anandamide and Schizophrenia

Recent years have yielded significant advances in our understanding of microglia, the immune cells of the central nervous system (CNS). Microglia are key players in CNS development, immune surveillance, and the maintenance of proper neuronal function throughout life. In the healthy brain, homeostatic microglia have a unique molecular signature. In neurological diseases, microglia become activated and adopt distinct transcriptomic signatures, including disease-associated microglia (DAM) implicated in neurodegenerative disorders. Homeostatic microglia synthesise the endogenous cannabinoids 2-arachidonoylglycerol and anandamide and express the cannabinoid receptors CB1 and CB2 at constitutively low levels. Upon activation, microglia significantly increase their synthesis of endocannabinoids and upregulate their expression of CB2 receptors, which promote a protective microglial phenotype by enhancing their production of neuroprotective factors and reducing their production of pro-inflammatory factors. Here, we summarise the effects of the microglial cannabinoid system in the CNS demyelinating disease multiple sclerosis, the neurodegenerative diseases Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis, chronic inflammatory and neuropathic pain, and psychiatric disorders including depression, anxiety and schizophrenia. We discuss the therapeutic potential of cannabinoids in regulating microglial activity and highlight the need to further investigate their specific microglia-dependent immunomodulatory effects.

Topics: Alzheimer Disease; Amyotrophic Lateral Sclerosis; Anxiety Disorders; Arachidonic Acids; Chronic Pain; Depressive Disorder; Endocannabinoids; Glycerides; Humans; Mental Disorders; Microglia; Multiple Sclerosis; Neuralgia; Neurodegenerative Diseases; Parkinson Disease; Polyunsaturated Alkamides; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Schizophrenia

The endocannabinoid system (ECS) is a group of neuromodulatory lipids, enzymes, and receptors involved in numerous behavioral and physiological processes such as mood, memory, and appetite. Recently, longitudinal and postmortem studies have shown that the ECS might be involved in neuropsychiatric disorders like schizophrenia. However, despite the large amount of research, our knowledge of the ECS and its implication in this debilitating disorder is still largely limited. This review aims at providing a comprehensive overview of the current state of knowledge of the ECS in schizophrenia and presenting some potential antipsychotic compounds that modulate this system. Findings from animal and human studies, and their implications for pharmacotherapy, will be integrated and discussed in this paper. A closer look will be given at the roles of the cannabinoid receptors type 1 (CB

Topics: Animals; Antipsychotic Agents; Arachidonic Acids; Cannabinoid Receptor Modulators; Endocannabinoids; Humans; Polyunsaturated Alkamides; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Schizophrenia

The endocannabinoid system (ECS) is a widespread neuromodulatory system that plays important roles in central nervous system development, synaptic plasticity, and the response to endogenous and environmental insults. The ECS comprises cannabinoid receptors, endogenous cannabinoids (endocannabinoids), and the enzymes responsible for the synthesis and degradation of the endocannabinoids. The most abundant cannabinoid receptors are the CB1 cannabinoid receptors; however, CB2 cannabinoid receptors, transient receptor potential channels, and peroxisome proliferator activated receptors are also engaged by some cannabinoids. Exogenous cannabinoids, such as tetrahydrocannabinol, produce their biological effects through their interactions with cannabinoid receptors. The best-studied endogenous cannabinoids are 2-arachidonoyl glycerol and arachidonoyl ethanolamide (anandamide). Despite similarities in chemical structure, 2-arachidonoyl glycerol and anandamide are synthesized and degraded by distinct enzymatic pathways, which impart fundamentally different physiologic and pathophysiologic roles to these two endocannabinoids. As a result of the pervasive social use of cannabis and the involvement of endocannabinoids in a multitude of biological processes, much has been learned about the physiologic and pathophysiologic roles of the ECS. This review provides an introduction to the ECS with an emphasis on its role in synaptic plasticity and how the ECS is perturbed in schizophrenia.

Topics: Arachidonic Acids; Cannabinoid Receptor Agonists; Dronabinol; Endocannabinoids; Glycerides; Humans; Neuronal Plasticity; Polyunsaturated Alkamides; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Schizophrenia

Delta(9)-Tetrahydrocannabinol (Delta(9)-THC), the principal psychoactive constituent of the Cannabis sativa plant, and other agonists at the central cannabinoid (CB(1)) receptor may induce characteristic psychomotor effects, psychotic reactions and cognitive impairment resembling schizophrenia. These effects of Delta(9)-THC can be reduced in animal and human models of psychopathology by two exogenous cannabinoids, cannabidiol (CBD) and SR141716. CBD is the second most abundant constituent of Cannabis sativa that has weak partial antagonistic properties at the CB(1) receptor. CBD inhibits the reuptake and hydrolysis of anandamide, the most important endogenous CB(1) receptor agonist, and exhibits neuroprotective antioxidant activity. SR141716 is a potent and selective CB(1) receptor antagonist. Since both CBD and SR141716 can reverse many of the biochemical, physiological and behavioural effects of CB(1) receptor agonists, it has been proposed that both CBD and SR141716 have antipsychotic properties. Various experimental studies in animals, healthy human volunteers, and schizophrenic patients support this notion. Moreover, recent studies suggest that cannabinoids such as CBD and SR141716 have a pharmacological profile similar to that of atypical antipsychotic drugs. In this review, both preclinical and clinical studies investigating the potential antipsychotic effects of both CBD and SR141716 are presented together with the possible underlying mechanisms of action.

Topics: Animals; Antipsychotic Agents; Arachidonic Acids; Cannabidiol; Endocannabinoids; Humans; Memory; Piperidines; Polyunsaturated Alkamides; Proto-Oncogene Proteins c-fos; Pyrazoles; Receptor, Cannabinoid, CB1; Rimonabant; Schizophrenia; Sensory Gating

Cannabinoids represent one of the most widely used hallucinogenic drugs and induce profound alterations in sensory perception and emotional processing. Similarly, the dopamine (DA) neurotransmitter system is critical for the central processing of emotion and motivation. Functional disturbances in either of these neurotransmitter systems are well-established correlates of the psychopathological symptoms and behavioral manifestations observed in addiction and schizophrenia. Increasing evidence from the anatomical, pharmacological and behavioral neuroscience fields points to complex functional interactions between these receptor systems at the anatomical, pharmacological and neural systems levels. An important question relates to whether these systems act in an orchestrated manner to produce the emotional processing and sensory perception deficits underlying addiction and schizophrenia. This review describes evidence for functional neural interactions between cannabinoid and DA receptor systems and how disturbances in this neural circuitry may underlie the aberrant emotional learning and processing observed in disorders such as addiction and schizophrenia.

Topics: Amygdala; Animals; Appetitive Behavior; Arachidonic Acids; Association Learning; Cannabinoids; Central Nervous System Stimulants; Dopamine; Emotions; Endocannabinoids; gamma-Aminobutyric Acid; Humans; Interneurons; Models, Neurological; Models, Psychological; Motivation; Nerve Net; Perception; Polyunsaturated Alkamides; Prefrontal Cortex; Pyramidal Cells; Rats; Receptor, Cannabinoid, CB1; Receptors, Cannabinoid; Receptors, Dopamine; Reward; Schizophrenia; Sensation; Substance-Related Disorders; Ventral Tegmental Area

Cannabidiol is a component of marijuana that does not activate cannabinoid receptors, but moderately inhibits the degradation of the endocannabinoid anandamide. We previously reported that an elevation of anandamide levels in cerebrospinal fluid inversely correlated to psychotic symptoms. Furthermore, enhanced anandamide signaling let to a lower transition rate from initial prodromal states into frank psychosis as well as postponed transition. In our translational approach, we performed a double-blind, randomized clinical trial of cannabidiol vs amisulpride, a potent antipsychotic, in acute schizophrenia to evaluate the clinical relevance of our initial findings. Either treatment was safe and led to significant clinical improvement, but cannabidiol displayed a markedly superior side-effect profile. Moreover, cannabidiol treatment was accompanied by a significant increase in serum anandamide levels, which was significantly associated with clinical improvement. The results suggest that inhibition of anandamide deactivation may contribute to the antipsychotic effects of cannabidiol potentially representing a completely new mechanism in the treatment of schizophrenia.

Topics: Acute Disease; Adult; Amides; Amisulpride; Antipsychotic Agents; Arachidonic Acids; Cannabidiol; Double-Blind Method; Drug Therapy, Combination; Endocannabinoids; Ethanolamines; Female; Humans; Male; Oleic Acids; Palmitic Acids; Polyunsaturated Alkamides; Psychiatric Status Rating Scales; Schizophrenia; Schizophrenic Psychology; Signal Transduction; Sulpiride; Young Adult

Social withdrawal in the sub-chronic phencyclidine (PCP) rat model, a behavioral correlate of the negative symptoms of schizophrenia, results from deficits in brain endocannabinoid transmission. As cannabis intake has been shown to affect negatively the course and expression of psychosis, we tested whether the beneficial effects of endocannabinoid-mediated CB1 activation on social withdrawal in PCP-treated rats (5 mg/kg, twice daily for 7 days)also occurred after administration of Δ9-tetrahydrocannabinol (THC; 0.1, 0.3, 1.0 mg/kg, i.p.). In addition, we assessed whether THC affected two correlates of positive symptoms: 1) motor activity induced by d-amphetamine (0.5 mg/kg, i.p.), and 2) dopamine neuron population activity in the ventral tegmental area (VTA). After the motor activity test, the brains from d-amphetamine-treated animals were collected and processed for measurements of endocannabinoids and activation of Akt/GSK3β, two molecular markers involved in the pathophysiology of schizophrenia. In control rats, THC dose-dependently produced social interaction deficits and aberrant VTA dopamine neuron population activity similar to those observed in PCP-treated animals. In PCP-treated rats, only the lowest dose of THC reversed PCP-induced deficits, as well as PCP-induced elevation of the endocannabinoid anandamide (AEA) in the nucleus accumbens. Last, THC activated the Akt/GSK3β pathway dose-dependently in both control and PCP-treated animals. Taken together, these data suggest that only low doses of THC have beneficial effects on behavioral, neurochemical and electrophysiological correlates of schizophrenia symptoms. This observation may shed some light on the controversial hypothesis of marijuana use as self-medication in schizophrenic patients.

Topics: Animals; Arachidonic Acids; Disease Models, Animal; Dronabinol; Endocannabinoids; Glycogen Synthase Kinase 3 beta; Male; Motor Activity; Neurons; Phencyclidine; Polyunsaturated Alkamides; Proto-Oncogene Proteins c-akt; Rats; Rats, Wistar; Schizophrenia; Signal Transduction; Ventral Tegmental Area

Epidemiological and experimental evidence suggests that the endocannabinoid system plays a pathophysiological role in schizophrenia. This is reflected by elevated cerebrospinal levels of the endocannabinoid anandamide in schizophrenia and its initial prodromal states.. We analyzed plasma concentrations of anandamide, 2-arachidonoyl-sn-glycerol, palmitoylethanolamide and oleoylethanolamide from 25 twin pairs discordant for schizophrenia, six discordant for bipolar disorder and eight healthy twin pairs to determine hereditary traits.. Twin pairs discordant for schizophrenia or bipolar disorder had significantly higher levels of anandamide and palmitoylethanolamide compared to healthy twins (both P < 0.002). Non-affected twins discordant for schizophrenia, who developed a psychotic disorder within 5 years follow-up showed lower anandamide (P = 0.042) and 2-arachidonoyl-sn-glycerol levels (P = 0.049) than twins who remained healthy.. We suggest that the protective upregulation of endocannabinoid signalling reflects either a hereditary trait or mirrors a modulating response to genetically influenced cerebral function involving, e.g., other neurotransmitters or energy metabolism.

Topics: Adult; Amides; Arachidonic Acids; Bipolar Disorder; Endocannabinoids; Ethanolamines; Female; Genetic Predisposition to Disease; Glycerides; Humans; Male; Middle Aged; Palmitic Acids; Polyunsaturated Alkamides; Prodromal Symptoms; Psychotic Disorders; Schizophrenia; Signal Transduction; Up-Regulation; Young Adult

In agreement with the neurodevelopmental hypothesis of schizophrenia, prenatal exposure of rats to the antimitotic agent methylazoxymethanol acetate (MAM) at gestational day 17 produced long-lasting behavioral alterations such as social withdrawal and cognitive impairment in the social interaction test and in the novel object recognition test, respectively. At the molecular level, an increased cannabinoid receptor type-1 (CB1) mRNA and protein expression, which might be due to reduction in DNA methylation at the gene promoter in the prefrontal cortex (PFC), coincided with deficits in the social interaction test and in the novel object recognition test in MAM rats. Both the schizophrenia-like phenotype and altered transcriptional regulation of CB1 receptors were reversed by peripubertal treatment (from PND 19 to PND 39) with the non-psychotropic phytocannabinoid cannabidiol (30 mg/kg/day), or, in part, by treatment with the cannabinoid CB1 receptor antagonist/inverse agonist AM251 (0.5 mg/kg/day), but not with haloperidol (0.6 mg/kg/day). These results suggest that early treatment with cannabidiol may prevent both the appearance of schizophrenia-like deficits as well as CB1 alterations in the PFC at adulthood, supporting that peripubertal cannabidiol treatment might be protective against MAM insult.

Topics: Amides; Animals; Arachidonic Acids; Cannabidiol; Disease Models, Animal; Endocannabinoids; Ethanolamines; Female; Glycerides; Hippocampus; Interpersonal Relations; Male; Methylazoxymethanol Acetate; Motor Activity; Oleic Acids; Palmitic Acids; Piperidines; Polyunsaturated Alkamides; Prefrontal Cortex; Pregnancy; Prenatal Exposure Delayed Effects; Puberty; Pyrazoles; Rats; Receptor, Cannabinoid, CB1; Recognition, Psychology; RNA, Messenger; Schizophrenia

Binocular depth inversion illusion (BDII) represents an illusion of visual perception that involves higher-order visual and cognitive processes. Its impairment has been linked to psychotic conditions and identified as a marker for at-risk mental states. The endogenous cannabinoid system (ECS) is involved in various neurophysiological processes. One of its key components, anandamide, is involved in the pathophysiology of schizophrenia. Little is known about its impact on BDII alterations. Therefore, we explored associations between BDII and anandamide levels.. BDII was conducted and blood and CSF were taken in 28 first-episode antipsychotic-naïve schizophrenia (SZ) patients and 81 healthy controls (HC). Serum and CSF anandamide levels were determined by high-performance liquid chromatography/mass spectrometry.. BDII scores were significantly elevated in SZ versus HC, indicating a disruption of illusionary revision of percepts in SZ. Anandamide levels were significantly higher in CSF of SZ compared to HC, while serum anandamide was not. However, we found specific association differences of anandamide levels and BDII scores between schizophrenia patients and controls in serum.. These findings support the hypothesis of an involvement of anandamide in cognitive processes impaired in schizophrenia and are consistent with a protective effect of elevated anandamide levels herein.

Topics: Adult; Arachidonic Acids; Depth Perception; Endocannabinoids; Female; Humans; Illusions; Male; Polyunsaturated Alkamides; Schizophrenia; Visual Perception; Young Adult

Cannabis use has been associated with an increased risk to develop schizophrenia as well as symptom exacerbation in patients. In contrast, clinical studies have revealed an inverse relationship between the cerebrospinal fluid levels of the endocannabinoid anandamide and symptom severity, suggesting a therapeutic potential for endocannabinoid-enhancing drugs. Indeed, preclinical studies have shown that these drugs can reverse distinct behavioral deficits in a rodent model of schizophrenia. The mechanisms underlying the differences between exogenous and endogenous cannabinoid administration are currently unknown. Using the phencyclidine (PCP) rat model of schizophrenia, we compared the effects on neuronal activity of systematic administration of delta-9-tetrahydrocannabinol (THC) with the fatty acid amide hydrolase inhibitor URB597. Specifically, we found that the inhibitory response in the prefrontal cortex to THC administration was absent in PCP-treated rats. In contrast, an augmented response to endocannabinoid upregulation was observed in the prefrontal cortex of PCP-treated rats. Interestingly, differential effects were also observed at the neuronal population level, as endocannabinoid upregulation induced opposite effects on coordinated activity when compared with THC. Such information is important for understanding why marijuana and synthetic cannabinoid use may be contraindicated in schizophrenia patients while endocannabinoid enhancement may provide a novel therapeutic approach.

Topics: Animals; Arachidonic Acids; Benzamides; Carbamates; Disease Models, Animal; Dronabinol; Endocannabinoids; Hippocampus; Male; Phencyclidine; Polyunsaturated Alkamides; Prefrontal Cortex; Rats; Rats, Sprague-Dawley; Schizophrenia; Up-Regulation

Topics: Adult; Amygdala; Antipsychotic Agents; Appetite; Arachidonic Acids; Benzodiazepines; Biomarkers; Endocannabinoids; Female; Humans; Magnetic Resonance Imaging; Male; Olanzapine; Polyunsaturated Alkamides; Schizophrenia; Treatment Outcome; Weight Gain; Young Adult

The neuronal mechanisms underlying social withdrawal, one of the core negative symptoms of schizophrenia, are not well understood. Recent studies suggest an involvement of the endocannabinoid system in the pathophysiology of schizophrenia and, in particular, of negative symptoms. We used biochemical, pharmacological, and behavioral approaches to investigate the role played by the endocannabinoid system in social withdrawal induced by sub-chronic administration of phencyclidine (PCP). Pharmacological enhancement of endocannabinoid levels via systemic administration of URB597, an inhibitor of endocannabinoid degradation, reversed social withdrawal in PCP-treated rats via stimulation of CB1 receptors, but reduced social interaction in control animals through activation of a cannabinoid/vanilloid-sensitive receptor. In addition, the potent CB agonist CP55,940 reversed PCP-induced social withdrawal in a CB₁-dependent manner, whereas pharmacological blockade of CB₁ receptors by either AM251 or SR141716 reduced the time spent in social interaction in control animals. PCP-induced social withdrawal was accompanied by a decrease of anandamide (AEA) levels in the amygdala and prefrontal cortex, and these deficits were reversed by URB597. As CB₁ receptors are predominantly expressed on GABAergic interneurons containing the anxiogenic peptide cholecystokinin (CCK), we also examined whether the PCP-induced social withdrawal resulted from deficient CB₁-mediated modulation of CCK transmission. The selective CCK2 antagonist LY225910 blocked both PCP- and AM251-induced social withdrawal, but not URB597 effect in control rats. Taken together, these findings indicate that AEA-mediated activation of CB₁ receptors is crucial for social interaction, and that PCP-induced social withdrawal results from deficient endocannabinoid transmission.

Topics: Amidohydrolases; Amygdala; Animals; Arachidonic Acids; Benzamides; Cannabinoid Receptor Agonists; Cannabinoid Receptor Antagonists; Carbamates; Cyclohexanols; Dose-Response Relationship, Drug; Endocannabinoids; Male; Phencyclidine; Piperidines; Polyunsaturated Alkamides; Prefrontal Cortex; Pyrazoles; Quinazolinones; Rats; Receptor, Cannabinoid, CB1; Receptor, Cholecystokinin B; Rimonabant; Schizophrenia; Social Behavior

Disturbances in the endogenous cannabinoid (ECB) system in schizophrenia may contribute to their enhanced sensitivity to psychoactive substances, and the beneficial effects of second-generation antipsychotics for substance abuse in schizophrenia may involve modulatory effects on ECB. To verify these two assumptions, 29 patients (24 completers) with schizophrenia and substance use disorders (SUD) were treated with quetiapine for 12 weeks, and peripheral ECB levels were measured, using high-performance liquid chromatography/mass spectrometry, in patients (weeks 0, 6 and 12) and 17 healthy volunteers. Baseline anandamide levels were significantly higher in patients, relative to controls. This result is consistent with studies describing ECB dysfunctions in schizophrenia. SUD parameters improved during treatment, but no changes in ECB occurred over time. Improvements in substance abuse were probably not mediated by modulatory effects of quetiapine on ECB. Lastly, baseline anandamide predicted endpoint SUD scores (alcohol/ cannabis). Anandamide is a potential target for medications aimed at relieving SUD in schizophrenia.

Topics: Adult; Analysis of Variance; Antipsychotic Agents; Arachidonic Acids; Cannabinoid Receptor Modulators; Chromatography, High Pressure Liquid; Diagnosis, Dual (Psychiatry); Dibenzothiazepines; Endocannabinoids; Female; Humans; Linear Models; Male; Mass Spectrometry; Middle Aged; Polyunsaturated Alkamides; Psychiatric Status Rating Scales; Quetiapine Fumarate; Schizophrenia; Schizophrenic Psychology; Substance-Related Disorders

Previous studies have shown that cerebrospinal fluid (CSF) from schizophrenic patients contains significantly higher levels of the endogenous cannabinoid anandamide than does CSF from healthy volunteers. Moreover, CSF anandamide levels correlated inversely with psychotic symptoms, suggesting that anandamide release in the central nervous system (CNS) may serve as an adaptive mechanism countering neurotransmitter abnormalities in acute psychoses. In the present study we examined whether cannabis use may alter such a mechanism.. We used liquid chromatography/mass spectrometry (LC/MS) to measure anandamide levels in serum and CSF from first-episode, antipsychotic-naïve schizophrenics (n=47) and healthy volunteers (n=81). Based on reported patterns of cannabis use and urine delta9-tetrahydrocannabinol (delta9-THC) tests, each subject group was further divided into two subgroups: 'low-frequency' and 'high-frequency' cannabis users (lifetime use < or = 5 times and > 20 times, respectively). Serum delta9-THC was investigated to determine acute use and three patients were excluded from the analysis due to detectable delta9-THC levels in serum.. Schizophrenic low-frequency cannabis users (n=25) exhibited > 10-fold higher CSF anandamide levels than did schizophrenic high-frequency users (n=19, p=0.008), healthy low-frequency (n=55, p<0.001) or high-frequency users (n=26, p<0.001). In contrast, no significant differences in serum anandamide levels were found among the four subgroups. CSF anandamide levels and disease symptoms were negatively correlated in both user groups.. The results indicate that frequent cannabis exposure may down-regulate anandamide signaling in the CNS of schizophrenic patients, but not of healthy individuals. Thus, our findings suggest that alterations in endocannabinoid signaling might be an important component of the mechanism through which cannabis impacts mental health.

Topics: Acute Disease; Adult; Arachidonic Acids; Cannabinoids; Chromatography, Liquid; Endocannabinoids; Female; Gas Chromatography-Mass Spectrometry; Humans; Male; Marijuana Abuse; Polyunsaturated Alkamides; Prevalence; Psychotic Disorders; Schizophrenia; Time Factors

Topics: Adaptation, Physiological; Adaptation, Psychological; Arachidonic Acids; Chronic Disease; Cognition Disorders; Comorbidity; Diagnosis, Dual (Psychiatry); Endocannabinoids; Humans; Life Change Events; Marijuana Smoking; Polyunsaturated Alkamides; Receptors, Nicotinic; Schizophrenia; Schizophrenic Psychology; Self Medication; Stress, Psychological

The endocannabinoids are a family of bioactive lipids that activate CB1 cannabinoid receptors in the brain and exert intense emotional and cognitive effects. Here, we have examined the role of endocannabinoid signaling in psychotic states by measuring levels of the endocannabinoid anandamide in cerebrospinal fluid (CSF) of acute paranoid-type schizophrenic patients. We found that CSF anandamide levels are eight-fold higher in antipsychotic-naive first-episode paranoid schizophrenics (n = 47) than healthy controls (n = 84), dementia patients (n = 13) or affective disorder patients (n = 22). Such an alteration is absent in schizophrenics treated with 'typical' antipsychotics (n = 37), which antagonize dopamine D2-like receptors, but not in those treated with 'atypical' antipsychotics (n = 34), which preferentially antagonize 5HT(2A) receptors. Furthermore, we found that, in nonmedicated acute schizophrenics, CSF anandamide is negatively correlated with psychotic symptoms (rS = -0.452, P = 0.001). The results suggest that anandamide elevation in acute paranoid schizophrenia may reflect a compensatory adaptation to the disease state.

Topics: Adult; Aged; Aged, 80 and over; Arachidonic Acids; Cohort Studies; Endocannabinoids; Female; Humans; Male; Middle Aged; Polyunsaturated Alkamides; Psychotic Disorders; Schizophrenia; Statistics, Nonparametric

Evidence suggests that cannabinoid receptors, the pharmacologcial target of cannabis-derived drugs, and their accompanying system of endogenous activators may be dysfunctional in schizophrenia. To test this hypothesis, we examined whether endogenous cannabinoid concentrations in cerebrospinal fluid of schizophrenic patients are altered compared to nonschizophrenic controls. Endogenous cannabinoids were purified from cerebrospinal fluid of 10 patients with schizophrenia and 11 non-schizophrenic controls by high-performance liquid chromatography, and quantified by isotope dilution gas-chromatography/mass-spectrometry. Cerebrospinal concentrations of two endogenous cannabinoids (anandamide and palmitylethanolamide) were significantly higher in schizophrenic patients than non-schizophrenic controls (p < 0.05). By contrast, levels of 2-arachidonylglycerol, another endogenous cannabinoid lipid, were below detection in both groups. The findings did not seem attributable to gender, age or medication. Elevated anandamide and palmitylethanolamide levels in cerebrospinal fluid of schizophrenic patients may reflect an imbalance in endogenous cannabinoid signaling, which may contribute to the pathogenesis of schizophrenia.

Topics: Adult; Amides; Arachidonic Acids; Cannabinoids; Chromatography, High Pressure Liquid; Endocannabinoids; Ethanolamines; Female; Gas Chromatography-Mass Spectrometry; Humans; Male; Middle Aged; Palmitic Acids; Polyunsaturated Alkamides; Schizophrenia

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