Quetiapine for the treatment of bipolar II depression: Analysis of data from two randomized, double-blind, placebo-controlled studies

Objective. To investigate the efficacy and tolerability of quetiapine monotherapy for depressive episodes in patients with bipolar II disorder. Methods. A post-hoc evaluation was conducted in 351patients with bipolar II depression combined from two similarly designed double-blind, randomized, placebo-controlled, 8-week studies of quetiapine (300 or 600mg/day) that included patients with bipolar I or II disorder (DSM-IV) exhibiting moderate to severe depression. The primary endpoint was change from baseline to week 8 in MADRS total score. Secondary endpoints included HAM-D, HAM-A, and CGI. Results: In patients with bipolar II disorder, improvement in mean MADRS total score from baseline was significantly greater with quetiapine 300 (n=107) and 600mg/day (n=106) from the first assessment (week 1) through week 8 compared with placebo (n=108). The mean change from baseline at week 8 for quetiapine 300 and 600mg/day versus placebo was -17.1 and -17.9 versus -13.3 (P=0.005 and P=0.001 versus placebo), respectively. Change in HAM-D, HAM-A, and CGI were also significantly greater for quetiapine groups versus placebo. Common adverse events in the quetiapine groups included dry mouth, sedation, and somnolence. Conclusion. Quetiapine demonstrated significant efficacy as monotherapy, compared with placebo, for the treatment of acute depressive episodes in bipolar II disorder.