RISPERIDONE IN THE TREATMENT OF PATIENTS WITH CHRONIC-SCHIZOPHRENIA -A MULTI-NATIONAL, MULTICENTER, DOUBLE-BLIND, PARALLEL-GROUP STUDY VERSUS HALOPERIDOL

Background. This study was performed in order to evaluate the short-te rm efficacy and safety of fixed risperidone doses compared to haloperi dol. 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 Sca le for schizophrenia (PANSS) and clinical global impression (CGI), and safety primarily by the Extrapyramidal Symptom Rating Scale (ESRS). R esults. One thousand three hundred and sixty-two patients were evaluat ed. The optimum risperidone doses were 4 mg and 8 mg, with response ra tes of 63.4% (56.8%; 69.7%) and 65.8% (59.2%; 71.9%) respectively. Res ponse rate in haloperidol-treated patients was 58.7% (52.0%; 65.3%); t he 95% confidence intervals (CI) of the differences between risperidon e 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 e ndpoint between risperidone 4 mg, 8 mg, 12 mg and 16 mg and haloperido l (3.0, 3.0, 3.2, 3.1 and 3.1 respectively); the 95% CI of the differe nces 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 ESR S scores versus baseline (mean (confidence interval)) were significant ly greater in haloperidol-treated patients (5.1 (4.0; 6.2)) than in th e 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)). Conclusi on. Risperidone is an effective antipsychotic for the treatment of chr onic schizophrenia; doses of 4 and 8 mg seem to be optimal and have a lower incidence of side-effects than haloperidol.