Comparison of treatment-emergent extrapyramidal symptoms in patients with bipolar mania or schizophrenia during olanzapine clinical trials

Background: Previous research on pharmacotherapy with conventional antipsychotics has suggested that patients with affective disorders have higher rates of treatment-emergent extrapyramidal symptoms (EPS) than patients with schizophrenia. It is not known whether this differential vulnerability holds true for treatment with atypical antipsychotics such as olanzapine. The present analysis retrospectively examined olanzapine clinical trial data for incidence of treatment-emergent EPS in patients with either schizophrenia or bipolar disorder. Method: Study participants were 4417 patients meeting DSM-III or DSM-IV criteria for either schizophrenia or bipolar mania participating in olanzapine clinical trials through July 31, 2001. Data were pooled across haloperidol-controlled trials and separately across placebo-controlled trials. Measures of EPS included rates of treatment-emergent EPS adverse event by type (i.e., dystonic, parkinsonian, or residual), Simpson-Angus Scale score mean change, rates of treatment-emergent parkinsonism, and rates of anticholinergic use. Results: Consistent with prior research, haloperidol-treated patients with bipolar disorder appeared to be more vulnerable to the development of EPS than those with schizophrenia. However, olanzapine-treated patients with bipolar disorder were no more likely to develop EPS than those with schizophrenia. Conclusion: Results support previous research regarding conventional antipsychotics and suggest that olanzapine therapy does not increase the risk of EPS for patients with bipolar disorder.