Clozapine v. conventional antipsychotic drugs for treatment-resistant schizophrenia: a re-examination.
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.


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


METHODS
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.
Moncrieff
Joanna
J
Department of Psychiatry and Behavioural Science, University College London, UK.
D014150:Antipsychotic Agents / Q000627:therapeutic use*; D003024:Clozapine / Q000627:therapeutic use*; D004345:Drug Industry; D005378:Financial Support; D006801:Humans; D010359:Patient Readmission; D016032:Randomized Controlled Trials as Topic / Q000592:standards; D012559:Schizophrenia / Q000188:drug therapy*; D013997:Time Factors; D017211:Treatment Failure; D016896:Treatment Outcome
D014150:Antipsychotic Agents; D003024:Clozapine