clozapine and Memory-Disorders

This meta-analytic review examines the efficacy of antipsychotic medications in ameliorating schizophrenia-related long-term memory (LTM) impairments. Twenty-three studies were reviewed that compared schizophrenia spectrum patients treated (a) with atypical versus typical antipsychotic medications, or (b) with various atypical treatments. In 17 atypical versus typical trials aggregating 939 participants, superior overall (verbal and nonverbal) LTM was detected in patients assigned to atypical trials. However, this difference was small (effect size estimate (ES) 0.17; 95% Confidence Interval (CI) 0.04 to 0.31) and specific to certain atypical treatments. Relative to typical antipsychotic trials, LTM superiority was marginally significant for risperidone trials (ES 0.20; 95% CI -0.03 to 0.44) and significant for olanzapine trials (ES 0.29; 95% CI 0.08 to 0.49). In contrast, clozapine trials did not produce a LTM advantage over typical trials (ES -0.06; 95% CI -0.35 to 0.23). Due to the lack of available studies, the effect of quetiapine was indeterminate. Direct comparison between atypical trials revealed a similar effect pattern. A marginally significant superiority in overall LTM was detected for risperidone and olanzapine compared to clozapine (ES 0.28; 95% CI -0.04 to 0.59), which reached significance for verbal LTM (ES 0.36; 95% CI 0.04 to 0.67). Finally, the beneficial impact of antipsychotic medications emerged as a function of differences in the anticholinergic properties of the treatment arms being compared.

Topics: Antipsychotic Agents; Benzodiazepines; Clozapine; Humans; Memory Disorders; Olanzapine; Retention, Psychology; Risperidone; Schizophrenia

In a recent placebo-controlled, double-blind crossover trial (n = 52), significant beneficial effects on memory (d = 0.30) and negative symptoms (d = 0.29) were found after 12 weeks of memantine augmentation in patients with clozapine-refractory schizophrenia. In this open-label 1-year extension study we report the long-term effects and tolerability of memantine add-on therapy to clozapine.. Completers of the first trial who experienced beneficial effects during 12 weeks of memantine treatment received memantine for 1 year. Primary endpoints were memory and executive function using the Cambridge Neuropsychological Test Automated Battery, the Positive and Negative Syndrome Scale (PANSS), and the Clinical Global Impression Severity Scale (CGI-S).. Of 31 randomized controlled trial completers who experienced beneficial effects from memantine, 24 received memantine for 1 year. The small improvement in memory found in the memantine condition in the placebo-controlled trial remained stable in the extension study. Executive function did not improve. After 26 weeks of memantine add-on therapy to clozapine, PANSS negative symptoms (r = 0.53), PANSS positive symptoms (r = 0.50) and PANSS total symptoms (r = 0.54) significantly improved. Even further significant improvement in all these measures was observed between 26 weeks and 52 weeks of memantine, with effect sizes varying from 0.39 to 0.51. CGI-S showed a non-significant moderate improvement at 26 weeks (r = 0.36) and 52 weeks (r = 0.34). Memantine was well tolerated without serious adverse effects.. In the 1-year extension phase the favourable effect of adjunctive memantine on memory was sustained and we observed further improvement of negative, positive and overall symptoms in patients with clozapine-treated refractory schizophrenia.

Topics: Adult; Antipsychotic Agents; Clozapine; Cognitive Dysfunction; Drug Resistance; Drug Synergism; Drug Therapy, Combination; Excitatory Amino Acid Antagonists; Executive Function; Female; Follow-Up Studies; Humans; Male; Memantine; Memory Disorders; Middle Aged; Schizophrenia

Dysfunction of neuroplasticity due to N-methyl-d-aspartate (NMDA) receptor hypofunction may be a causal factor for memory and executive dysfunctioning in schizophrenia. Deregulation of NMDA transmission in the prefrontal cortex may also explain negative and positive symptoms. Clozapine augmentation with memantine targets altered NMDA receptor-mediated neurotransmission in schizophrenia and showed substantial beneficial effects on several symptom domains in a small proof-of-concept study. We evaluate effects of memantine add-on treatment to clozapine for memory and executive function, and negative and positive symptoms in schizophrenia.. Clozapine-treated patients with refractory schizophrenia were randomly assigned to 12 weeks of double-blind adjunctive treatment with memantine (n = 26) or placebo (n = 26). Crossover occurred after a 2-week placebo wash-out period. Primary endpoints were change from baseline to 12 weeks treatment and 14 weeks to 26 weeks treatment on memory and executive function using the Cambridge Neuropsychological Test Automated Battery (CANTAB), Positive and Negative Syndrome Scale (PANSS), and Clinical Global Impression Severity Scale (CGI-S). Side effects were assessed using the Liverpool University Neuroleptic Side-Effect Rating Scale.. When compared with placebo, memantine improved a composite memory score comprising verbal recognition memory and paired associates learning task scores on the CANTAB (effect size = 0.30) and PANSS negative subscale score (effect size = 0.29). Side effects were mild and transient.. In patients with clozapine-treated refractory schizophrenia, memantine addition significantly improved verbal and visual memory and negative symptoms without serious adverse effects. These results justify further investigations on long-term memantine augmentation to clozapine in treatment-resistant schizophrenia.

Topics: Adult; Antipsychotic Agents; Clozapine; Cognitive Dysfunction; Cross-Over Studies; Double-Blind Method; Drug Resistance; Drug Therapy, Combination; Excitatory Amino Acid Antagonists; Female; Humans; Male; Memantine; Memory Disorders; Middle Aged; Outcome Assessment, Health Care; Schizophrenia

Recent data have suggested few differences in the cognitive effects of antipsychotic medications. However, assessment of such effects can be complex, due to a number of factors. Clozapine has previously shown greater clinical and lesser cognitive benefits than other atypicals. This study compared the cognitive benefits of clozapine and ziprasidone in schizophrenia patients (n=130) with a history of either failure to respond to or intolerance of previous adequate antipsychotic treatments.. Patients were randomized (double-blind) to either clozapine or ziprasidone in a single country (Italy), multi-site trial. The cognitive assessments examined episodic memory (RAVLT), executive functioning (Stroop test), and processing speed (Trail-making test (TMT) Parts A and B).. Analyses found statistically significant within-group improvements for ziprasidone in learning and delayed recall on the RAVLT and on TMT Parts A and B. Clozapine-treated patients improved on the RAVLT, but not on the TMT. A composite cognitive score improved from baseline in both groups, but the improvements were significantly larger in the ziprasidone group (p=.029).. These results indicated that cognitive functioning improved following treatment with ziprasidone in patients with a history of either treatment resistance or intolerance, and that the effects are comparable or greater than those observed with clozapine. One interpretation of these findings is that clozapine treatment interferes with the performance benefits associated with practice.

Topics: Adult; Antipsychotic Agents; Clozapine; Cognition Disorders; Double-Blind Method; Drug Resistance; Drug Tolerance; Female; Humans; Italy; Male; Memory Disorders; Neuropsychological Tests; Piperazines; Placebos; Schizophrenia; Schizophrenic Psychology; Thiazoles; Trail Making Test; Treatment Outcome

The purpose of this investigation was to evaluate the effects of clozapine and risperidone on spatial working memory in patients with schizophrenia.. Spatial working memory performance was evaluated at baseline and after 17 and 29 weeks in 97 patients with schizophrenia participating in a multisite trial.. Compared with baseline performance while receiving conventional antipsychotic medication, risperidone improved, and clozapine worsened, spatial working memory performance.. The differential effects of these medications on spatial working memory may be due to the anticholinergic effects of clozapine and prefrontal dopamine-enhancing effects of risperidone.

Topics: Adult; Antipsychotic Agents; Brief Psychiatric Rating Scale; Clozapine; Diagnosis, Computer-Assisted; Double-Blind Method; Female; Follow-Up Studies; Humans; Male; Memory; Memory Disorders; Middle Aged; Neuropsychological Tests; Prefrontal Cortex; Psychomotor Performance; Psychotic Disorders; Risperidone; Schizophrenia; Schizophrenic Psychology; Space Perception

The deficiency of the gaseous molecule nitric oxide (NO) seems to be critically involved in the pathogenesis of schizophrenia. Thus, molecules that can normalize NO levels, as are NO donors, might be of utility for the medication of this psychiatric disease. The aim of the present study was to detect the ability of the NO donor molsidomine to reduce schizophrenia-like impairments produced by the blockade of the N-methyl-D-aspartate (NMDA) receptor in rats. Molsidomine's ability to attenuate social withdrawal and spatial recognition memory deficits induced by the NMDA receptor antagonist ketamine were assessed using the social interaction and the object location test, respectively. Further, the efficacy of the combination of sub-effective doses of molsidomine with sub-effective doses of the atypical antipsychotic clozapine in alleviating non-spatial recognition memory deficits was evaluated utilizing the object recognition task. Molsidomine (2 and 4 mg/kg) attenuated social withdrawal and spatial recognition memory deficits induced by ketamine. Co-administration of inactive doses of molsidomine (1 mg/kg) and clozapine (0.1 mg/kg) counteracted delay-dependent and ketamine-induced non-spatial recognition memory deficits. The current findings suggest that molsidomine is sensitive to glutamate hypofunction since it attenuated behavioral impairments in animal models mimicking the negative symptoms and cognitive deficits of schizophrenia. Additionally, the present results support the potential of molsidomine as an adjunctive drug for the therapy of schizophrenia.

Topics: Animals; Clozapine; Cognition; Cognitive Dysfunction; Ketamine; Memory Disorders; Molsidomine; Nitric Oxide; Nitric Oxide Donors; Rats; Rats, Wistar; Receptors, N-Methyl-D-Aspartate; Social Isolation

Parkinson's disease (PD), classically defined as a progressive motor disorder accompanied with dopaminergic neuron loss and presence of Lewy bodies, is the second most common neurodegenerative disease. PD also has various non-classical symptoms, including cognitive impairments. In addition, inflammation and astrogliosis are recognized as an integral part of PD pathology. The hippocampus (Hipp) is a brain region involved in cognition and memory, and the neuropeptide orexin has been shown to enhance learning and memory. Previous studies show impairments in Hipp-dependent memory in a transgenic mouse model of Parkinson's disease (A53T mice), and we hypothesized that increasing orexin tone will reverse this. To test this, we subjected 3, 5, and 7-month old A53T mice to a Barnes maze and a contextual object recognition test to determine Hipp dependent memory. Inflammation and astrogliosis markers in the Hipp were assessed by immuno-fluorescence densitometry. The data show that early cognitive impairment is coupled with an increase in expression of inflammatory and astrogliosis markers. Next, in two separate experiments, mice were given intra-hippocampal injections of orexin or chemogenetic viral injections of an orexin neuron specific Designer Receptor Exclusively Activated by Designer Drug (DREADD). For the pharmacological approach mice were intracranially treated with orexin A, whereas the chemogenetic approach utilized clozapine N-oxide (CNO). Both pharmacological orexin A intervention as well as chemogenetic activation of orexin neurons ameliorated Hipp-dependent early memory impairment observed in A53T mice. This study implicates orexin in PD-associated cognitive impairment and suggests that exogenous orexin treatment and/or manipulation of endogenous orexin levels may be a potential strategy for addressing early cognitive loss in PD.

Topics: Animals; Calcium-Binding Proteins; Cell Count; Clozapine; Disease Models, Animal; Glial Fibrillary Acidic Protein; Gliosis; Hippocampus; Inflammation; Injections; Male; Maze Learning; Memory Disorders; Mice, Inbred C57BL; Mice, Transgenic; Microfilament Proteins; Orexins; Parkinson Disease; Reproducibility of Results

Alzheimer's disease (AD) is a progressive degenerative condition. In order to treat AD, the use of a "drug repositioning" or "repurposing" approach with potential disease-modifying compounds has been increased. The new generation antipsychotics are commonly used in AD and other dementias for the treatment of psychosis and behavioral symptoms, and several animal models have shown the effects of these potential disease-modifying compounds. In this study, we examined whether long-term clozapine treatment could reduce amyloid beta (Aβ) deposition and cognitive impairment in transgenic mice of AD, Tg-APPswe/PS1dE9. AD mice were fed clozapine at 20 mg/kg/day for 3 months from 4.5 months of age. Intake of clozapine improved the Aβ-induced memory impairment and suppressed Aβ levels and plaque deposition in the brain of AD mice. Clozapine upregulated Trk, brain-derived neurotrophic factor, cyclin-dependent kinase-5, and p35 in the cortex and hippocampus of AD mice and activated AMP-activated protein kinase (AMPK). As a downstream effector of AMPK, beta-secretase expression was decreased by clozapine administration. Moreover, clozapine-phosphorylated synapsin I at Ser9 and Ser549 sites in the hippocampus and cortex of AD mice, which may be involved in synaptic strength. This study suggests that as one of candidate for multi-target approach of AD treatment, clozapine is proposed as a therapeutic drug for treatment of AD patients.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Clozapine; Male; Memory Disorders; Mice; Mice, Inbred C57BL; Mice, Transgenic; Peptide Fragments; Presenilin-1

The aim of study was to investigate the effects of pyrroloquinoline quinone (PQQ) combined with d-serine on the modulation of glycine sites in the brain of rats using social recognition test. Rats were divided into seven groups (n=10) and given repeated intraperitoneal (ip) injections of saline, MK-801 (0.5mg/kg), clozapine (1mg/kg), haloperidol (0.1mg/kg), d-serine (0.8g/kg), PQQ (2.0μg/kg), or d-serine (0.4g/kg) combined with PQQ (1.0μg/kg) for seven days. A social recognition test, including assessment of time-dependent memory impairment, was performed. A non-competitive NMDA receptor antagonist, MK-801, significantly impaired social memory, and this impairment was significantly repaired with an atypical antipsychotic (clozapine) but not with a typical antipsychotic (haloperidol). Likewise, d-serine combined with PQQ significantly improved MK-801-disrupted cognition in naïve rats, whereas haloperidol was ineffective. The present results show that the co-agonist NMDA receptor treated with PQQ and d-serine enhances social memory and may be an effective approach for treating the cognitive dysfunction observed in schizophrenic patients. PQQ stimulates glycine modulatory sites by which it may antagonize indirectly by removing glycine from the synaptic cleft or by binding the unsaturated site with d-serine in the brain, providing the insights into future research of central nervous system and drug discovery.

Topics: Animals; Antipsychotic Agents; Clozapine; Dizocilpine Maleate; Drug Contamination; Drug Synergism; Glycine; Haloperidol; Male; Memory; Memory Disorders; Neuroprotective Agents; PQQ Cofactor; Rats; Rats, Sprague-Dawley; Serine; Social Behavior; Time Factors

Topics: Acetylcholine; Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Clozapine; Conditioning, Psychological; Disease Models, Animal; Fear; Glutamate Decarboxylase; Hippocampus; Interneurons; Memory Disorders; Mice; Mice, Transgenic; Neuroanatomical Tract-Tracing Techniques; Neuronal Plasticity; Somatostatin; Synapses

Disrupted-in-schizophrenia 1(DISC1) is a promising candidate susceptibility gene for a spectrum of psychiatric illnesses that share cognitive impairments in common, including schizophrenia, bipolar disorder and major depression. Here we report that DISC1 L100P homozygous mutant shows normal anxiety- and depression-like behavior, but impaired object recognition which is prevented by administration of atypical antipsychotic drug clozapine. Ca

Topics: Animals; Anxiety; Behavior, Animal; Calcium; Clozapine; Dendrites; Depression; Female; Hippocampus; Homozygote; Male; Memory Disorders; Mice, Inbred C57BL; Motor Activity; Mutation; Nerve Tissue Proteins; Neuronal Plasticity; Recognition, Psychology; Spatial Learning; Synaptic Transmission

Designer receptors exclusively activated by designer drugs (DREADDs) are novel and powerful tools to investigate discrete neuronal populations in the brain. We have used DREADDs to stimulate degenerating neurons in a Down syndrome (DS) model, Ts65Dn mice. Individuals with DS develop Alzheimer's disease (AD) neuropathology and have elevated risk for dementia starting in their 30s and 40s. Individuals with DS often exhibit working memory deficits coupled with degeneration of the locus coeruleus (LC) norepinephrine (NE) neurons. It is thought that LC degeneration precedes other AD-related neuronal loss, and LC noradrenergic integrity is important for executive function, working memory, and attention. Previous studies have shown that LC-enhancing drugs can slow the progression of AD pathology, including amyloid aggregation, oxidative stress, and inflammation. We have shown that LC degeneration in Ts65Dn mice leads to exaggerated memory loss and neuronal degeneration. We used a DREADD, hM3Dq, administered via adeno-associated virus into the LC under a synthetic promoter, PRSx8, to selectively stimulate LC neurons by exogenous administration of the inert DREADD ligand clozapine-N-oxide. DREADD stimulation of LC-NE enhanced performance in a novel object recognition task and reduced hyperactivity in Ts65Dn mice, without significant behavioral effects in controls. To confirm that the noradrenergic transmitter system was responsible for the enhanced memory function, the NE prodrug l-threo-dihydroxyphenylserine was administered in Ts65Dn and normosomic littermate control mice, and produced similar behavioral results. Thus, NE stimulation may prevent memory loss in Ts65Dn mice, and may hold promise for treatment in individuals with DS and dementia.

Topics: Animals; Antipsychotic Agents; Cell Count; Clozapine; Cross-Over Studies; Designer Drugs; Disease Models, Animal; Down Syndrome; Exploratory Behavior; Gene Expression Regulation; Humans; Locus Coeruleus; Male; Maze Learning; Memory Disorders; Mice; Mice, Neurologic Mutants; Motor Activity; Neurodegenerative Diseases; Receptor, Muscarinic M3; Serine

Accumulating evidence suggests that dysregulation of histone modification is involved in the pathogenesis and/or pathophysiology of psychiatric disorders. However, the abnormalities in histone modification in the animal model of schizophrenia and the efficacy of antipsychotics for such abnormalities remain unclear. Here, we investigated the involvement of histone modification in phencyclidine-induced behavioral abnormalities and the effects of antipsychotics on these abnormalities. After repeated phencyclidine (10 mg/kg) treatment for 14 consecutive days, mice were treated with antipsychotics (clozapine or haloperidol) or the histone deacetylase inhibitor sodium butyrate for 7 d. Repeated phencyclidine treatments induced memory impairment and social deficit in the mice. The acetylation of histone H3 at lysine 9 residues decreased in the prefrontal cortex with phencyclidine treatment, whereas the expression level of histone deacetylase 5 increased. In addition, the phosphorylation of Ca²⁺/calmodulin-dependent protein kinase II in the nucleus decreased in the prefrontal cortex of phencyclidine-treated mice. These behavioral and epigenetic changes in phencyclidine-treated mice were attenuated by clozapine and sodium butyrate but not by haloperidol. The dopamine D1 receptor antagonist SCH-23390 blocked the ameliorating effects of clozapine but not of sodium butyrate. Furthermore, clozapine and sodium butyrate attenuated the decrease in expression level of GABAergic system-related genes in the prefrontal cortex of phencyclidine-treated mice. These findings suggest that the antipsychotic effect of clozapine develops, at least in part, through epigenetic modification by activation of the dopamine D1 receptor in the prefrontal cortex.

Topics: Animals; Antipsychotic Agents; Benzazepines; Butyric Acid; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Clozapine; Dopamine Antagonists; Epigenesis, Genetic; Exploratory Behavior; Hallucinogens; Haloperidol; Histamine Antagonists; Histone Deacetylases; Histones; Male; Memory Disorders; Mice; Mice, Inbred ICR; Phencyclidine; Phencyclidine Abuse; Prefrontal Cortex; Receptors, Dopamine D1

This study combined two neurodevelopmental manipulations, neonatal MK-801 treatment and isolation rearing, to produce a 'two-hit' model and determine whether two hits induce a more robust behavioural phenotype of an animal model of aspects of schizophrenia compared with individual manipulations alone. The effect of clozapine was also assessed. Male Sprague-Dawley rats received 0.2 mg/kg MK-801 or saline intraperitoneally (i.p.) once daily on postnatal days (PNDs) 7-10 and were assigned to group or isolation rearing at weaning (PND 21). From PND 77, they received a vehicle or 5 mg/kg clozapine (i.p.) treatment regimen and were subjected to three prepulse inhibition (PPI) tests, a locomotor activity assessment and a novel object recognition task. MK-801-treated rats reared in isolation displayed robust PPI disruptions which were consistently manifested in all three tests. PPI deficits were also detected in saline-treated rats reared in isolation but not in all tests. Only the two-hit rats demonstrated hyperlocomotion and impaired object recognition memory. Clozapine restored PPI anomalies in the two-hit rats. The two-hit model showed greater psychotic-like effects than either neonatal MK-801 or isolation rearing alone. The preliminary predictive validity shown with clozapine suggests this model may be useful for predicting the efficacy of putative antipsychotics.

Topics: Akathisia, Drug-Induced; Animals; Animals, Newborn; Antipsychotic Agents; Behavior, Animal; Clozapine; Disease Models, Animal; Dizocilpine Maleate; Excitatory Amino Acid Antagonists; Exploratory Behavior; Injections, Intraperitoneal; Male; Maternal Deprivation; Memory Disorders; Neural Inhibition; Neurotoxicity Syndromes; Random Allocation; Rats; Rats, Sprague-Dawley; Receptors, N-Methyl-D-Aspartate; Schizophrenia

Marijuana (Cannabis sativa) is one of the most widely used illicit drugs in the world. Its use is associated with impairments in cognitive function. We previously reported that Δ(9)-tetrahydrocannabinol (Δ(9)-THC), the primary psychoactive component of marijuana, impaired spatial working memory in the radial maze task when injected intracortically (IC) into the medial prefrontal cortex (mPFC) of rats. Here, we used this paradigm to evaluate the involvement of prefrontal dopamine receptors in working memory disruption induced by Δ(9)-THC. Intracortical pre-treatment of animals with either the D(1)- or D(2)-like dopamine receptor antagonists SCH 23390 or clozapine, respectively, significantly reduced the number of errors rats made in the radial maze following treatment with Δ(9)-THC also administered intracortically. These results were obtained in the absence of locomotor impairment, as evidenced by the time spent in each arm a rat visited. Our findings suggest that prefrontal dopamine receptors are involved in Δ(9)-THC-induced disruption of spatial working memory. This interaction between the cannabinoid system and dopamine release in the PFC contributes to new directions in research and to treatments for cognitive dysfunctions associated with drug abuse and dependence.

Topics: Animals; Benzazepines; Clozapine; Disease Models, Animal; Dopamine Antagonists; Dronabinol; Male; Maze Learning; Memory Disorders; Prefrontal Cortex; Psychotropic Drugs; Rats; Rats, Wistar

We investigated the effects of the second generation antipsychotics olanzapine, sertindole and clozapine on visual recognition memory using the novel object recognition (NOR) test in naive and MK-801-treated animals. The effects of drug treatment on locomotion and anxiety were also determined using the open field test. Male Balb-c mice were treated with olanzapine (0.2, 0.4 and 0.6 mg/kg; i.p.), sertindole (0.63, 1.3 and 2.5mg/kg; s.c.) or clozapine (0.5 and 1mg/kg; i.p.), and cognitive deficits were induced by MK-801 (0.2mg/kg; i.p.) administration. Olanzapine treatment decreased the ratio index in the NOR test, whereas sertindole and clozapine had no effect in naive mice. MK-801-induced cognitive impairment was reversed by treatment with olanzapine, sertindole or clozapine. While olanzapine, sertindole and clozapine had no effect on the anxiety of naive mice as determined by the open field test, MK-801 significantly increased the total distance traveled, time spent in the center zone and the velocity of the animals. MK-801-induced effects on locomotion and anxiety in the open field test were reversed by olanzapine, sertindole or clozapine treatment. The results of the present study demonstrated that olanzapine, sertindole and clozapine improved cognition in MK-801 treated mice, and indicate that these drugs have a potential to improve cognition in schizophrenia.

Topics: Animals; Antipsychotic Agents; Benzodiazepines; Clozapine; Dizocilpine Maleate; Excitatory Amino Acid Antagonists; Imidazoles; Indoles; Learning; Male; Memory Disorders; Mice; Mice, Inbred BALB C; Motor Activity; Olanzapine; Recognition, Psychology; Visual Perception

Clozapine and olanzapine are antipsychotic drugs commonly used to treat schizophrenia and psychosis; however, few studies have investigated their effects on cognitive function using animal models. Thus, the effects of olanzapine and clozapine on memory acquisition, consolidation and retrieval were investigated in naive mice using a modified elevated plus maze (mEPM) task. Olanzapine (0.15 and 0.30 mg/kg) and clozapine (0.5 and 1 mg/kg) were injected intraperitoneally (i.p.) into male Balb-c mice before training, immediately after training or before the second day of the trial. Our results showed that both olanzapine and clozapine disrupted the acquisition of spatial memory. In addition, clozapine impaired the consolidation of spatial memory, while olanzapine had no effect. Furthermore, olanzapine and clozapine significantly disrupted memory retrieval in naive mice. Thus, these results at least suggest that olanzapine can be a superior treatment for schizophrenia compared to clozapine.

Topics: Animals; Antipsychotic Agents; Benzodiazepines; Clozapine; Dose-Response Relationship, Drug; Male; Maze Learning; Memory; Memory Disorders; Mice; Mice, Inbred BALB C; Olanzapine

Converging evidence indicates that prenatal exposure to immune challenge can induce long-term cognitive deficits relevant to schizophrenia. Such cognitive impairments may be related to deficient hippocampal neurogenesis at adult age.. In the present study, we sought evidence for the possibility that chronic treatment with the reference atypical antipsychotic drug clozapine may improve prenatal infection-induced cognitive dysfunctions by stimulating adult hippocampal neurogenesis.. This hypothesis was tested in a well-established mouse model of prenatal immune challenge which is based on prenatal administration of the viral mimic, polyriboinosinic-polyribocytidilic acid (PolyI:C).. We found that maternal PolyI:C (5 mg/kg, i.v.) exposure on gestation day 17 led to significant spatial working memory impairment and reduced hippocampal neurogenesis in the resulting offspring at adult age. The latter effect was apparent in postmortem immunohistochemical analyses of the cell proliferation marker bromodeoxyuridine and the microtubule-associated protein doublecortin, a marker of newborn neuronal cells. Chronic (3 weeks) administration of clozapine (5 mg/kg/day, i.p.) significantly improved the prenatal PolyI:C-induced working memory deficits, while at the same time, it negatively affected working memory performance in adult offspring born to control mothers. These bidirectional cognitive effects of clozapine were not paralleled by concomitant effects on adult hippocampal neurogenesis.. Our findings do not support the hypothesis that the atypical antipsychotic drug clozapine may influence cognitive functions by acting on adult neurogenesis in the hippocampus, regardless of whether the drug is administered to subjects with or without a neurodevelopmental predisposition to adult neuropathology.

Topics: Animals; Antipsychotic Agents; Cell Count; Clozapine; Disease Models, Animal; Female; Hippocampus; Male; Memory Disorders; Memory, Short-Term; Mice; Mice, Inbred C57BL; Neurogenesis; Polynucleotides; Pregnancy; Pregnancy Complications, Infectious; Prenatal Exposure Delayed Effects

Cognitive dysfunctions in patients suffering from schizophrenia (SZ) are also found in their unaffected parents though to a lesser degree. According to several researchers, short-term memory (STM) deficits are a potential marker of vulnerability to SZ. However, the cognitive processes underlying the observed STM deficits remain underspecified in SZ (Lee & Park, 2005). In the present study, our goal was to pinpoint those processes at play in the manifestation of STM deficits by using the paradigm of the sandwich effect (e.g., Hitch, 1975) to manipulate information load (5 vs. 7 to-be-remembered items) and distraction (control vs. sandwich) in the verbal domain. Our study comprises four groups: patients with SZ (n = 25), their unaffected parents (n = 25), and their respective healthy controls. The pattern of results indicates a generalized dysfunction of STM in patients with SZ characterized by saturation and an increased susceptibility to distraction. The impact of saturation and distraction was also observed in unaffected parents of patients with SZ to a lesser degree. The methodological strategy adopted here allowed us to show that the dysfunction of STM is genuine, can be aggravated by deficits in selective attention, and is a good candidate for further research on genetic epidemiology.

Topics: Age of Onset; Antipsychotic Agents; Attention; Clozapine; Dibenzothiazepines; Female; Humans; Male; Memory Disorders; Memory, Short-Term; Neuropsychological Tests; Parents; Quetiapine Fumarate; Risperidone; Schizophrenia; Severity of Illness Index; Young Adult

Episodic memory is the capacity to recall an event in time and place (What? Where? When?). Impaired episodic memory is a debilitating cognitive symptom in schizophrenia but is poorly controlled by currently available antipsychotic drugs. Consistent with glutamatergic abnormality in schizophrenia, the NDMA receptor antagonist, phencyclidine (PCP), induces persistent 'schizophrenia-like' symptoms including memory deficits in humans and rodents and is widely used as an animal model of the disorder. However, in contrast to humans, PCP and PCP withdrawal-induced memory deficits in rodents are reversed by antipsychotic drugs such as clozapine. One possible explanation is that the memory tasks used in animal studies do not simultaneously test the What? Where? When? components that characterize episodic memory in human tasks. We investigated whether subchronic PCP withdrawal disrupts memory in rats in a task that requires simultaneous integration of memory for object, place and context. Rats learn to discriminate objects under specific spatial and contextual conditions analogous to the What? Where? When? components of human episodic memory. We found that PCP withdrawal impaired performance on this task and that the atypical antipsychotic drug clozapine did not reverse this impairment. However the acetylcholinesterase inhibitor (AChEI) donepezil, which has been shown to improve episodic memory in humans did reverse the effect of PCP. This suggests that PCP withdrawal disruption of object-place-context recognition in rats may prove to be a useful model to investigate episodic memory impairment in schizophrenia and supports the suggestion that AChEIs could prove to be a useful pharmacological strategy to specifically treat episodic memory problems in schizophrenia.

Topics: Animals; Clozapine; Donepezil; Indans; Male; Memory Disorders; Memory, Episodic; Phencyclidine; Piperidines; Rats; Substance Withdrawal Syndrome

Abnormal function of NMDA receptors is believed to be a contributing factor to the pathophysiology of schizophrenia. NMDAR subunits and postsynaptic-interacting proteins of these channels are abnormally expressed in some patients with this illness. In mice, reduced NMDAR expression leads to behaviors analogous to symptoms of schizophrenia, but reports of animals with mutations in core postsynaptic density proteins having similar a phenotype have yet to be reported. Here we show that reduced expression of the neuronal RasGAP and NMDAR-associated protein, SynGAP, results in abnormal behaviors strikingly similar to that reported in mice with reduced NMDAR function. SynGAP mutant mice exhibited nonhabituating and persistent hyperactivity that was ameliorated by the antipsychotic clozapine. An NMDAR antagonist, MK-801, induced hyperactivity in normal mice but SynGAP mutants were less responsive, suggesting that NMDAR hypofunction contributes to this behavioral abnormality. SynGAP mutants exhibited enhanced startle reactivity and impaired sensory-motor gating. These mice also displayed a complete lack of social memory and a propensity toward social isolation. Finally, SynGAP mutants had deficits in cued fear conditioning and working memory, indicating abnormal function of circuits that control emotion and choice. Our results demonstrate that SynGAP mutant mice have gross neurological deficits similar to other mouse models of schizophrenia. Because SynGAP interacts with NMDARs, and the signaling activity of this protein is regulated by these channels, our data in dicate that SynGAP lies downstream of NMDARs and is a required intermediate for normal neural circuit function and behavior. Taken together, these data support the idea that schizophrenia may arise from abnormal signaling pathways that are mediated by NMDA receptors.

Topics: Acoustic Stimulation; Analysis of Variance; Animals; Antipsychotic Agents; Behavior, Animal; Behavioral Symptoms; Clozapine; Cross-Over Studies; Disease Models, Animal; Dizocilpine Maleate; Excitatory Amino Acid Antagonists; Exploratory Behavior; Gene Expression Regulation; Inhibition, Psychological; Locomotion; Memory Disorders; Memory, Short-Term; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mutation; Neuropsychological Tests; ras GTPase-Activating Proteins; Reflex, Startle; Schizophrenia; Social Behavior; Stereotyped Behavior

Nicotinic receptor decreases in the frontal cortex and hippocampus are important mediators of cognitive impairment in both schizophrenia and Alzheimer's disease. Drug treatments for these diseases should take into account the impacts of compromised brain function on drug response. This study investigated the impact of compromised nicotinic receptor activity in the frontal cortex in rats on memory function. Since both Alzheimer's disease and schizophrenia can involve psychosis, antipsychotic drugs are often given. The impacts of antipsychotic drugs on cognitive function have been found to be quite variable. It is the hypothesis of this and previous studies that the cognitive effects of antispychotic drugs on cognitive function depend on the integrity of brain systems involved in cognition. Previously in studies of the hippocampus, we found that chronic inhibition of beta2-containing nicotinic receptors with dihydro-beta-erythrodine (DHbetaE) impaired working memory and that this effect was attenuated by the antipsychotic drug clozapine. In contrast, chronic hippocampal alpha7 nicotinic receptor blockade with methyllycaconitine (MLA) potentiated the clozapine-induced memory impairment which is seen in rats without compromised nicotinic receptor activity. The current study determined medial frontal cortical alpha7 and beta2-containing nicotinic receptor involvement in memory and the interactions with antipsychotic drug therapy with clozapine. Chronic DHbetaE and MLA infusion effects and interactions with systemic clozapine were assessed in female rats tested for memory on the radial-arm maze. Antipsychotic drug interactions with chronic systemic nicotine were investigated because nicotinic procognitive treatment has been proposed. The same local infusion DHbetaE dose that impaired memory with hippocampal infusion did not impair memory when infused in the medial frontal cortex. Frontal DHbetaE infusion potentiated clozapine-induced memory impairment, whereas previously the memory impairment caused by hippocampal DHbetaE infusion was attenuated by clozapine. Frontal cortical MLA infusions at a dose that previously was found to potentiate the clozapine-induced memory impairment with hippocampal infusion had no significant effect when infused into the medial frontal cortex. The location and subtype of nicotinic receptor underactivity are critical determinates for clozapine effects on memory. Patients with hippocampal beta2-containing nicotinic receptor loss may

Topics: Aconitine; alpha7 Nicotinic Acetylcholine Receptor; Animals; Antipsychotic Agents; Cerebral Cortex; Chronic Disease; Clozapine; Dihydro-beta-Erythroidine; Female; Maze Learning; Memory Disorders; Memory, Short-Term; Microinjections; Nicotinic Antagonists; Prefrontal Cortex; Rats; Rats, Sprague-Dawley; Receptors, Nicotinic

We report here the case of a 19-year-old man with paranoid schizophrenia who responded only partially to treatment with daily doses of clozapine, 1800 mg; aripiprazole, 20 mg; and clonazepam, 6 mg. We reduced the clozapine to 1600 to 1700 mg, maintaining therapeutic serum levels, and added a course of electroconvulsive therapy that included 24 treatments. Therapeutic results were minimal. However, adverse effects were limited to mild cognitive disturbances. Our experience adds to other reports suggesting that clozapine and electroconvulsive therapy can be combined without causing excessive adverse effects.

Topics: Antipsychotic Agents; Clozapine; Combined Modality Therapy; Confusion; Electroconvulsive Therapy; Humans; Male; Memory Disorders; Psychiatric Status Rating Scales; Schizophrenia, Paranoid; Young Adult

Maintenance electroconvulsive therapy is used for refractory bipolar disorder. We present a middle-aged man with refractory bipolar disorder who was successfully treated with maintenance electroconvulsive therapy and long-acting risperidone.

Topics: Antipsychotic Agents; Clozapine; Combined Modality Therapy; Confusion; Electroconvulsive Therapy; Humans; Male; Memory Disorders; Psychiatric Status Rating Scales; Schizophrenia, Paranoid; Young Adult

Reasoning and problem solving in the spatial domain are important aspects of executive function that are reliably impaired in schizophrenia, and the Groton Maze Learning Test(c) (GMLT) provides a valid measure of spatial working memory. In the current study, 34 patients with first-episode schizophrenia and 20 matched controls were assessed for baseline spatial working memory abilities using this hidden maze learning test. Approximately one month after baseline assessment, allowing for symptoms to stabilize in response to treatment with therapeutic doses of atypical antipsychotic medications for individuals with schizophrenia, all participants were again assessed with the GMLT. Prior to pharmacologic intervention, patients with schizophrenia showed significant impairments in performance of all aspects of the GMLT, including measures of learning efficiency and error monitoring. One month of treatment was associated with a reliable improvement in these domains, although impairments in accuracy and error monitoring on this spatial working memory test persisted despite symptomatic improvement. These results indicate that impairments in spatial working memory are present at the earliest stages of the illness, and that such deficits in performance remain present, albeit ameliorated, after treatment with atypical antipsychotic medication.

Topics: Adult; Antipsychotic Agents; Clozapine; Cognition Disorders; Control Groups; Female; Follow-Up Studies; Hospitalization; Humans; Male; Maze Learning; Memory; Memory Disorders; Memory, Short-Term; Neuropsychological Tests; Problem Solving; Psychometrics; Risperidone; Schizophrenia; Schizophrenic Psychology; Space Perception; Treatment Outcome

Prospective memory (PM) refers to the ability to execute a delayed intention and is different from retrospective memory (RM) in its nature and underlying mechanism (e.g., intention formation, maintenance, detection of PM cue and intention execution). Although preliminary studies have found PM impairment in patients with schizophrenia, the nature and magnitude of this problem in this clinical group is not yet fully known. The current study aimed to further clarify the nature of this impairment in schizophrenia. Fifty-four patients with schizophrenia and fifty-four healthy volunteers matched on demographic variables, IQ and executive functions took part in the study. Time-, event-, and activity-based PM tasks and a set of neurocognitive tests were administered to the participants. Results showed that patients with schizophrenia performed significantly worse on all sub-types of PM tasks, even after controlling for neurocognitive functions such as working memory, verbal memory, visual memory, and executive function. These findings suggest PM deficit is a primary deficit rather than a secondary consequence of neurocognitive impairments in schizophrenia. Analysis found that PM deficits may be mainly due to the impairment of the cue detection and intention retrieval stage.

Topics: Adult; Clozapine; Cognition Disorders; Control Groups; Cues; Female; Form Perception; Humans; Intention; Judgment; Male; Memory Disorders; Memory, Short-Term; Mental Recall; Models, Psychological; Neuropsychological Tests; Psychomotor Performance; Schizophrenia; Schizophrenic Psychology; Semantics

Cognitive deficits are a core feature of patients with schizophrenia and methamphetamine (METH) psychosis. We have recently found that repeated METH treatment (1 mg/kg, s.c.) in mice, which induces behavioral sensitization, impairs long-term recognition memory in a novel object recognition test (NORT) and that the impairment is ameliorated by clozapine, but not haloperidol. Recent studies indicate that minocycline, a second-generation tetracycline, has potent neuroprotective effects in various animal models of neurological diseases.. In the present study, we investigated the effect of minocycline on learning and memory in the NORT and behavioral sensitization in mice that had been administered METH for 7 days.. When minocycline (20-40 mg/kg) was administered intraperitoneally once a day for seven consecutive days to mice that had previously been treated with METH for 7 days, it ameliorated the METH-induced impairment of recognition memory in a dose-dependent manner, although the same treatment with minocycline had no effect on behavioral sensitization to METH. The administration of minocycline, together with METH, inhibited the development of METH-induced behavioral sensitization. The improvement in memory caused by minocycline was associated with an amelioration of the novelty-induced activation of extracellular signal-regulated kinase 1/2 in the prefrontal cortex of METH-treated mice.. These results suggest that minocycline is useful for the treatment of cognitive deficits in patients with METH psychosis or schizophrenia.

Topics: Animals; Behavior, Animal; Clozapine; Dose-Response Relationship, Drug; Exploratory Behavior; Haloperidol; Injections, Intraperitoneal; Injections, Subcutaneous; Male; Memory Disorders; Methamphetamine; Mice; Mice, Inbred ICR; Minocycline; Mitogen-Activated Protein Kinase 3; Motor Activity; Neuroprotective Agents; Phosphorylation; Time Factors

Although chronic use of methamphetamine (METH) leads to long-lasting cognitive dysfunction in humans, there are few reports about an animal model that reflects METH-induced impairment of working memory.. In this study, we investigated the effect of repeated METH treatment on spatial working memory in rats.. Rats were repeatedly administered METH (2 mg/kg) once a day for 7 days, and their memory function was assessed with a delayed spatial win-shift task in a radial arm maze. The task consisted of two phases, a training phase and a test phase, separated by a delay.. METH-treated animals showed an impairment of performance in the test phase when the delay time was increased from 5 to 30 min or longer. The effect of METH persisted for at least 14 days after the drug withdrawal. METH-induced impairment of working memory was reversed by clozapine (3 and 10 mg/kg, for 7 days), but not haloperidol (1 and 2 mg/kg, for 7 days). The improving effect of clozapine diminished 7 days after the withdrawal. Phosphorylated extracellular signal-regulated kinase1/2 (ERK1/2) levels were significantly increased in the hippocampus of saline-treated control rats from 5 to 60 min after the training phase. In contrast, hyperphosphorylation of ERK1/2 was abolished in the hippocampus of rats treated with METH.. These findings suggest that repeated METH treatment induces impairment of working memory, which is associated with a dysfunctional ERK1/2 pathway in the hippocampus. Furthermore, clozapine may be effective for the treatment of METH-induced cognitive dysfunction.

Topics: Administration, Oral; Animals; Antipsychotic Agents; Blotting, Western; Central Nervous System Stimulants; Clozapine; Dose-Response Relationship, Drug; Drug Administration Schedule; Haloperidol; Hippocampus; Injections, Subcutaneous; Male; Maze Learning; Memory Disorders; Methamphetamine; Mitogen-Activated Protein Kinase 3; Phosphorylation; Rats; Rats, Wistar; Time Factors

Cognitive dysfunction is increasingly considered to be the strongest clinical predictor of poor long-term outcome in schizophrenia. Associations have been found between the severity of cognitive deficits and social dysfunction, impairments in independent living, occupational limitations, and disturbances in quality of life (QOL).. In this cross-sectional study, the relationships of cognitive deficits and treatment outcomes in terms of QOL, needs, and psychosocial functioning were examined in 60 outpatients with schizophrenia who had a duration of illness over 2 years and had been treated with either clozapine or olanzapine for at least 6 months.. The present study suggests that cognitive functioning might be a predictor of work functioning/independent living outcome in stabilized patients with schizophrenia: deficits of visual memory and working memory were negatively associated with occupational functioning, and older patients lived independently and/or in a stable partnership more often. The patients' assessments of QOL and needs for care did not show any significant associations with cognitive functioning.. These findings suggest that cognitive functioning is a key determinant of work functioning/independent living for stable outpatients with schizophrenia.

Topics: Adult; Age Factors; Antipsychotic Agents; Benzodiazepines; Clozapine; Cognition; Cognition Disorders; Comorbidity; Cross-Sectional Studies; Female; Humans; Male; Memory Disorders; Neuropsychological Tests; Olanzapine; Outpatients; Predictive Value of Tests; Quality of Life; Schizophrenia; Schizophrenic Psychology; Treatment Outcome