Healthy Skepticism Library item: 1911

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Publication type: Journal Article

Moncrieff J.
Clozapine v. conventional antipsychotic drugs for treatment-resistant schizophrenia: a re-examination
Br J Psychiatry. 2003 Aug; 183:161-6
http://bjp.rcpsych.org/cgi/content/full/183/2/161

Abstract:

BACKGROUND: 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.

AIMS: To re-evaluate the evidence comparing clozapine with conventional antipsychotics and to investigate sources of heterogeneity.

METHOD: Individual studies were inspected with assessment of clinical relevance of results. Meta-regression analysis was performed to investigate sources of heterogeneity.

RESULTS: 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.

CONCLUSIONS: 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.

Keywords:
Antipsychotic Agents/therapeutic use* Clozapine/therapeutic use* Comparative Study Drug Industry Financial Support Humans Patient Readmission Randomized Controlled Trials/standards Schizophrenia/drug therapy* Time Factors Treatment Failure Treatment Outcome