Comparison of olanzapine and risperidone in 367 first-episode patients with non-affective or affective psychosis: results of an open retrospective medical record study.

INTRODUCTION: Previous studies comparing olanzapine (OLZ) and risperidone (RIS) have tended to focus on multiple-episode patients, with no studies examining their comparative efficacy in a non-selective sample of first-episode psychosis.

METHODS: The Early Psychosis Prevention and Intervention Centre in Australia had admitted 786 first-episode psychosis (FEP) patients between 1998-2000. Data were collected from the medical records (MR) of 367 patients, which met inclusion criteria. The primary objective was to evaluate the efficacy of OLZ vs. RIS as measured by CGI-S, CGI-BP (symptomatic level), GAF and SOFAS (functioning level).

RESULTS: 367 FEP patients were entered into the study, 278 in the RIS- (2.7 mg/day) and 89 in the OLZ group (10.2 mg/day). No between-group differences were found in non-affective FEP (n = 273). In affective FEP patients (n = 94), mainly treated for acute mania (86.7 %), OLZ treatment was related to better response on the symptomatic (CGI-S; p = .002), but not on the functioning level (GAF and SOFAS; ns). There were trends in the OLZ group towards a higher rate of remission of positive symptoms ( p = .054) and a shorter treatment duration to reach this remission in affective FEP patients ( p = .077). More extrapyramidal side effects ( p <.001) were related to RIS and more weight gain to OLZ-treatment ( p <.001).

DISCUSSION: Despite the limitations of a retrospective MR design, study results suggest equal therapeutic efficacy of OLZ and RIS in non-affective FEP and some therapeutic advantages of OLZ compared to RIS in affective FEP patients, especially in those with acute mania. Results may serve as hypotheses for future randomised controlled trials.