Risperidone in the Treatment of Patients with Chronic Schizophrenia: a Multi-National, Multi-Centre, Double-Blind, Parallel-Group Study versus Haloperidol

BackgroundThis study was performed in order to evaluate the short-term efficacy and safety of fixed risperidone doses compared to haloperidol.MethodIn a multi-national, parallel-group, double-blind study, patients with chronic schizophrenia (DSM–III–R) were randomly assigned to risperidone 1, 4, 8, 12 or 16 mg or haloperidol 10 mg daily for 8 weeks. Efficacy was assessed by the Positive and Negative Syndrome Scale for schizophrenia (PANSS) and clinical global impression (CGI), and safety primarily by the Extrapyramidal Symptom Rating Scale (ESRS).ResultsOne thousand three hundred and sixty-two patients were evaluated. The optimum risperidone doses were 4 mg and 8 mg, with response rates of 63.4% (56.8%; 69.7%) and 65.8% (59.2%; 71.9%) respectively. Response rate in haloperidol-treated patients was 58.7% (52.0%; 65.3%); the 95% confidence intervals (CI) of the differences between risperidone 4 mg or 8 mg and haloperidol were (–4.3%; 13.7%) and (–1.9%; 16.0%) respectively. There were no significant differences in CGI scores at endpoint between risperidone 4 mg, 8 mg, 12 mg and 16 mg and haloperidol (3.0, 3.0, 3.2, 3.1 and 3.1 respectively); the 95% CI of the differences between risperidone 4 mg or 8 mg and haloperidol were (–0.4; 0.1) and (–0.3; 0.2) respectively. Mean shifts to the maximum total ESRS scores versus baseline (mean (confidence interval)) were significantly greater in haloperidol-treated patients (5.1 (4.0; 6.2)) than in the risperidone 1, 4, 8 and 12 mg groups (1.1 (0.3; 1.9); 1.8 (0.9; 2.7); 2.7 (1.8; 3.6) and 3.2 (2.3; 4.1) respectively (P< 0.05)).ConclusionRisperidone is an effective antipsychotic for the treatment of chronic schizophrenia; doses of 4 and 8 mg seem to be optimal and have a lower incidence of side-effects than haloperidol.