Efficacy and safety of olanzapine in the treatment of Japanese patients with bipolar I disorder in a current manic or mixed episode: A randomized, double-blind, placebo- and haloperidol-controlled study

BackgroundNo current data were available regarding the efficacy and safety of olanzapine in Japanese patients with bipolar I disorder with a current manic/mixed episode.MethodsPatients received blindly olanzapine (5-20 mg/day; N = 105), haloperidol (2.5-10 mg/day; N = 20), or placebo (N = 99) for 3 weeks. For the following 3 weeks, the olanzapine and haloperidol groups continued their treatment, while the placebo group switched blindly to olanzapine. The primary efficacy measure was the mean change in Young Mania Rating Scale (YMRS) total score; secondary efficacy measures included bipolar disorder remission rate and switch-to depression. Safety measures included treatment-emergent adverse events (TEAEs), weight and extrapyramidal symptoms (EPSs).ResultsYMRS total score significantly decreased in the olanzapine group compared with the placebo group (− 5.62 [95% CI: − 8.87, − 2.37], p < 0.001) after 3 weeks. Compared with haloperidol, olanzapine was not markedly different in improving overall bipolar symptomatology, and fewer olanzapine-treated patients switched to symptomatic depression (2.4% vs 16.7%, p = 0.014). Overall incidences of TEAEs were not significantly different among the groups, and EPSs in olanzapine group were less severe than in the haloperidol group.LimitationsThe small haloperidol sample size limited the conclusions that can be drawn from the statistical comparisons between the active treatments.ConclusionsThis was the first study to evaluate an atypical antipsychotic in Japanese patients with manic bipolar I disorder. Consistent with previous non-Japanese studies, olanzapine was generally well-tolerated and superior to placebo in improving the severity of manic symptoms. Compared to haloperidol, fewer olanzapine-treated patients switched to symptomatic depression, and EPSs were less severe.