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

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Abstract
Background: This study was performed in order to evaluate the short-term efficacy and safety of fixed risperidone doses compared to haloperidol.Method: In 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).Results: One 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)).Conclusion: Risperidone 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.