A comparison of olanzapine versus risperidone for the treatment of schizophrenia: a meta-analysis of randomised clinical trials

Objective. This meta-analysis was carried out to compare the efficacy and safety of olanzapine with risperidone in the treatment of schizophrenia. Methods. Data from randomised, double-blind studies were analysed according to short( less than or equal to12 weeks) and longer-term ( > 12 weeks) treatment, and included all-doses analyses and a sensitivity analysis of clinically relevant doses. A range of efficacy and safety parameters was measured. Results. Olanzapine produced statistically significant improvements in efficacy and safety parameters compared with risperidone over both the short and longer term. Anticholinergic use, study dropouts, changes in Positive and Negative Syndrome Scale and Brief Psychiatric Rating Scale scores, and Quality-of-Life Scale changes, were often significantly in favour of olanzapine. Results from the sensitivity analyses of only clinically relevant doses further favoured olanzapine compared with the all-doses analyses. Conclusion. Small changes in the presence or severity of psychotic symptoms and side-effects can affect a patient's prognosis and quality of life. With this in mind, the efficacy and safety advantages of olanzapine suggested by this study may convey clinical relevance to certain aspects of schizophrenia. However, further research - especially into longer-term efficacy and safety - is needed to confirm the differences between the available antipsychotics.