Clozapine, olanzapine, risperidone, and haloperidol in the treatment of patients with chronic schizophrenia and schizoaffective disorder. Positive and negative symptom response to clozapine in schizophrenic patients with and without the deficit syndrome. Clozapine, chlorpromazine, and placebo in newly hospitalized, acutely schizophrenic patients: a controlled, double-blind comparison. Clozapine for the treatment-resistant schizophrenic. A double-blind comparison with chlorpromazine. Clozapine in tardive dyskinesia: observations from human and animal model studies. A double-blind comparative study of clozapine versus chlorpromazine on Chinese patients with treatment-refractory schizophrenia. The risks and benefits of clozapine versus chlorpromazine. [Double-blind clinical study of HF 1854 (LX 100-129, clozapine or leponex) as compared with haloperidol]. The efficacy and safety of clozapine versus chlorpromazine in geriatric schizophrenia. Atypical and conventional antipsychotic drugs in treatment-naive first-episode schizophrenia: a 52-week randomized trial of clozapine vs chlorpromazine. Extrapyramidal reactions and amine metabolites in cerebrospinal fluid during haloperidol and clozapine treatment of schizophrenic patients. Childhood-onset schizophrenia. A double-blind clozapine-haloperidol comparison. Clozapine's effectiveness for patients in state hospitals: results from a randomized trial. A comparison of clozapine and haloperidol in hospitalized patients with refractory schizophrenia. Department of Veterans Affairs Cooperative Study Group on Clozapine in Refractory Schizophrenia. Clozapine in China: a review and preview of US/PRC collaboration. Double-blind comparison of clozapine with chlorpromazine in acute schizophrenic illness. [Multifocal psychopharmaceutic testing ("Multihospital trial")]. Clozapine and haloperidol in a single-blind cross-over trial: therapeutic and biochemical aspects in the treatment of schizophrenia. Clozapine versus chlorpromazine for the treatment of schizophrenia: preliminary results from a double-blind study. Clozapine and haloperidol in moderately refractory schizophrenia: a 6-month randomized and double-blind comparison. Some methodological considerations for the clinical evaluation of neuroleptics--comparative effects of clozapine and haloperidol on schizophrenics.
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. In a preliminary report, the authors observed that clozapine was superior to haloperidol in the treatment of positive and negative symptoms in stable outpatients with schizophrenia. In this final report, they examine the effects of clozapine on positive and negative symptoms in patients with and without the deficit syndrome to determine which patients receive the positive symptom advantage of clozapine and the extent of clozapine's therapeutic effects on negative symptoms. In addition, they examine the long-term effects of clozapine on positive, negative, and affective symptoms, social and occupational functioning, and quality of life.
                Seventy-five outpatients with schizophrenia, who met retrospective and prospective criteria for residual positive or negative symptoms, were entered into a 10-week double-blind, parallel-groups comparison of clozapine and haloperidol. Patients who completed the double-blind study were then entered into a 1-year open-label clozapine study.
                For patients who completed the 10-week double-blind study, clozapine was superior to haloperidol in treating positive symptoms. This effect was not observed in the intent-to-treat analyses. There was no evidence of any superior efficacy or long-term effect of clozapine on primary or secondary negative symptoms. Long-term clozapine treatment was associated with significant improvements in social and occupational functioning but not in overall quality of life.
                For schizophrenic patients who are able to tolerate clozapine therapy, clozapine has superior efficacy for positive symptoms but not negative symptoms and is associated with long-term improvements in social and occupational functioning for patients with and without the deficit syndrome. Clozapine is a unique compound belonging to a relatively new group of antipsychotic agents, the dibenzazepines. To our knowledge, the present study represents the first double-blind, controlled comparison recorded in the United States. The data suggest that clozapine in the present population of newly admitted, acutely psychotic schizophrenic individuals, and in the doses employed, was more effective in overall improvement response, discharge rate, and ameliorating discrete symptoms across the different objective rating scales used than was chlorpromazine (Thorazine) hydrochloride. Placebo was ineffective. Unlike chlorpromazine, no extrapyramidal reactions occurred in those patients ingesting clozapine. Clozapine was also beneficial in reversing abnormal involuntary motor movements. It is an excellent anxiolytic and hypnotic agent. Sedation, hypotension, and hypersalivation are among the more common side effects observed. The treatment of schizophrenic patients who fail to respond to adequate trials of neuroleptics is a major challenge. Clozapine, an atypical antipsychotic drug, has long been of scientific interest, but its clinical development has been delayed because of an associated risk of agranulocytosis. This report describes a multicenter clinical trial to assess clozapine's efficacy in the treatment of patients who are refractory to neuroleptics. DSM-III schizophrenics who had failed to respond to at least three different neuroleptics underwent a prospective, single-blind trial of haloperidol (mean dosage, 61 +/- 14 mg/d) for six weeks. Patients whose condition remained unimproved were then randomly assigned, in a double-blind manner, to clozapine (up to 900 mg/d) or chlorpromazine (up to 1800 mg/d) for six weeks. Two hundred sixty-eight patients were entered in the double-blind comparison. When a priori criteria were used, 30% of the clozapine-treated patients were categorized as responders compared with 4% of chlorpromazine-treated patients. Clozapine produced significantly greater improvement on the Brief Psychiatric Rating Scale, Clinical Global Impression Scale, and Nurses' Observation Scale for Inpatient Evaluation; this improvement included "negative" as well as positive symptom areas. Although no cases of agranulocytosis occurred during this relatively brief study, in our view, the apparently increased comparative risk requires that the use of clozapine be limited to selected treatment-resistant patients. Clozapine has long been considered a useful treatment in patients who have schizophrenia with the neuroleptic-induced delayed-onset side effect tardive dyskinesia. We present data in support of the clinical impression using both an animal model of the disorder and dyskinetic patients themselves. Clozapine produces a lower rate of oral dyskinesia in laboratory rats after 6 months of chronic treatment than does haloperidol (8.6 +/- 1.3 vs. 13.6 +/- 1.4 vacuous chewing movements every 5 minutes, respectively), suggesting a lower propensity to cause tardive dyskinesia. In the human, when clozapine was compared with haloperidol in the treatment of patients with tardive dyskinesia, clozapine produced significantly greater benefit for motor symptoms after 12 months of treatment than did haloperidol (p < .001). Moreover, the dyskinesia rebound, which occurred equally in both drug groups at the beginning of the study, was sustained in the haloperidol group but lost in the clozapine-treated patients. These data suggest that dyskinetic patients lose their symptoms of tardive dyskinesia, along with dopaminergic hypersensitivity, with long-term clozapine treatment. Clozapine has been shown to have superior effectiveness compared with classic neuroleptics in treating refractory schizophrenia in Caucasians, but its efficacy and safety in Chinese have not been adequately studied. Forty Chinese schizophrenic patients were recruited in a 12-week, double-blind, comparative trial. Twenty-one patients were randomly assigned to clozapine treatment and 19 to chlorpromazine treatment. The average dose was 543 +/- 157 and 1163 +/- 228 mg/day for clozapine and chlorpromazine, respectively. The results showed that six clozapine-treated patients (28.6%) had more than 20% improvement in Brief Psychiatric Rating Scale score and were classified as responders, whereas none of the chlorpromazine-treated patients was classified as a responder. The degree of improvement in positive symptoms, negative symptoms and Brief Psychiatric Rating Scale scores in the clozapine group was inversely correlated with the severity of negative symptoms at entry into the trial. Two clozapine-treated patients were withdrawn from the study, one because of leukopenia and nausea, and the other because of vomiting and hypotension. Chlorpromazine treatment was prematurely discontinued in two patients, because of jaundice and over sedation in one, and because of severe weight loss in the other (9 kg). The rate of moderate-to-severe sialorrhea was high in clozapine-treated patients (28.6%). Two clozapine-treated patients and two chlorpromazine-treated patients showed significant improvement in previously existing tardive dyskinesia and one chlorpromazine-treated patient exhibited aggravation of tardive dyskinesia. The results of this study indicate that clozapine treatment might have advantages over chlorpromazine for Chinese schizophrenic patients who are refractory to typical neuroleptic treatment. Clozapine is an atypical antipsychotic drug with reduced risk of unwanted neurological effects in comparison with other drugs. In this multicenter study, 151 hospitalized schizophrenic patients were randomly assigned to treatment under double-blind conditions to assess the antipsychotic efficacy and safety of clozapine versus chlorpromazine. All patients exhibited tardive dyskinesia or other extrapyramidal side effects associated with at least two prior neuroleptics. Eleven patients were dropped from treatment due to extrapyramidal symptoms while being treated with chlorpromazine; only one clozapine patient's treatment was terminated for this reason. Clozapine patients exhibited clinical improvement superior to that of chlorpromazine patients as assessed by the Brief Psychiatric Rating and Clinical Global Impression scales. These results suggest that clozapine is well tolerated and may be therapeutically superior to chlorpromazine in treating psychotic behavior. Agranulocytosis potential can be minimized by frequent white blood cell counts and removing nonresponding patients from treatment prior to the peak risk period (months 2 through 6). nan There has been an absence of controlled studies focusing specifically on neuroleptic treatment in the elderly schizophrenic population. Therefore, we conducted a 12-week double-blind comparison study to assess the efficacy and tolerability of clozapine and chlorpromazine in a group of elderly inpatients with chronic schizophrenia.
                Forty-two elderly DSM-IV schizophrenic veterans were randomly assigned to clozapine or chlorpromazine and assessed for efficacy at baseline and at termination with the Positive and Negative Syndrome Scale (PANSS) and the Clinical Global Impressions scale (CGI). Side effects were also monitored. Medications were titrated, on the basis of clinical response and side effects, to a maximum dose of 300 mg/day of clozapine or 600 mg/day of chlorpromazine.
                The results suggest that both the chlorpromazine and clozapine groups improved their PANSS scores at termination compared with baseline, but the difference between the 2 groups was not statistically significant. The mean CGI scores reflecting severity of illness also demonstrated improvement in both groups over time. Both groups had similar incidences of side effects. One patient in each group had a life-threatening side effect. More patients taking clozapine had tachycardia and weight gain, while more chlorpromazine patients noted sedation.
                We concluded that both clozapine and chlorpromazine are effective treatments for psychosis and behavioral disturbances in geriatric schizophrenia. Both agents had similar incidences of side effects. With careful monitoring and titration of dosage, both clozapine and chlorpromazine were fairly well tolerated in this population. The purported advantages of second-generation or "atypical" antipsychotics relative to first-generation antipsychotics have not been examined in patients with a first episode of schizophrenia. This flexible-dose study examined efficacy and safety in a randomized, double-blind, 52-week trial, comparing chlorpromazine (CPZ) and clozapine (CLZ) in treatment naive patients experiencing their first episode of schizophrenia. In all, 160 inpatients with first-episode schizophrenia or schizophreniform disorder were randomized to CPZ or CLZ and followed them for 52 weeks or until dropout. The primary efficacy measure was time to first remission and proportion of time remaining in remission. The analysis was supplemented by comparisons on a profile of clinical symptoms and side effects. Of these first-episode patients, 80% achieved remission within 1 year (79% CPZ, 81% CLZ). The Kaplan-Meier estimated median time to first remission was 8 weeks for CLZ vs 12 weeks for CPZ (chi(2)(1)=5.56, p=0.02). Both the rate of first achieving remission and the odds for being in remission during the trial were almost doubled for the CLZ group in comparison with the CPZ group. At 12 weeks, CLZ was superior on many rating scale measures of symptom severity while CPZ was not superior on any. These symptom differences remained significant when controlling for EPS differences. By 52 weeks many of the symptom differences between groups were no longer significantly different. Generally, CLZ produced fewer side effects than CPZ, particularly extrapyramidal side effects. There was no significant difference between treatments in weight change or glucose metabolism. For each prior year of untreated psychosis, there was a 15% decrease in the odds of achieving remission (OR=0.85; CI 0.75-0.95). A high proportion of first-episode patients remitted within 1 year. We detected no difference in the proportion of first-episode patients receiving CLZ or CPZ that achieved remission. However, first-episode patients receiving CLZ remitted significantly faster and remained in remission longer than subjects receiving CPZ. While the CLZ group showed significantly less symptomatology on some measures and fewer side effects at 12 weeks, the two treatment groups seemed to converge by 1 year. Longer duration of untreated psychosis was associated with lower odds of achieving remission. 8 male schizophrenic patients participated in a double-blind, cross over study of the extrapyramidal side-effects of haloperidol and clozapine (acute dystonis, Parkinsonism and tardive dyskinesia), together with their effect on homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) in the cerebrospinal fluid (CSF). Haloperidol (9 mg/day) caused Parkinsonism, reduced tardive dyskinesias and increased the HVA concentration in the CSF. Clozapine (225 mg/day) had no effect on the neurological phenomena but reduced HVA and 5-HIAA concentrations in the CSF. During the discontinuation phase following the administration of haloperidol, tardive dyskinesia occurred or was aggravated; this did not occur after administration of clozapine. Accordingly, it is suggested that clozapine does not induce dopaminergic hypersensibility and, therefore, will not induce tardive dyskinesias. Childhood-onset schizophrenia is a rare but severe form of the disorder that is often treatment-refractory. In this study, the efficacy and adverse effects of clozapine and haloperidol were compared for children and adolescents with early-onset schizophrenia.
                Twenty-one patients (mean [+/-SD] age, 14.0 +/- 2.3 years) with onset of Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition-defined schizophrenia that began by age 12 years and who had been nonresponsive to typical neuroleptics participated in the study. Patients were randomized to a 6-week double-blind parallel comparison of clozapine (mean [+/-SD] final dose, 176 +/- 149 mg/d), or haloperidol, (16 +/- 8 mg/d).
                Clozapine was superior to haloperidol on all measures of psychosis (P = .04-.002). Positive and negative symptoms of schizophrenia improved. However, neutropenia and seizures were major concerns. To date, one third of the group has discontinued using clozapine.
                Clozapine has striking superiority for positive and negative symptoms in treatment-refractory childhood-onset schizophrenia. However, due to possibly increased toxic effects in this pediatric population, close monitoring for adverse events is essential. In our study, we examined the effectiveness of clozapine and compared it to the array of medication alternatives typically used in the public sector. Long-term patients in Connecticut's state hospitals who met Food and Drug Administration criteria for clozapine use were invited to participate in this randomized open-label study. Participants (N = 227) were followed for 2 years. Compared with usual care, clozapine was associated with significantly greater reductions in side effects, disruptiveness, and hospitalization, but was not more effective in reducing symptoms or improving quality of life. The groups did not differ in likelihood of being discharged; however, once discharged, clozapine patients were less likely to be readmitted. The results of our study suggest that, compared with the flexible range of medication alternatives available, clozapine is an effective agent. However, at least with this patient population, clozapine did not produce the dramatic improvements is symptomatology or hospital utilization reported in clinical efficacy trials or suggested by mirror-image studies. Clozapine, a relatively expensive antipsychotic drug, is widely used to treat patients with refractory schizophrenia. It has a low incidence of extrapyramidal side effects but may cause agranulocytosis. There have been no long-term assessments of its effect on symptoms, social functioning, and the use and cost of health care.
                We conducted a randomized, one-year, double-blind comparative study of clozapine (in 205 patients) and haloperidol (in 218 patients) at 15 Veterans Affairs medical centers. All participants had refractory schizophrenia and had been hospitalized for the disease for 30 to 364 days in the previous year. All patients received case-management and social-rehabilitation services, as clinically indicated.
                In the clozapine group, 117 patients (57 percent) continued their assigned treatment for the entire year, as compared with 61 (28 percent) of the patients in the haloperidol group (P<0.001). As judged according to the Positive and Negative Syndrome Scale of Schizophrenia, patients in the clozapine group had 5.4 percent lower symptom levels than those in the haloperidol group at all follow-up evaluations (mean score, 79.1 vs. 83.6; P=0.02). The differences on a quality-of-life scale were not significant in the intention-to-treat analysis, but they were significant among patients who did not cross over to the other treatment (P=0.003). Over a one-year period, patients assigned to clozapine had fewer mean days of hospitalization for psychiatric reasons than patients assigned to haloperidol (143.8 vs. 168.1 days, P=0.03) and used more outpatient services (133.6 vs. 97.9 units of service, P=0.03). The total per capita costs to society were high -- $58,151 in the clozapine group and $60,885 in the haloperidol group (P=0.41). The per capita costs of antipsychotic drugs were $3,199 in the clozapine group and $367 in the haloperidol group (P<0.001). Patients assigned to clozapine had less tardive dyskinesia and fewer extrapyramidal side effects. Agranulocytosis developed in three patients in the clozapine group; all recovered fully.
                For patients with refractory schizophrenia and high levels of hospital use, clozapine was somewhat more effective than haloperidol and had fewer side effects and similar overall costs. nan Double Blind comparative trial of a new dibenzodiazepine derivative Clozapine (Leponex) with Chlorpromazine was conducted in the treatment of acute schizophrenic illness over a 6 week period. Factor Analysis of ratings in 9 matched pairs indicates that Clozapine, at 300 mg. per day, is comparable in efficacy to Chlorpromazine in all factors except "Irritability" for which Clozapine appears to be superior. Illness severity and Global Change ratings in all patients showed that Clozapine is more effective in producting a shift towards improvement at the end of 6 weeks. Major side effects reported in Clozapine confirmed sedation and hypersalivation as consistent problems and presence of rigidity and tremor (extra-pyramidal) being at variance with other studies. nan nan Fifteen schizophrenic inpatients were treated in a double-blind comparison study of clozapine versus chlorpromazine. Clozapine appeared to be at least as effective as chlorpromazine without producing any extrapyramidal reactions. Although bone marrow toxicity associated with clozapine has led to the drug's withdrawal from clinical use, data from studies of clozapine demonstrate that a drug can be effective antipsychotic without producing neurologic reactions. Despite the demonstrated efficacy of clozapine in severely refractory schizophrenia, questions remain regarding its efficacy for primary negative symptoms, comparison with a moderate dose of a first-generation antipsychotic, and adverse effects during a longer-term trial. This study examined its efficacy in partially responsive, community-based patients, compared clozapine with moderate-dose haloperidol, and extended treatment to 6 months.
                Randomized, double-blind, 29-week trial comparing clozapine (n = 37) with haloperidol (n = 34). Subjects with schizophrenia who were being treated in community settings at 3 collaborating clinical facilities were enrolled.
                Subjects treated with haloperidol were significantly more likely to discontinue treatment for lack of efficacy (51%) than were those treated with clozapine (12%). A higher proportion of clozapine-treated subjects met an a priori criterion of improvement (57%) compared with haloperidol-treated subjects (25%). Significantly greater improvement was seen in symptoms of psychosis, hostile-suspiciousness, anxiety-depression, thought disturbance, and total score measured on the Brief Psychiatric Rating Scale. No differences were detected in negative symptoms using the Brief Psychiatric Rating Scale or the Schedule for Assessment of Negative Symptoms. Subjects treated with clozapine experienced more excess salivation, dizziness, and sweating and less dry mouth and decreased appetite than those treated with haloperidol.
                Compared with a first-generation antipsychotic given in a moderate dose, clozapine offers substantial clinical benefits to treatment-refractory subjects who can be treated in the community. Advantages are seen in a broad range of symptoms but do not extend to negative symptoms. 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.
Clozapine may be more effective in reducing symptoms of schizophrenia, producing clinically meaningful improvements and postponing relapse, than typical antipsychotic drugs - but data are weak and prone to bias. Participants were more satisfied with clozapine treatment than with typical neuroleptic treatment. The clinical effect of clozapine, however, is, at least in the short-term, not reflected in measures of global functioning such as ability to leave the hospital and maintain an occupation. The short-term benefits of clozapine have to be weighed against the risk of adverse effects. Within the context of trials, the potentially dangerous white blood cell decline seems to be more frequent in children and adolescents and in the elderly than in young adults or people of middle age.
The existing trials have largely neglected to assess the views of participants and their families on clozapine. More community-based long-term randomised trials are needed to evaluate the efficacy of clozapine on global and social functioning as trials in special groups such as people with learning disabilities.