide; Male; Medical Records; Psychoses, Substance-Induced; Schizophrenia; Social Behavior; Socialization; Substance-Related Disorders

Topics: Amphetamine; Cannabis; Female; Humans; Lysergic Acid Diethylamide; Male; Opium; Psychoses, Substance-Induced; Schizophrenia; Tranquilizing Agents

Topics: Adult; Alcoholic Intoxication; Cannabis; Child Behavior Disorders; Family; Female; Humans; Morphine Dependence; Projective Techniques; Schizophrenia; Social Adjustment; Substance-Related Disorders; Suicide

Topics: Adolescent; Adult; Amphetamine; Auditory Perception; Cannabis; Ethanol; Female; Hallucinations; Hallucinogens; Humans; Interview, Psychological; Lysergic Acid Diethylamide; Male; Mescaline; Middle Aged; Morphine; Schizophrenia; Schizophrenic Psychology; Substance-Related Disorders; Touch; Visual Perception

Topics: Adult; Cannabis; Cognition Disorders; Ethanol; Germany, West; Humans; International Cooperation; Legislation, Drug; Lysergic Acid Diethylamide; Male; Mental Disorders; Military Medicine; Military Personnel; Psychoses, Substance-Induced; Schizophrenia; Schizotypal Personality Disorder; Substance-Related Disorders; United States

Topics: Adolescent; Adult; Bipolar Disorder; Cannabis; Chronic Disease; Diagnosis, Differential; Female; Hospitals, Psychiatric; Humans; Male; Medical Records; Neurotic Disorders; Psychoses, Substance-Induced; Recurrence; Remission, Spontaneous; Schizophrenia; Substance-Related Disorders; Sweden

Topics: Adolescent; Adult; Amphetamine; Cannabis; Chronic Disease; Cognition Disorders; Female; Hallucinogens; Humans; Lysergic Acid Diethylamide; Male; Personality Disorders; Psychoses, Substance-Induced; Rorschach Test; Schizophrenia; Schizophrenic Psychology; Substance-Related Disorders; Thinking; Time Factors

Topics: Adult; Cannabis; Diagnosis, Differential; Humans; Male; Narcotics; Schizophrenia; Substance-Related Disorders

Topics: Amphetamine; Cannabis; Chromosome Aberrations; Drug Synergism; Female; Heroin; Humans; Lysergic Acid Diethylamide; Male; Phenothiazines; Radiation Effects; Schizophrenia; Substance-Related Disorders

Topics: Adolescent; Adult; Cannabis; Electroencephalography; Female; Humans; Male; Psychoses, Substance-Induced; Schizophrenia; Substance-Related Disorders

Topics: Adolescent; Affect; Cannabis; Family Characteristics; Follow-Up Studies; Hallucinations; Humans; Juvenile Delinquency; Memory, Short-Term; Motor Skills; Perception; Personality; Reaction Time; Schizophrenia; Social Adjustment; Socialization; Socioeconomic Factors; Substance-Related Disorders; Sweden; Therapeutic Community; Thinking

Topics: Adolescent; Adult; Age Factors; Amphetamine; Barbiturates; Cannabis; Ethnicity; Family Characteristics; Female; Heroin; Humans; Intelligence Tests; Lysergic Acid Diethylamide; Male; Mental Disorders; New York; Personality Disorders; Psychological Tests; Schizophrenia; Sex Factors; Sexual Behavior; Social Class; Substance-Related Disorders

Topics: Adjustment Disorders; Adolescent; Adult; Cannabis; Chlordiazepoxide; Chlorpromazine; Depression; Female; Hallucinogens; Humans; Male; Mental Disorders; Middle Aged; Psychoses, Substance-Induced; Psychotherapy; Schizophrenia; Substance-Related Disorders

Topics: Adolescent; Adult; Cannabis; Depression; Female; Hallucinations; Hospitalization; Humans; Male; Paranoid Disorders; Psychoses, Substance-Induced; Psychotic Disorders; Schizophrenia; Substance-Related Disorders; Time Factors

Topics: Adolescent; Adult; Cannabis; Diagnosis, Differential; Female; Humans; Male; Psychoses, Substance-Induced; Schizophrenia; Substance-Related Disorders

Topics: Amphetamine; Barbiturates; Cannabis; Child Behavior Disorders; Crime; Depression; Humans; Hyperkinesis; Legislation, Drug; Lysergic Acid Diethylamide; Narcolepsy; Paranoid Disorders; Psychology, Adolescent; Psychoses, Substance-Induced; Psychotherapy; Schizophrenia; Social Behavior; Substance Withdrawal Syndrome; Substance-Related Disorders

Topics: Acute Disease; Adult; Cannabis; Climate; Diagnosis, Differential; Humans; Male; Paranoid Disorders; Psychoses, Substance-Induced; Schizophrenia; Vietnam

Topics: Adolescent; Adult; Aggression; Amphetamine; Barbiturates; Cannabis; Catatonia; Chronic Disease; Dissociative Disorders; Female; Heroin; Humans; Juvenile Delinquency; Lysergic Acid Diethylamide; Male; Paranoid Disorders; Personality Disorders; Psychoses, Substance-Induced; Schizophrenia; Social Class; Student Dropouts; Substance-Related Disorders

Topics: Cannabis; Humans; New York City; Psychoses, Substance-Induced; Schizophrenia; Smoking; Statistics as Topic; Substance-Related Disorders

Topics: Adolescent; Adult; Cannabis; Depression; Female; Humans; Male; Personality Disorders; Psychoses, Substance-Induced; Schizophrenia; Substance-Related Disorders

Topics: Adolescent; Cannabis; Drug and Narcotic Control; Humans; Schizophrenia; Substance-Related Disorders; United States

Topics: Adult; Alcoholism; Anxiety; Cannabis; Combat Disorders; Emotions; Environment; Hospitals, Psychiatric; Humans; Interpersonal Relations; Male; Mental Disorders; Middle Aged; Milieu Therapy; Military Psychiatry; Motivation; Personality Disorders; Psychoses, Substance-Induced; Psychotic Disorders; Schizophrenia; Social Work, Psychiatric; Substance-Related Disorders; Vietnam; Warfare

Topics: Adolescent; Adult; Cannabis; Female; Humans; Male; Personality Disorders; Psychoses, Substance-Induced; Schizophrenia; Substance-Related Disorders

Chromosome studies of persons exposed to lysergic acid diethylamide, either self-administered or received during medical therapy, failed to demonstrate significant chromosomal damage.

Topics: Adult; Antisocial Personality Disorder; Cannabis; Chromosome Aberrations; Chromosomes; Culture Techniques; Female; Hallucinogens; Humans; Leukocytes; Lysergic Acid Diethylamide; Male; Middle Aged; Psychoses, Substance-Induced; Schizophrenia; Tryptamines

Topics: Adolescent; Adult; Affective Symptoms; Age Factors; Aged; Anxiety Disorders; Cannabis; Child; Child Behavior Disorders; Child, Preschool; Egypt; Enuresis; Epilepsy; Family Characteristics; Female; Humans; Hypochondriasis; Hysteria; Infant; Male; Mental Disorders; Middle Aged; Obsessive-Compulsive Disorder; Occupations; Personality Disorders; Schizophrenia; Sex Factors; Social Class; Stuttering; Substance-Related Disorders

Topics: Adult; Age Factors; Amphetamine; Antisocial Personality Disorder; Antitussive Agents; Barbiturates; Cannabis; Cocaine; Crime; Depression; Euphoria; Female; Glutethimide; Hallucinogens; Hospitalization; Hospitals, Psychiatric; Humans; Lysergic Acid Diethylamide; Male; Mental Disorders; Morphine Dependence; Motivation; Personality Disorders; Schizophrenia; Sex Factors; Substance-Related Disorders; Trichloroethylene

Topics: Acting Out; Anxiety; Cannabis; Humans; Lysergic Acid Diethylamide; Paranoid Disorders; Psychology, Adolescent; Psychoses, Substance-Induced; Schizophrenia; Social Values; Students; Substance-Related Disorders; United States

Topics: Adult; Anxiety; Brain Diseases; Cannabis; Delusions; Depression; Fear; Humans; Paranoid Disorders; Psychoses, Substance-Induced; Schizophrenia; Students; Substance-Related Disorders; Universities

Topics: Cannabinoids; Cannabis; Humans; Psychoses, Substance-Induced; Psychotic Disorders; Schizophrenia