Superior Efficacy of Olanzapine Over Haloperidol: Analysis of Patients With Schizophrenia From a Multicenter International Trial

Background: Previously, a double-blind, 6-week, parallel-group trial compared the therapeutic profiles of olanzapine (5-20 mg/day; N = 1336) and haloperidol (5-20 mg/day; N = 660) in 1996 patients with DSM-III-R schizophrenia (83.1%) or schizophreniform (1.9%) or schizoaffective disorders (15.0%) and showed olanzapine to have a superior, broader spectrum of efficacy as well as a more favorable adverse event profile. The present post hoc analysis examined the efficacy of olanzapine compared with haloperidol in the schizophrenic cohort of that study and in subgroups of schizophrenic patients defined by baseline symptom profile and course of illness. Method: A total of 1658 patients were included. Patients were included in analyses of change if they had both a baseline and at least 1 postbaseline measurement (N = 1622; 1096 olanzapine-treated patients, 526 haloperidoltreated patients). An analysis of variance was used to compare treatment effects on efficacy measurements including the Brief Psychiatric Rating Scale (BPRS; scored 0-6) and the Positive and Negative Syndrome Scale (total, positive subscale, and negative subscale scores). Results: Olanzapine-treated patients exhibited statistically significantly greater improvements from baseline (last observation carried forward) on all efficacy measurements. Olanzapine-treated patients with predominantly positive, predominantly negative, or mixed symptoms had statistically significantly greater improvements in BPRS total scores compared with similar haloperidol-treated patients. Patients with primarily chronic negative symptoms and patients with chronic or subchronic courses of illness had statistically significantly greater mean improvements from baseline on the BPRS total with olanzapine compared with haloperidol. Furthermore, within the olanzapine treatment group, patients with a subchronic course of illness had greater mean improvements than patients with a chronic course of illness. Conclusion: Olanzapine was more effective than haloperidol in treating a varied spectrum of patients with schizophrenia, including patients with positive, negative, or mixed symptom profiles and either a chronic or subchronic course of illness.