International multisite double-blind trial of the atypical antipsychotics risperidone and olanzapine in 175 elderly patients with chronic schizophrenia

Objective: The authors compared the effects of the two most commonly used atypical antipsychotics, risperidone and olanzapine, in elderly patients with schizophrenia. Methods: In an 8-week, international, double-blind study, patients (outpatients, hospital inpatients, and residents of nursing or boarding homes) were randomly assigned to receive risperidone (1 mg to 3 mg/day) or olanzapine (5 mg to 20 mg/day). The main outcome measures were changes in Positive and Negative Syndrome Scale (PANSS) total scores and rates of extrapyramidal symptoms (EPS). Results: Subjects were 175 patients age 60 years or over with schizophrenia or schizoaffective disorder The mean duration of illness was 365 years. Median doses were 2 mg/day of risperidone and 10 mg/day of olanzapine. PANSS total scores and four of the five PANSS factor scores (positive symptoms, negative symptoms, disorganized thoughts, and anxiety/depression) improved significantly at all time-points and at endpoint in both groups; between-treatment differences were not significant EPS-related adverse events were reported by 9.2% of patients in the risperidone group and 15.9% in the olanzapine group; the between-treatment difference was not significant Total scores on the Extrapyramidal Symptom Rating Scale were reduced in both groups at endpoint; between-treatment differences were not significant Clinically relevant weight gain was seen in both groups, but was significantly less frequent in risperidone patients than in olanzapine patients. Conclusions: Stable elderly patients with chronic schizophrenia receiving appropriate doses of risperidone or olanzapine over an 8-week period experienced significant reductions in the severity of psychotic and extrapyramidal symptoms, with a relatively low risk of side effects.