A double-blind study of combination of clozapine with risperidone in patients with schizophrenia: effects on cognition. Effectiveness of clozapine versus olanzapine, quetiapine, and risperidone in patients with chronic schizophrenia who did not respond to prior atypical antipsychotic treatment. A double-blind comparative study of clozapine and risperidone in the management of severe chronic schizophrenia. Clozapine and risperidone in chronic schizophrenia: effects on symptoms, parkinsonian side effects, and neuroendocrine response. Efficacy and tolerability of ziprasidone versus risperidone as augmentation in patients partially responsive to clozapine: a randomised controlled clinical trial. Improvement of cognitive function in schizophrenic patients receiving clozapine or zotepine: results from a double-blind study. Different side effect profiles of risperidone and clozapine in 20 outpatients with schizophrenia or schizoaffective disorder: a pilot study. Risperidone versus clozapine in treatment-resistant schizophrenia: a randomized pilot study. Why olanzapine beats risperidone, risperidone beats quetiapine, and quetiapine beats olanzapine: an exploratory analysis of head-to-head comparison studies of second-generation antipsychotics. Risperidone versus clozapine in the treatment of schizophrenic patients with acute symptoms: a double blind, randomized trial. Clozapine v. conventional antipsychotic drugs for treatment-resistant schizophrenia: a re-examination. Clozapine, olanzapine, risperidone, and haloperidol in the treatment of patients with chronic schizophrenia and schizoaffective disorder. Childhood-onset schizophrenia: A double-blind, randomized clozapine-olanzapine comparison. Clozapine versus placebo in Huntington's disease: a double blind randomised comparative study. Some methodological considerations for the clinical evaluation of neuroleptics--comparative effects of clozapine and haloperidol on schizophrenics. The impact upon extra-pyramidal side effects, clinical symptoms and quality of life of a switch from conventional to atypical antipsychotics (risperidone or olanzapine) in elderly patients with schizophrenia.
Atypical antipsychotic drugs produce improvement in some domains of cognition as well as psychopathology in patients with schizophrenia. However, the effect of combinations of atypical antipsychotic drugs on cognitive function is unknown. The aim of this study was to compare the effect of risperidone or placebo on cognitive function in patients with schizophrenia who were previously treated with clozapine monotherapy.
                This prospective, randomized, double-blind, placebo-controlled, 6-week study included 30 patients with DSM-IV schizophrenia. Patients whose psychopathology was no more than partially responsive to clozapine treatment were randomly assigned to receive adjunctive treatment with risperidone (N = 16) up to 6 mg/day or placebo (N = 14). Cognitive test scores for verbal learning and memory, verbal fluency, attention, executive function, verbal working memory, and motor function were the primary outcome measures. Secondary outcome measures included assessment of psychopathology, extrapyramidal side effects, and global functioning. Data were collected between November 2001 and July 2003.
                Significant improvement was found in both treatment groups in a variety of cognitive measures, but there was significantly greater improvement in the placebo-augmented group on measures of initial learning acquisition and attention. The improvement in cognition was not correlated with improvement in psychopathology. There were significant correlations between improvement in verbal working memory, verbal learning and memory, and attention and quality of life and global functioning in the placebo-augmented but not the risperidone-augmented group.
                Adjunctive treatment with risperidone for 6 weeks in patients with schizophrenia who had received chronic treatment with clozapine does not significantly improve cognitive function. When a schizophrenia patient has an inadequate response to treatment with an antipsychotic drug, it is unclear what other antipsychotic to switch to and when to use clozapine. In this study, the authors compared switching to clozapine with switching to another atypical antipsychotic in patients who had discontinued treatment with a newer atypical antipsychotic in the context of the Clinical Antipsychotic Trials for Interventions Effectiveness (CATIE) investigation.
                Ninety-nine patients who discontinued treatment with olanzapine, quetiapine, risperidone, or ziprasidone in phase 1 or 1B of the trials, primarily because of inadequate efficacy, were randomly assigned to open-label treatment with clozapine (N=49) or blinded treatment with another newer atypical antipsychotic not previously received in the trial (olanzapine [N=19], quetiapine [N=15], or risperidone [N=16]).
                Time until treatment discontinuation for any reason was significantly longer for clozapine (median=10.5 months) than for quetiapine (median=3.3), or risperidone (median=2.8), but not for olanzapine (median=2.7). Time to discontinuation because of inadequate therapeutic effect was significantly longer for clozapine than for olanzapine, quetiapine, or risperidone. At 3-month assessments, Positive and Negative Syndrome Scale total scores had decreased more in patients treated with clozapine than in patients treated with quetiapine or risperidone but not olanzapine. One patient treated with clozapine developed agranulocytosis, and another developed eosinophilia; both required treatment discontinuation.
                For these patients with schizophrenia who prospectively failed to improve with an atypical antipsychotic, clozapine was more effective than switching to another newer atypical antipsychotic. Safety monitoring is necessary to detect and manage clozapine's serious side effects. This prospective, double-blind, multicenter, parallel-group study compared the efficacy and safety of therapeutic doses of clozapine and risperidone in patients with severe chronic schizophrenia and poor previous treatment response.
                Male or female patients aged 18-65 years who met DSM-IV criteria for schizophrenia and study requirements for poor previous treatment response (N=273) were randomly assigned to double-blind treatment with either clozapine or risperidone administered over 12 weeks in increasing increments. The primary efficacy measures were the magnitude of improvement in Brief Psychiatric Rating Scale (BPRS) and Clinical Global Impression (CGI) scores. Adverse events were recorded throughout the study.
                The magnitude of improvement in mean BPRS and CGI scores from baseline to end of the study was significantly greater in the clozapine group than in the risperidone group. Statistically significant differences in favor of clozapine were also seen for most of the secondary efficacy measures (Positive and Negative Syndrome Scale, Calgary Depression Scale, Psychotic Depression Scale, and Psychotic Anxiety Scale). The adverse event profile was similar for both treatment groups, with a lower risk of extrapyramidal symptoms in the clozapine group.
                Clozapine showed superior efficacy over risperidone in this patient population. Both treatments were equally well tolerated as demonstrated through their adverse event profiles, although as expected clozapine was associated with a lower risk of extrapyramidal symptoms than risperidone. Clozapine and risperidone were the first two "second-generation" antipsychotic drugs approved for schizophrenia. There is currently little information about their comparative efficacy from head-to-head clinical trials. The purpose of this study was to examine the comparative efficacy of clozapine and risperidone for positive and negative symptoms, depression, parkinsonian side effects, and indexes of neuroendocrine function in schizophrenic patients who met a priori criteria for partial response to traditional neuroleptic agents.
                After a baseline fluphenazine treatment period, 29 patients participated in a 6-week, double-blind, parallel-group comparison of the effects of these agents.
                Clozapine was superior to risperidone for positive symptoms and parkinsonian side effects, but there were no significant differences between the drugs on two measures of negative symptoms, Brief Psychiatric Rating Scale total scores, and depression scores. The clozapine patients, but not the risperidone patients, demonstrated significant reductions from the fluphenazine baseline in positive symptoms, total symptoms, and depression. In addition, clozapine produced fewer effects on plasma prolactin than risperidone or fluphenazine. The mean daily doses during week 6 of the trial were 403.6 mg of clozapine and 5.9 mg of risperidone.
                The findings from this study indicate that these drugs have both important differences and similarities in their comparative efficacy in chronically ill, partially responsive patients with schizophrenia. Further research on second-generation antipsychotic drugs in this patient population that addresses key methodological issues, such as optimal dose and treatment duration, are needed. Patients suffering from schizophrenic psychoses sometimes insufficiently respond to antipsychotic monotherapy and then combination approaches are preferred. We aimed in validating the add-on of ziprasidone and risperidone to clozapine, and we performed a randomised head-to-head trial. Patients with partial response to clozapine were randomly attributed to augmentation with ziprasidone (n = 12) or risperidone (n = 12). Efficacy assessments included the Positive and Negative Syndrome Scale (PANSS), the Scale for the Assessment of Negative Symptoms (SANS), the Hamilton Depression Scale (HAMD), the Clinical Global Impression (CGI) and the Global Assessment of Functioning (GAF). Furthermore, several safety and tolerability measures were obtained. After six weeks, both groups showed significant reductions of positive and negative symptoms. In addition, affective state, psychosocial functioning and clozapine side effects improved without significant differences between the groups. Both approaches were well tolerated. However, the ziprasidone group experienced a small elongation of the QTc interval and a reduction of extrapyramidal symptoms. Patients under clozapine-risperidone therapy developed a rise of serum prolactin levels. The clozapine augmentation with ziprasidone or risperidone resulted in significant psychopathological improvements. The side effects differed between the treatment groups. Further head-to-head comparisons of atypical antipsychotics as add-on to clozapine are necessary. Clinical interest in the so-called atypical antipsychotics currently focuses on the possibility of improving the negative symptoms of schizophrenia and the cognitive dysfunction associated with the disease. While clozapine has been shown to be effective in this respect, no data are available on zotepine. We report on a double-blind randomized study designed to evaluate the impact of zotepine and clozapine on cognitive dysfunction in schizophrenia. Cognitive function was operationalized by a maze test in which patients traversed computer-displayed mazes of increasing complexity. Passage time, route, and motor errors were evaluated. 25 schizophrenic (DSM-IIIR) patients were included in each group. After washout, they were randomized on zotepine or clozapine and given up to 450 mg of substance each. Patients were followed for six weeks and evaluated weekly. We report on a subsample of 26 patients matched for baseline BPRS, SANS, and age. 13 matched healthy persons were recruited as controls. ANOVA with group and course over time as factors was used for analysis. Both clozapine and zotepine achieved a highly significant decrease in overall symptoms (BPRS) and negative symptoms (SANS). Zotepine and clozapine were equally effective. In the maze tests, motor errors in simple mazes were stable over time and differentiated schizophrenics from controls as a "trait" marker. In passage time and maze route, schizophrenics performed worse than controls. An improvement by medication was evident in both medication groups, but was more pronounced in the zotepine-treated group. The study confirms previous results on the efficacy of clozapine and zotepine in treating negative symptoms of schizophrenia. The data presented show for the first time that zotepine is efficacious in improving cognitive dysfunction, confirming this substance's value as an atypical antipsychotic. The purpose of this study was to compare the side effect +profiles of clozapine and risperidone.
                The subjects were 20 outpatients with schizophrenia or schizoaffective disorder who were clinically stable on a regimen of clozapine at the time of screening. They underwent a randomized-order crossover comparison of 6 weeks of risperidone treatment and 6 weeks of clozapine treatment. Clinical and neurocognitive variables were assessed by raters blind to medication status, and severity of side effects was determined from patients' self-reports.
                Side effect measures, but not clinical ratings, were significantly different after 6 weeks of treatment with the two drugs. Patients required more benztropine for motor effects and complained of more insomnia with risperidone and more sedation with clozapine. Body weight was higher at the end of clozapine treatment than at the end of risperidone treatment.
                In this exploratory study, the side effect profiles of clozapine and risperidone were consistent with the different pharmacodynamic profiles of the two drugs. 1. The atypical antipsychotic risperidone may constitute an alternative to clozapine, the current treatment of choice for refractory schizophrenia. The objectives of this study were to evaluate the effectiveness of risperidone in comparison to clozapine in everyday practice and to assess the feasibility of a pragmatic trial procedure. 2. Patients were randomly assigned to open-label clozapine or risperidone treatment for 10 weeks and treatment outcomes were assessed blindly. Twenty-one patients were recruited and nineteen entered the randomized phase. 3. Five of 10 participants allocated to clozapine and one of nine risperidone participants dropped out before study completion. Five clozapine patients and six risperidone patients achieved clinical improvement, defined as a 20% decrease in the Positive and Negative Symptom Scale (PANSS) total score. No significant differences between the groups were detected in baseline or endpoint positive or negative symptoms, disease severity, or global or social functioning scores. Patients' opinion on the drugs did not differ between groups. 4. The findings of the intention-to-treat analysis of this study corroborates previous findings that risperidone may be equally effective as clozapine, and supports the feasibility and need of a multicenter randomized pragmatic trial with sufficient power to detect differences between treatments. In many parts of the world, second-generation antipsychotics have largely replaced typical antipsychotics as the treatment of choice for schizophrenia. Consequently, trials comparing two drugs of this class--so-called head-to-head studies--are gaining in relevance. The authors reviewed results of head-to-head studies of second-generation antipsychotics funded by pharmaceutical companies to determine if a relationship existed between the sponsor of the trial and the drug favored in the study's overall outcome.
                The authors identified head-to-head comparison studies of second-generation antipsychotics through a MEDLINE search for the period from 1966 to September 2003 and identified additional head-to-head studies from selected conference proceedings for the period from 1999 to February 2004. The abstracts of all studies fully or partly funded by pharmaceutical companies were modified to mask the names and doses of the drugs used in the trial, and two physicians blinded to the study sponsor reviewed the abstracts and independently rated which drug was favored by the overall outcome measures. Two authors who were not blinded to the study sponsor reviewed the entire report of each study for sources of bias that could have affected the results in favor of the sponsor's drug.
                Of the 42 reports identified by the authors, 33 were sponsored by a pharmaceutical company. In 90.0% of the studies, the reported overall outcome was in favor of the sponsor's drug. This pattern resulted in contradictory conclusions across studies when the findings of studies of the same drugs but with different sponsors were compared. Potential sources of bias occurred in the areas of doses and dose escalation, study entry criteria and study populations, statistics and methods, and reporting of results and wording of findings.
                Some sources of bias may limit the validity of head-to-head comparison studies of second-generation antipsychotics. Because most of the sources of bias identified in this review were subtle rather than compelling, the clinical usefulness of future trials may benefit from minor modifications to help avoid bias. The authors make a number of concrete suggestions for ways in which potential sources of bias can be addressed by study initiators, peer reviewers of studies under consideration for publication, and readers of published studies. 1. In order to verify the hypothesis that risperidone is a useful therapeutic alternative to clozapine the authors carried out a randomized double blind trial in 59 patients with paranoid hallucinatory psychoses. 2. In a treatment lasting 28 days three groups of patients received either 4 mg risperidone (N = 20), 8 mg risperidone (N = 19), or 400 mg clozapine (N = 20) daily. 3. The tolerance of 4 mg risperidone was globally assessed as being better than that of 400 mg clozapine. Drop-outs under clozapine were mostly caused by side effects, whereas under risperidone they tended to occur for therapeutic inefficacy. 4. The antipsychotic effect was highly significant and clinically relevant under both risperidone and clozapine. Although there is a consensus that clozapine is more effective than conventional antipsychotic drugs for treatment-resistant schizophrenia, there is great heterogeneity among results of relevant trials.
                To re-evaluate the evidence comparing clozapine with conventional antipsychotics and to investigate sources of heterogeneity.
                Individual studies were inspected with assessment of clinical relevance of results. Meta-regression analysis was performed to investigate sources of heterogeneity.
                Ten trials were examined. Recent large-scale studies have not found a substantial advantage for clozapine, especially in terms of a clinically relevant effect. Meta-regression showed that shorter study duration, financial support from a drug company and higher baseline symptom score consistently predicted greater advantage of clozapine.
                It may be inappropriate to combine studies in meta-analysis, given the degree of heterogeneity between their findings. The benefits of clozapine compared with conventional treatment may not be substantial. The authors compared the efficacy and safety of three atypical antipsychotics (clozapine, olanzapine, and risperidone) with one another and with haloperidol in the treatment of patients with chronic schizophrenia or schizoaffective disorder.
                In a double-blind trial, 157 inpatients with a history of suboptimal treatment response were randomly assigned to treatment with clozapine, olanzapine, risperidone, or haloperidol for 14 weeks (an 8-week escalation and fixed-dose period followed by a 6-week variable-dose period).
                Clozapine, risperidone, and olanzapine (but not haloperidol) resulted in statistically significant improvements in total score on the Positive and Negative Syndrome Scale. Improvements seen in total and negative symptom scores with clozapine and olanzapine were superior to haloperidol. The atypical drugs, particularly olanzapine and clozapine, were associated with weight gain.
                The effects of atypical antipsychotics in this population were statistically significant but clinically modest. The overall pattern of results suggests that clozapine and olanzapine have similar general antipsychotic efficacy and that risperidone may be somewhat less effective. Clozapine was the most effective treatment for negative symptoms. However, the differences among treatments were small. Childhood-onset schizophrenia is a rare but severe form of the disorder that is frequently treatment resistant. The psychiatrist has a limited evidence base to guide treatment, particularly as there are no trials in children comparing atypical antipsychotics, the mainstay of current treatment.
                To compare the efficacy and safety of olanzapine and clozapine, hypothesizing that clozapine would be more efficacious.
                Double-blind randomized 8-week controlled trial, with a 2-year open-label follow-up.
                National Institute of Mental Health study, January 1998 to June 2005. Patients underwent reassessment 2 years after discharge.
                Children and adolescents recruited nationally, aged 7 to 16 years, meeting unmodified DSM-IV criteria for schizophrenia, and resistant to treatment with at least 2 antipsychotics.
                After drug washout and a 1- to 3-week antipsychotic-free period, patients were randomized to treatment with clozapine (n = 12) or olanzapine (n = 13).
                The Clinical Global Impression Severity of Symptoms Scale and Schedule for the Assessment of Negative/Positive Symptoms.
                Clozapine was associated with a significant reduction in all outcome measures, whereas olanzapine showed a less consistent profile of clinical improvement. While there were moderate to large differential treatment effects in favor of clozapine, these reached significance only in the alleviation of negative symptoms from an antipsychotic-free baseline (P = .04; effect size, 0.89). Clozapine was associated with more overall adverse events. At 2-year follow-up, 15 patients were receiving clozapine with evidence of sustained clinical improvement, but additional adverse events emerged, including lipid anomalies (n = 6) and seizures (n = 1).
                While not demonstrating definitively the superiority of clozapine compared with olanzapine in treatment-refractory childhood-onset schizophrenia, the study suggests that clozapine has a more favorable profile of clinical response, which is balanced against more associated adverse events. To establish the effect of the atypical neuroleptic clozapine on chorea, voluntary motor performance, and functional disability in patients with Huntington's disease.
                Thirty three patients with Huntington's disease participated in a double blind randomised trial. A maximum of 150 mg/day clozapine or placebo equivalent was given for a period of 31 days. Assessments were performed in the week before and at the last day of the trial. Chorea was scored using the abnormal involuntary movement scale (AIMS), the chorea score of the unified Huntington's disease rating scale (UHDRS), and judgement of video recordings. Voluntary motor performance was assessed using the UHDRS motor scale. Patients and their partners completed a questionnaire regarding functional disability. Twelve patients already used other neuroleptic medication, which was kept unchanged during the trial period. Results of neuroleptic naive and neuroleptic treated patients were analysed separately.
                Clozapine tended to reduce chorea in neuroleptic naive patients only (AIMS); improvement seemed more pronounced in patients receiving higher doses of clozapine. Other measures of chorea (UHDRS chorea score, video ratings) showed no improvement. Clozapine had no beneficial effect on chorea in patients already receiving neuroleptic medication. Voluntary motor performance did not improve with clozapine. Neuroleptic naive patients reported aggravation of functional disability, possibly reflecting the frequent occurrence of side effects. Adverse reactions forced trial termination in six patients and dose reduction in another eight, and consisted mainly of drowsiness, fatigue, anticholinergic symptoms, and walking difficulties.
                Clozapine has little beneficial effect in patients with Huntington's disease, although individual patients may tolerate doses high enough to reduce chorea. Because adverse reactions are often encountered, clozapine should be used with restraint in this patient group. For the purpose of evaluating objectively the characteristics of clinical effects of clozapine and haloperidol, a double-blind comparative trial was conducted on 91 schizophrenic in-patients. The changes of symptoms were assessed by means of several psychiatric and behavioral rating scales. The results were analyzed by means of nonparametric statistical methods. Furthermore, application of multivariate analysis was considered. After 12 weeks of treatment, though no significant difference in general improvement rate was noted between the two groups, a marked different spectrum of clinical effects was observed according to the rating scales. Clozapine is superior in anti-delusional, contact-promoting and sedative anxiolytic effect, while haloperidol is superior in anti-autistic effect. Among the side-effects, extrapyramidal symptoms appeared significatly more severe in the haloperidol group. The frequency of appearance of fever, was significantly greater in the clozapine group than the other. The four dropout cases of the clozapine group were all caused by fever. Through this clinical trial, clinical availability and validity of various statistical analytical methods were reconsidered. Atypical antipsychotics are commonly used in the management of schizophrenia in late life with evidence suggesting they induce lower rates of motor disturbance, but have similar efficacy to conventional antipsychotics. Trials in the elderly have been either retrospective, small, of short duration or of a single-arm design.
                To demonstrate the effects upon motor side-effects, efficacy, safety and quality of life (QOL) of switching elderly patients with schizophrenia from conventional antipsychotics to olanzapine or risperidone.
                Elderly patients with schizophrenia were randomly allocated to olanzapine or risperidone and followed through an open-label crossover period. Between and within group intention to treat analyses were conducted.
                66 patients were randomised (mean age 69.6 [SD +/- 6.2]). Four (11.8%) patients on olanzapine and 8 (26.7%) patients on risperidone failed to complete the crossover because of treatment failure [Odds Ratio (OR) = 2.73[0.73-10.2] p = 0.14]. The mean doses upon completion of switching in each arm were 9.9 mg (SD = 4.2) and 1.7 mg (SD = 1.2) for olanzapine and risperidone respectively. In both arms there was improvement in Parkinsonism, though only olanzapine was associated with a reduction in dyskinetic symptoms. The Brief Psychiatric Rating Scale, Scale for the assessment of Negative Symptoms and Montgomery and Asberg Depression Rating Scale scores all improved through the crossover period in both arms with no between group differences. Treatment with olanzapine was associated with a better response over risperidone on the psychological domain of the World Health Organisation-Quality Of Life [Brief] (WHO-QOL-BREF) scale ( p = 0.02). Patients in the olanzapine arm also demonstrated improvement from baseline in the WHO-QOL-BREF physical, psychological and health satisfaction domains, but risperidone had no effect on any Quality of Life (QOL) measure.
                After switching from a conventional antipsychotic, olanzapine and risperidone were associated with improvement in core symptoms of schizophrenia and motor side effects. Subjects switched to olanzapine were more likely to complete the switching process and show an improvement in psychological QOL.
                Copyright 2003 John Wiley & Sons, Ltd.
Clozapine may be a little more efficacious than zotepine and risperidone but further trials are required to confirm this finding. Clozapine differs more clearly in adverse effects from other second generation antipsychotics and the side-effect profile could be key in the selection of treatment depending on the clinical situation and a patient’s preferences. Data on other important outcomes such as cognitive functioning, quality of life, death or service use are currently largely missing, making further large and well-designed trials necessary. It is also important to take into account that the large number of people leaving the studies early limits the validity and interpretation of our findings.