Clozapine appears to be more effective for severe schizophrenia than other second-generation antipsychotics, but safety concerns remain, a systematic review and meta-analysis suggest.

US researchers searched the literature for non-randomised cohort studies reporting effectiveness and/or safety outcomes when comparing clozapine with other second-generation antipsychotics (SGAs) in schizophrenia or schizoaffective disorder.

They included data from 63 cohort studies involving more than 109,000 patients in the meta-analysis, published in JAMA Psychiatry.

Patients’ mean age was 39, 60% were men, the mean illness duration was 11 years and mean study duration was 19 months.