Olanzapine for patients with treatment-resistant schizophrenia: A naturalistic case-series outcome study

Objective: This prospective, consecutive case-series outcome investigation evaluates the effectiveness olanzapine in 16 patients with treatment-resist ant schizophrenia. Method: Treatment resistance was defined as nonresponsiveness to at least 3 antipsychotic drugs from at least 2 different chemical classes. A minimum baseline score on the Brief Psychiatric Rating Scale (BPRS) of 45 was requi red for enrolment. Outcome evaluation measures included the BPRS, Global As sessment Scale (GAS), and Abnormal Involuntary Movement Scale (AIMS). Results: Subjects (n = 16) had a mean age of 40 years and mean duration of illness of 16 years. Olanzapine treatment was initiated at 5 mg daily and w as increased based on clinical judgement up to a maximum of 40 mg daily. Si gnificant decreases in mean BPRS (P < 0.001) and GAS (P < 0.01) scores were observed at weeks 4, 8, 12, and 16, compared with baseline. Eight of 16 pa tients responded to olanzapine, as defined by a 20% decrease in BPRS score by week 16. Dyskinetic movements significantly increased at week 4 (P < 0.0 1) but did not differ from baseline at weeks 8 and 16. Conclusion: These results suggest that olanzapine at moderate to high doses may offer an effective treatment for a significant proportion of patients with schizophrenia nonresponsive to multiple trials of conventional antipsy chotics. A randomized controlled trial is encouraged to validate these find ings, and comparative trials are required to determine when clinicians shou ld consider this approach.