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Review: clozapine shows some improved clinical efficacy over risperidone and zotepine in treatment of schizophrenia, but robust evidence is lacking

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How does clozapine compare with other atypical antipsychotics in the treatment of schizophrenia and schizophrenia-like psychoses?


Mental states assessed by a range of scales (Brief Psychiatric Rating Scale, Positive and Negative Syndrome Scale); adverse reactions; premature study exit; general/global functioning.



Systematic review and meta-analysis.

Data sources

Cochrane Schizophrenia Groups Register (2007), reference lists, individual journals and conference proceedings, pharmaceutical company data.

Study selection and analysis

27 eligible studies were identified involving 3099 participants. Included studies were randomised, single or double blinded trials of clozapine versus other atypical antipsychotics. Eligible comparators were amisulpride, aripiprazole, olanzapine, quetiapine, risperidone, sertindole, ziprasidone and zotepine. Two authors independently selected studies and seven authors independently extracted data.

Main results

Eligible studies were found for five of the eight selected comparators (results summarised in online table). Overall attrition rates were high (30.1%), and data were lacking on outcomes …

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  • Sources of funding Klinikum Rechts der Isar der TU-München, CIGES Capacitacion, Bundesministerium für Bildung und Forschung.


  • Competing interests JPMcE has received speaker honoraria from Lilly, Merck and Sunovion. He has also received research grants from GlaxoSmithKline and Merck and is a consultant for Hoffman LaRoche and Endo. OF has no conflicting interests.