Gender differences in the response to antipsychotic medication in patients with schizophrenia: An individual patient data meta-analysis of placebo-controlled studies

Objective: To determine whether gender and menopausal status moderate the response to antipsychotic medication in patients with schizophrenia. Methods: We analyzed data of 22 short-term placebo-controlled registration trials of antipsychotic medications, which included 5,231 patients with schizophrenia. We applied two-step individual patient data meta-regression analyses to establish the influence of gender and menopausal status on treatment response in mean difference in symptom severity and difference in response (>30% symptom reduction). Analyses were performed both with and without correction for baseline (negative) symptom severity. Results: Antipsychotic treatment is associated with larger mean symptom reduction in women than in men with schizophrenia. The number needed to treat (NNT) for a response in women was 6.9, in men 9.4. Although, we found an age by gender effect, the gender by treatment effect was independent of premenopausal status and baseline (negative) symptom severity. Conclusion: In the treatment of schizophrenia we found evidence of a higher response to antipsychotic medication in women relative to men. We found no evidence that this effect was driven by menopausal status, or baseline (negative) symptom severity. Despite the impact of gender and age on effect size in acute antipsychotic treatment, efficacy was clinically relevant in all subgroups.