Effectiveness and safety of olanzapine in the treatment of schizophrenia among Asian patients switching from conventional antipsychotics

OBJECTIVES: The objectives of this study were: (1) to investigate, in a clinical practice setting, the effectiveness of olanzapine in the treatment of schizophrenia among partially-responding, symptomatic Asian patients who switch from conventional antipsychotic treatment, (2) to assess the safety of olanzapine and (3) to assess the change in quality of life in Asian patients with schizophrenia who switch to olanzapine. METHODS: Effectiveness, safety and quality of life were assessed in outpatients with schizophrenia (n=1267) who lacked symptomatic control with conventional antipsychotics and were switched to olanzapine therapy. Data for this prospective, observational study were collected for 12 months from Asian patients in China, Hong Kong, the Philippines, South Korea and Taiwan. RESULTS: Significant clinical improvements (P<0.05) were observed following 12 months of olanzapine treatment and 87.3% of the subjects responded to treatment at endpoint (i.e. Brief Psychiatric Rating Scale Total score reduced by > or =30% relative to baseline; last observation carried forward). Abnormal involuntary movements (mean change in Abnormal Involuntary Movement Scale: -3.20, P<0.001) and quality of life were significantly improved in patients treated with olanzapine. However, some patients experienced significant weight gain (3.60+/-4.50 kg, P<0.001) with olanzapine treatment, relative to baseline. CONCLUSIONS: This study shows that switching to olanzapine may be effective in improving symptoms, may be well-tolerated and may improve the quality of life in Asian patients who are only partially responsive to treatment with conventional antipsychotics. The pragmatic design and naturalistic setting of this large study make the findings relevant for treating patients from some Asian countries in routine clinical practice.