Risperidone treatment of outpatients with schizophrenia: No evidence of sex differences in treatment response

Objective: Given the renewed interest in the role of sex differences in sch izophrenia, we undertook a post hoe analysis to determine whether sex diffe rences in treatment response were present among outpatients with schizophre nia who received risperidone in an 8-week, open-label, Phase IV clinical St udy. Method. We evaluated 330 adult patients (232 men, 98 women) with a DSM-III- R diagnosis of schizophrenia for safety and 292 (206 men, 86 women) for eff icacy. Antipsychotic and antiparkinsonian medications were discontinued at study entry. Treatment with risperidone was initiated at a dosage of 2 mg d aily, increased to the target dosage of 6 mg daily by day 3, and maintained at 6 mg daily until day 14. The dosage was then maintained at 6 mg daily, increased or decreased by 2 mg daily each week, based on the patient's resp onse. Risperidone treatment was given for 8 weeks; the permitted dosage ran ge was 4 mg to 10 mg daily. Results: Both male and female participants responded well to risperidone tr eatment; by the final assessment day, they had experienced decreases from b aseline in their total Positive and Negative Syndrome Scale (PANSS) scores of 41.0% and 36.5%, respectively. Most male (77%) and female (78%) particip ants were considered to be PANSS responders: risperidone was effective agai nst both the positive and negative symptoms of schizophrenia. Both sexes sh owed improvements over baseline in the incidence and severity of parkinsoni sm, dystonia, and dyskinesia. No significant (P > 0.05) sex differences in treatment response were observed for any of the efficacy outcomes or in the incidence and severity of extrapyramidal symptoms (EPS). Conclusions: In this population of outpatients with chronic schizophrenia, both men and women responded well to flexible doses of risperidone. Alo sig nificant sex differences were evident either in treatment response or in ne urological side effects. The absence of sex differences in response to risp eridone treatment may obviate the need for a sex-based differential dosing in schizophrenia management.