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PubMed2004

Antipsychotic drugs in mania: factors predicting use of antipsychotic medication following inpatient treatment of mania.

Inpatients treated for mania are frequently discharged on antipsychotics. There has been disagreement in clinical guidelines concerning their use, and there is little knowledge of the factors predicting this. The aim of the present study was to identify those factors predicting discharge on typical antipsychotic medication after hospital admission for mania. Data were collected retrospectively from the hospital notes of 74 patients who had 100 consecutive psychiatric hospital admissions for mania during the 1990s. Univariate and multivariate analyses were used to estimate odds ratios. The rate of discharge on typical antipsychotics was 71.6% (53 out of the 74 episodes included in the analyses) (95% confidence interval 61.3-81.9). Three factors were found to predict this with odds ratios significant at the P<0.05 level: (i) use of typical antipsychotics during the first week of admission [odds ratio (OR)=13.3]; (ii) voluntary admission (OR=4.2); and (iii) male gender (OR=8.4). There was no evidence that psychotic symptoms or aggressive behaviour were associated. In conclusion, the use of antipsychotics early in the episode strongly predicted discharge on antipsychotics. It appears that clinicians use antipsychotics for their anti-manic effects and patients are often thought to still need the drugs at the time of discharge.

Adolescent↗

PubMed1993

[A study on the pharmacological properties of atypical antipsychotic drugs: in vivo dopamine and serotonin receptor occupancy by atypical antipsychotic drugs in the rat brain].

In vivo occupancy by typical or atypical antipsychotic drugs of dopamine D-1, D-2 and serotonin (5-HT)2 receptors in the membranes and slices of the rat brain was measured using N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ), an irreversible antagonist at these receptor sites. In the membranes, the occupancy of D-1 receptors in the striatum by all tested drugs except cis-flupenthixol was minimal. Typical antipsychotic drugs such as chlorpromazine (10 mg/kg), haloperidol (1 mg/kg), cis-flupenthixol (1 mg/kg) and zotepine (5 mg/kg) occupied predominantly D-2 receptors in the striatum. Among atypical antipsychotic drugs, sulpiride (30 mg/kg) and amperozide (1 mg/kg) had no effect on the EEDQ-induced reduction in D-1, D-2 or 5-HT2 receptors, whereas clozapine (10 mg/kg), fluperlapine (10 mg/kg), risperidone (1 mg/kg), setoperone (0.25 mg/kg) and ORG 5222 (0.25 mg/kg) occupied mainly 5-HT2 receptors in the frontal cortex. In the slices, the occupancy by all tested drugs of D-1 receptors in the striatum, nucleus accumbens and substantia nigra was minimal with the exception of clozapine which showed about 30% occupancy in the substantia nigra. Typical antipsychotic drugs, chlorpomazine (10 mg/kg) and haloperidol (1 mg/kg) occupied predominantly D-2 receptors in the striatum and the nucleus accumbens. On the other hand, atypical antipsychotic drugs, clozapine (10 mg/kg) and risperidone (1 mg/kg), occupied mainly 5-HT2 receptors in the frontal cortex. These results suggest that there is a certain group of atypical antipsychotic drugs characterized by high occupancy of 5-HT2 receptors and low or minimum occupancy of D-2 receptors. These characteristics may be relevant to their weak potency in producing extrapyramidal side effects in man or catalepsy in rodents. Although we could find no clear regional differences in receptor occupancies by these antipsychotic drugs, further study are needed to elucidate this issue.

Animals↗

PubMed2000

Risperidone versus typical antipsychotic medication for schizophrenia.

BACKGROUND: The 'conventional' neuroleptic drugs, such as haloperidol and chlorpromazine, are frequently used as the first line treatment for people with schizophrenia. However, about 5-25% of these people show poor response to these treatments and side effects often makes compliance with the 'older generation' of drug treatment problematic. Although the efficacy of these medications with respect to 'positive' symptoms is well described, little evidence exists that 'conventional' antipsychotic treatment has any effect on the 'negative' symptoms of schizophrenia. Risperidone is one of the 'new generation' neuroleptic compounds. As well as its reputed tendency to cause fewer movement disorders it is claimed that risperidone may improve negative symptoms. OBJECTIVES: To evaluate the effectiveness of risperidone for schizophrenia in comparison to 'conventional' neuroleptic drugs. SEARCH STRATEGY: Electronic searches of Biological Abstracts (1980-1997), Cochrane Schizophrenia Group's Register (1997), The Cochrane Library (1997, Issue1), EMBASE (1980-1997), MEDLINE (1966-1997), PsycLIT (1974-1997), and SCISEARCH (1997) were undertaken. References of all identified studies were searched for further trial citations. Pharmaceutical companies and authors of trials were contacted. SELECTION CRITERIA: All randomised trials comparing risperidone to any 'conventional' neuroleptic treatment for those with schizophrenia or other serious mental illnesses. DATA COLLECTION AND ANALYSIS: Citations and, where possible, abstracts were independently inspected by reviewers, papers ordered, re-inspected and quality assessed. Data were also independently extracted. Sensitivity analyses on dose of risperidone, haloperidol and duration of illness were undertaken for the primary outcomes of clinical improvement, side effects (movement disorders) and acceptability of treatment. For homogeneous dichotomous data the odds ratio (OR), 95% confidence interval (CI) and, where appropriate, the number needed to treat (NNT) were calculated on an intention-to-treat basis. MAIN RESULTS: Twelve short-term studies and two long term studies provided data on 3401 people. This review provides no evidence relating to the effect of risperidone on cognitive or social functioning, quality of life, employment status, discharge from hospital and relapse rates. Risperidone increases the odds of moderate clinical improvement (OR 0.65, CI 0.55-0.77, NNT 10, CI 7-16). It appears to have little or no additional effect on the positive and negative symptoms of schizophrenia but did have less tendency to cause movement disorders, largely in comparison with haloperidol (OR 0.43, CI 0.34-0.55, NNT 7, CI 5-10) for use of antiparkinsonian medication. Risperidone seems to be more acceptable to those with schizophrenia (OR 0.69 CI 0.57-0.83, NNT 15, CI 10-30, 30% baseline risk of dropping out). Those taking risperidone are also marginally less likely to experience somnolence (OR 0.78, CI 0. 61-0.99, NNT 22). Weight gain, however, is more likely with risperidone (OR 1.51 CI 1.14-2.00, NNT 13). Funnel plots show that smaller studies generally show greater benefit for risperidone than larger studies. A publication bias in favour of risperidone amongst the included studies may explain this effect. Sensitivity analyses on dose of risperidone (excluding those receiving 1 or 2 mg) did not materially change the results for the principal outcomes. Excluding data from those on higher doses of haloperidol (>10mg/day) does marginally change the results. Risperidone is less effective in achieving clinical improvement and preventing dropout but outcomes relating to movement disorders change little. REVIEWER'S CONCLUSIONS: Little can be concluded about the long term effects of risperidone and generalising results beyond a comparison with haloperidol would be imprudent. Risperidone may be more acceptable to those with schizophrenia and have marginal benefits in terms of limited clinical improvement and side

Antipsychotic Agents↗

PubMed2003

Reducing the dose of antipsychotic medications for those who had been treated with high-dose antipsychotic polypharmacy: an open study of dose reduction for chronic schizophrenia.

Antipsychotic medications are often used at higher than the recommended dose and sometimes in a combination regimen to treat schizophrenia. However, in general, high-dose therapies have been abandoned in recent clinical studies. In this study, dose reduction of antipsychotic medication was implemented for patients with chronic schizophrenia, most of whom (81%) had been treated with an antipsychotic high-dose polypharmacy regimen consisting of more than 1000 mg/day in total amount. The results show that merely reducing the amount of antipsychotic led to favourable outcome in 23 out of 41 cases (56%), with another 13 cases (32%) showing no change. Dose reduction ended in failure in only five subjects (12%). Overall, the amount as well as the number of antipsychotic medications was significantly reduced from 1984 mg to 812 mg per day (reductions of 59% and from 3.6 to 2.2, respectively; both P<0.0001). The Global Assessment of Functioning scale improved from 30.6 to 37.2, which reached significance (P<0.001). Accordingly, the Severity of Illness improved from 4.7 to 4.2, and was also significant (P<0.01). Dose reduction is an encouraging strategy to consider for those patients with schizophrenia who have chronically been treated with high-dose antipsychotic polypharmacy, even if judged unavoidable in the past.

Adolescent↗

PubMedDate not supplied

Prescribing conventional antipsychotics in the era of novel antipsychotics: informed consent issues.

The goal of this study was to ascertain why patients are maintained on conventional antipsychotics and whether the risks/benefits and alternative treatments with novel antipsychotics are discussed with these patients. We reviewed the charts of 117 outpatients maintained on conventional antipsychotics at three New York hospitals: Hutchings Psychiatric Center (HPC), Syracuse Veterans Affairs Medical Center (SVA), and the Continuing Day Treatment Program (CDT). The major reasons for maintaining patients on conventional antipsychotics were good response (50%), patient choice (45%), and physician choice (36%). Despite the high incidence of tardive dyskinesia at all three hospitals (range: 12%-50%), physicians often did not discuss the risks/benefits of continuing conventional antipsychotics with the patients. The treating psychiatrist discussed alternative treatments with 37% of patients at SVA, 58% at HPC, and 68% at CDT (P = 0.066, df = 2, Pearson chi(2) test). For patients who are receiving any antipsychotic therapy, discussions about the risks/benefits of treatments are integral for optimal treatment and medicolegal purposes.

Akathisia, Drug-Induced↗

PubMed2000

Novel antipsychotics: issues and controversies. Typicality of atypical antipsychotics.

The typicality of atypical antipsychotic drugs remains debatable. Preclinical studies and findings from randomized, controlled and open trials of clozapine, olanzapine, risperidone, quetiapine, sertindole, ziprasidone and a substituted benzamide were examined. A MEDLINE search was conducted using key words, including "extrapyramidal side effects," "cognition," "schizophrenia" and the generic drug names. Over 140 articles from peer-reviewed journals were reviewed, some of which were based on a meta-analysis. New-generation neuroleptic agents were found to have greater efficacy on the negative symptoms of schizophrenia and to cause fewer unwanted extrapyramidal side effects (EPS) than the traditional antipsychotic drugs. On one hand, atypical neuroleptic agents could be strictly defined as any neuroleptic agent with antipsychotic effects at a dosage that does not cause extrapyramidal side effects. Thus, clozapine is regarded as the "standard" atypical antipsychotic drug. On the other hand, typicality is about dimension rather than category, and we suggest the use of the term "spectrum of atypicality." For example, an emphasis is placed on quetiapine to illustrate where a new compound fits in this spectrum. Although dose-related, atypicality may be more a question of prescription attitude than of a specific characteristic of a compound. The degree to which a new compound is clinically superior to another atypical antipsychotic drug, in terms of improving positive, negative or affective symptoms, cognitive function and long-term outcome, will require further a priori hypotheses based on conceptual frameworks that are clinically meaningful. In addition, the results from industry-sponsored trials should be more comparable to those obtained from investigator-leading trials. Finally, the patient characteristics that define a patient's response to a specific antipsychotic drug are unknown.

Antipsychotic Agents↗

PubMed2005

Antipsychotic and antidepressive effects of second generation antipsychotics: two different pharmacological mechanisms?

Second generation antipsychotics display antidepressive effects in schizophrenic patients that are more pronounced than those of traditional neuroleptics and that go beyond antidepressive effects secondary to the reduction of positive symptoms. The antidepressive potential of second generation antipsychotics is presumably related to their pharmacological mechanisms, which differ from those of traditional neuroleptics. Among others, 5-HT(2A) antagonism is of special relevance for most of the new antipsychotics in this respect. But also special interactions with the dopaminergic system, as is the case with amisulpride and aripiprazole, or noradrenalin- and/or serotonin-reuptake-inhibition, as with ziprasidone and zotepine, should be considered. It can be summarised that the antipsychotic and antidepressive effects of second generation antipsychotics are mostly based on different pharmacological mechanisms. This might be especially true for direct antidepressive effects, i. e. antidepressive effects that are not mediated by the reduction of positive symptoms.

Animals↗

PubMed2006

The orexin-1 receptor antagonist SB-334867 blocks the effects of antipsychotics on the activity of A9 and A10 dopamine neurons: implications for antipsychotic therapy.

Antipsychotic drugs alter the activity of dopamine neurons in the ventral tegmental area (A10) and substantia nigra pars compacta (A9). As there is a dense projection of orexin neurons from the lateral hypothalamus to A10 dopaminergic neurons, and some antipsychotics have been shown to increase the expression of c-fos in orexin-containing cells in the hypothalamus, we hypothesized that stimulation of orexin receptors plays a role in the effects of antipsychotics on the activity of A9 and A10 dopamine cells. Single-unit recordings in anesthetized rats demonstrated the central effects of the selective orexin-1 receptor antagonist SB-334867 (2 mg/kg, intravenous), as it reversed the excitatory effects of orexin-A administration (6 microg, intracerebroventricular) on the activity of locus coeruleus (LC) cells. Recordings from midbrain dopamine neurons showed that acute administration of SB-334867 alone did not alter the number of spontaneously active A9 or A10 cells, but did reverse: (1) the increase in the number of spontaneously active A9 and/or A10 dopamine cells caused by the acute administration of haloperidol (1 mg/kg, subcutaneous) or olanzapine (10 mg/kg, s.c.) and (2) the decrease in the number of spontaneously active A9 and/or A10 dopamine cells caused by the chronic administration of haloperidol (1 mg/kg/day x 21 days, s.c.) or olanzapine (10 mg/kg/day x 21 days, s.c.). However, SB-334867 did not block a different electrophysiological effect of olanzapine, as it did not block the olanzapine-induced activation of LC cells. These results indicate that activation of orexin-1 receptors plays an important role on the effects of antipsychotic drugs on dopamine neuronal activity and may play an important role in the clinical effects of antipsychotic drugs.

Action Potentials↗

PubMed2006

Serum monitoring of antipsychotic drug levels during concomitant administration of sertraline and antipsychotic medication.

OBJECTIVE: To assess whether pharmacokinetic drug interactions occur when sertraline is added to antipsychotic medications. METHOD: Forty-eight patients with remitted DSM-IV schizophrenia and comorbid major depression were randomized to placebo for 6 weeks or sertraline 50 mg for 4 weeks followed by sertraline 50 mg to 100 mg for 2 weeks for nonresponders. Treatment with the patients' usual antipsychotic continued. Weekly clinical outcome assessments occurred for 6 weeks, and serum samples for drug monitoring were collected at Weeks 1, 5, and 6. Serum concentrations of sertraline and antipsychotics were measured with standard assays. RESULTS: In both placebo- and sertraline-treated groups, most patients displayed minor fluctuations in antipsychotic serum levels over 6 weeks. There was no clinical evidence of drug interactions in the sertraline-treated group. CONCLUSIONS: Clinically significant adverse effects did not occur despite variable antipsychotic serum levels with or without sertraline. Concern about pharmacokinetic interactions should not deter the use of sertraline for depression in individuals with schizophrenia.

Adolescent↗

PubMed2001

Antipsychotic-induced extrapyramidal syndromes. Risperidone compared with low- and high-potency conventional antipsychotic drugs.

AIM: To compare the risk of extrapyramidal syndromes (EPS) between patients using risperidone and those using low-potency conventional antipsychotic drugs (APDs) in outpatient clinical practice, as measured by the use of anticholinergic medication. We tried to replicate results from previous clinical trials that compared risperidone with high-potency APDs. METHOD: Data was obtained from the PHARMO database containing filled prescriptions of 450,000 community-dwelling people in The Netherlands from 1986 to 1998. From the patients aged 15-54 years who had been newly treated with APDs, we defined mutually exclusive cohorts according to the APD first prescribed to a patient. APD exposure was followed until the first prescription of anticholinergic medication and was censored when APD prescribing was interrupted or switched. We estimated relative risks between risperidone and commonly used low-potency and high-potency APDs using Cox proportional hazards models, adjusting for age, gender, dose and other potential confounders. RESULTS: In 4094 patients who had been newly prescribed antipsychotic drugs, the overall incidence rate of anticholinergic drug therapy was 556 per 1000 person-years, which was dose dependent. Prescribed doses of all antipsychotics were low. While, in accordance with previous trials, risperidone showed a lower risk of EPS than the high potency APDs such as haloperidol (RR 0.26; 95% CI 0.10-0.64), we did not observe a lower EPS rate than low-potency APDs (risperidone vs thioridazine RR 1.73, 95% CI 0.49-6.13; risperidone vs pipamperone RR 2.50, 95% CI 0.78-8.04). CONCLUSION: The reduced EPS rates observed when comparing risperidone with high-potency antipsychotics such as haloperidol may not apply to comparisons with low-potency drugs.

Adolescent↗

PubMed2005

Antipsychotic-like vs cataleptogenic actions in mice of novel antipsychotics having D2 antagonist and 5-HT1A agonist properties.

A new generation of proven or potential antipsychotics, including aripiprazole, bifeprunox, SSR181507 and SLV313, exhibit agonist actions at serotonin 5-HT1A receptors, but little comparative data are available on their pharmacological profiles. Here, we compared in mice the in vivo antipsychotic-like vs cataleptogenic activities of these compounds with those of drugs that exhibit little interaction at 5-HT1A receptors, such as haloperidol, olanzapine and risperidone. All the drugs dose-dependently reduced apomorphine-induced climbing or sniffing and, with the exception of ziprasidone, produced complete suppression of these responses. In the bar catalepsy test, when administered alone, haloperidol, olanzapine and risperidone produced marked catalepsy, whereas, at doses up to 40 mg/kg, aripiprazole, SLV313, SSR181507, and sarizotan produced little or no catalepsy. The latter compounds, therefore, displayed a large separation between doses with 'antipsychotic-like' and those with cataleptogenic actions. When 5-HT1A receptors were blocked by pretreatment with WAY100635 (2.5 mg/kg, s.c.), cataleptogenic properties of SSR181507 and sarizotan were unmasked, and the catalepsy induced by bifeprunox was enhanced. In the case of aripiprazole and SLV313, although WAY100635 produced upward shifts in their dose-response, the magnitude of catalepsy appeared to reach an asymptotic plateau, suggesting that other mechanisms may be involved in their low cataleptogenic liability. The present data confirm that 5-HT1A receptor activation reduces or even completely prevents the cataleptogenic potential of novel antipsychotic agents. Further, they indicate that the balance of affinity and/or efficacy between D2 and 5-HT1A receptors profoundly influences their pharmacological activities, and will likely impact their therapeutic profiles.

Animals↗

PubMedDate not supplied

[Long-acting antipsychotics in the maintenance treatment of schizophrenia. Part II. Management of medications, integration of the multiprofessional team, and perspectives with the formulation of new a new generation of long-acting antipsychotics].

Among various topics, this second part addresses indication and beginning of treatment, dose inter-individual variability and interval between injections, appointment frequency and special strategies during treatment relapse. Considering that poor adherence to antipsychotic treatment is a major factor in schizophrenic relapse, that the new generation of antipsychotic drugs, despite lower incidence of extrapyramidal side effects and better overall tolerability, did not change this condition in relation to conventional drugs and in view of the superiority of depot antipsychotics in comparison with conventional ones administered orally, the long-acting formulation of new generation antipsychotics can certainly improve the adherence and regularity of the medication regimen and decrease relapse rates in patients with schizophrenia. Furthermore, family participation in treatment is of great importance, as well as the attitude and integration of the medical team in realizing different tasks.

Acute Disease↗

PubMed1988

Antipsychotic-withdrawal akathisia versus antipsychotic-induced akathisia: further evidence for the existence of tardive akathisia.

The authors present a study in which 33 chronic schizophrenic patients who, when withdrawn from antipsychotic drug treatment for more than 2 weeks, presented with concurrent signs of akathisia and tardive dyskinesia; however, signs of akinesia, facial masking, rigidity, or dystonia were not concurrent with the patients' akathetic presentation. In a subsequent study phase, these patients were treated with antipsychotics for up to 6 weeks. The dyskinetic signs that had been dramatically more severe in those patients exhibiting akathisia following withdrawal from antipsychotic medication continued for up to 6 weeks following the renewal of antipsychotic drug therapy. These findings help to confirm a relationship between tardive dyskinesia and a persistent akathisia of later onset known as tardive akathisia.

Adult↗

PubMed2006

Randomized controlled trial of the effect on Quality of Life of second- vs first-generation antipsychotic drugs in schizophrenia: Cost Utility of the Latest Antipsychotic Drugs in Schizophrenia Study (CUtLASS 1).

CONTEXT: Second-generation (atypical) antipsychotics (SGAs) are more expensive than first-generation (typical) antipsychotics (FGAs) but are perceived to be more effective, with fewer adverse effects, and preferable to patients. Most evidence comes from short-term efficacy trials of symptoms. OBJECTIVE: To test the hypothesis that in people with schizophrenia requiring a change in treatment, SGAs other than clozapine are associated with improved quality of life across 1 year compared with FGAs. DESIGN: A noncommercially funded, pragmatic, multisite, randomized controlled trial of antipsychotic drug classes, with blind assessments at 12, 26, and 56 weeks using intention-to-treat analysis. SETTING: Fourteen community psychiatric services in the English National Health Service. PARTICIPANTS: Two hundred twenty-seven people aged 18 to 65 years with DSM-IV schizophrenia and related disorders assessed for medication review because of inadequate response or adverse effects. INTERVENTIONS: Randomized prescription of either FGAs or SGAs (other than clozapine), with the choice of individual drug made by the managing psychiatrist. MAIN OUTCOME MEASURES: Quality of Life Scale scores, symptoms, adverse effects, participant satisfaction, and costs of care. RESULTS: The primary hypothesis of significant improvement in Quality of Life Scale scores during the year after commencement of SGAs vs FGAs was excluded. Participants in the FGA arm showed a trend toward greater improvements in Quality of Life Scale and symptom scores. Participants reported no clear preference for either drug group; costs were similar. CONCLUSIONS: In people with schizophrenia whose medication is changed for clinical reasons, there is no disadvantage across 1 year in terms of quality of life, symptoms, or associated costs of care in using FGAs rather than nonclozapine SGAs. Neither inadequate power nor patterns of drug discontinuation accounted for the result.

Adolescent↗

PubMed1995

Antipsychotic drugs induce Fos protein in the thalamic paraventricular nucleus: a novel locus of antipsychotic drug action.

Monitoring expression of c-fos and other immediate-early genes has proven a useful method for determining potential sites of action of antipsychotic drugs. Most studies of the effects of antipsychotic drugs on immediate-early gene expression have focused on the basal ganglia and allied cortical regions. We now report that clozapine administration markedly increases both the number of cells expressing Fos protein-like immunoreactivity and the amount of Fos protein in the thalamic paraventricular nucleus, but not the contiguous mediodorsal thalamic nucleus. Comparable doses of several dopamine D2-like antagonists, including raclopride, sulpiride, remoxipride and haloperidol, did not induce Fos expression in the paraventricular nucleus. However, loxapine and very high doses of haloperidol resulted in a small but significant increase in paraventricular nucleus Fos expression. The dopamine D1 receptor antagonist SCH23390 did not induce Fos in the paraventricular nucleus or alter the magnitude of the clozapine-elicited increase in Fos expression. The serotonergic 5-hydroxytryptamine2a/2c antagonist ritanserin, alone or in combination with sulpiride, did not increase Fos expression in the paraventricular nucleus. Similarly, the 5-hydroxytryptamine2:D2 antagonist risperidone did not change the amount of Fos protein in the paraventricular nucleus. Neither the alpha 1 adrenergic antagonist prazosin nor the muscarinic cholinergic antagonist scopolamine mimicked the effect of clozapine. The key placement of the paraventricular nucleus as an interface between the reticular formation and forebrain dopamine systems suggests that this thalamic nucleus may be an important part of an extended neural network subserving certain actions of antipsychotic drugs.

Animals↗

PubMed2004

Effects of the classical antipsychotic haloperidol and atypical antipsychotic risperidone on weight gain, the oestrous cycle and uterine weight in female rats.

Antipsychotic drug-induced side effects of weight gain and sexual dysfunction have clinical significance adversely affecting both compliance and morbidity. This study evaluated the effects of haloperidol and the atypical antipsychotic risperidone (0.1-1.0 mg/kg) on weight gain, food and water intake, the oestrous cycle and uterine weight in female hooded Lister rats. Haloperidol and risperidone treated rats displayed marked weight gain, although only risperidone induced significant increases in food consumption over the 21-day period. Neither haloperidol nor risperidone influenced water consumption. Marked disruption of the oestrous cycle was observed in risperidone- and haloperidol-treated animals (0.5 and 1.0 mg/kg), which was supported by significantly reduced uterine weights. The findings presented here suggest that the weight gain and sexual dysfunction induced by antipsychotics may be modelled in rodents. This model may offer insight into the mechanisms involved in mediation of such side effects.

Animals↗

PubMed1999

The effect of long-term antipsychotic treatment on the body weight of patients suffering from chronic schizophrenia: clozapine versus classical antipsychotic agents.

The aim of this study was to evaluate the effect of long-term clozapine treatment on body weight changes in neuroleptic-resistant chronic schizophrenic patients and to compare it with that of classical antipsychotic agents. The body mass index (BMI) of 96 neuroleptic-resistant chronic schizophrenic patients was calculated before the beginning and after long-term (mean +/- SD 1.7 +/- 1.3 years) clozapine treatment. These data were compared to the BMI of 98 chronic schizophrenic patients maintained on classical antipsychotic agents for a similar duration (mean +/- SD 1.9 +/- 1.6 years). A significant elevation in BMI was detected in both groups during these periods (P < 0.0001 versus baseline, for both groups). The change in BMI (delta BMI) was similar in both groups (P < 0.9). We conclude that the increase in body weight caused by long-term (> 6 months) clozapine treatment is comparable to that obtained following long-term classical antipsychotic agents treatment.

Adult↗

PubMed2003

A comparison of drug effects in latent inhibition and the forced swim test differentiates between the typical antipsychotic haloperidol, the atypical antipsychotics clozapine and olanzapine, and the antidepressants imipramine and paroxetine.

Current animal models of antipsychotic activity that have the capacity to dissociate between typical and atypical antipsychotic drugs (APDs) have two drawbacks: they require previous administration of a psychotomimetic drug, and they achieve the dissociation by demonstrating effectiveness of atypical but not typical APDs, thus losing specificity and selectivity for APDs. The present experiments were designed to solve these problems by using two non-pharmacological tests: latent inhibition (LI), in which potentiation of the deleterious effects of non-reinforced stimulus pre-exposure on its subsequent conditioning served as a behavioral index for a common action of typical and atypical APDs (antipsychotic), and the forced swim test (FST), in which reduction of immobility served as a behavioral index for a dissimilar action of these drugs (antidepressant). The typical APD haloperidol (0.1 mg/kg), the atypical APDs clozapine (2.5 mg/kg) and olanzapine (0.6 mg/kg), and the antidepressants imipramine (10 mg/kg) and paroxetine (7.0 mg/kg), produced distinct patterns of action in the two tests: haloperidol potentiated LI and increased immobility in the FST, clozapine and olanzapine potentiated LI and decreased immobility in the FST, and imipramine and paroxetine decreased immobility in the FST and did not potentiate LI. Thus, the comparison of drug effects in LI and FST enabled a discrimination between typical and atypical APDs without losing selectivity for APDs.

Animals↗