Maintenance of response following stabilization of mixed index episodes with olanzapine monotherapy in a randomized, double-blind, placebo-controlled study of bipolar 1 disorder

Background: In a Population of patients with manic and mixed mood episodes, olanzapine has proven effective in maintaining response, as compared to placebo. Whether this is true for the subpopulation of patients with a mixed index episode is not known. Methods: Post-hoc analyses were conducted on data from patients presenting with a mixed index episode who were enrolled in a larger double-blind, placebo-controlled trial. Patients who met remission criteria at 2 consecutive weekly visits during 6 to 12 weeks of open-label olanzapine treatment were randomly assigned to olanzapine or placebo treatment for 48 weeks. The incidence of and time to symptomatic relapse were calculated for any mood episode, and for depressive, manic, hypo-manic, and mixed mood episodes. Results: A total of 121 of 304 patients (39.8%) met criteria for symptomatic remission in the open-label treatment phase and were randomly assigned to olanzapine (n = 76) or placebo (n = 45). Compared to the placebo group, the olanzapine group had a lower incidence of (59.2% versus 91.1%, p<0.001) and a longer time to (46 versus 15 days, p<0.001) symptomatic relapse of any kind. Olanzapine-treated patients also experienced longer time to depressive symptomatic relapse (85 versus 22 days, p = 0.001) and manic symptomatic relapse (too few relapses to calculate versus 42 days, p<0.001) than did placebo-treated patients. Conclusions: Compared with placebo, olanzapine treatment was associated with longer maintenance of response in patients presenting with a mixed index episode of bipolar 1 disorder. (C) 2008 Elsevier B.V. All rights reserved.