Comparing efficacy of first-line atypical antipsychotics: no evidence of differential efficacy between risperidone, olanzapine, quetiapine, ziprasidone, and aripiprazole.

Objective To evaluate the comparative efficacy of the first-line atypical antipsychotics risperidone, olanzapine, quetiapine, ziprasidone, and aripiprazole. Methods We reviewed published short-term, randomised, controlled clinical trials of first-line atypical antipsychotics in the treatment of schizophrenia or schizoaffective disorder that used the Positive and Negative Syndrome Scale to assess efficacy. We used a combined overview analysis to compare the extent of improvement in global symptoms and positive and negative symptoms. We did not analyse adverse event data. Results Although we found considerable variation in the degree of improvement with a particular atypical antipsychotic across different studies, the range and average improvement were similar among all first-line atypicals for all efficacy parameters considered. Dosage was a critical determinant of efficacy, although the most effective dose of each agent varied across studies. There were insufficient data for ziprasidone and aripiprazole to allow their inclusion in the formal overview comparison. Conclusion Despite confounding and methodological limitations, the data we reviewed do not support assertions of differential efficacy between the first-line atypical antipsychotics. Additional controlled comparative studies of the atypical antipsychotics should be of particular interest.