Placebo-controlled study of quetiapine monotherapy in ambulatory bipolar spectrum disorder with moderate-to-severe hypomania or mild mania.

Background: There are no randomized, placebo-controlled data for quetiapine in outpatients with bipolar spectrum disorder (ambulatory BSD) and moderate-to-severe hypomanic or mild manic symptoms (hypomania/mild mania).

Methods: An 8-week, randomized, double-blind, placebo-controlled trial of quetiapine in ambulatory BSD with hypomanic/mild manic symptoms, defined operationally as a score of >or=3 but <5 on the mania subscale of the Clinical Global Impressions Scale Modified for Bipolar Illness (CGI-BP) at baseline and one prior study visit, at least 3 days but no more than 2 weeks apart. The primary outcome measure was the rate of change in the Young Mania Rating Scale score (YMRS).

Results: During the 8-week study period, patients receiving quetiapine (average daily dose=232mg) had a marginally greater rate of reduction in mean total YMRS score than patients receiving placebo (p=0.06). Additionally, CGI-BP mania (p=0.01) and the CGI-BP overall (p<0.001) scores were significantly reduced and the CGI-depression score (p=0.08) was marginally reduced in the quetiapine group. Six (32%) quetiapine patients and 8 (40%) placebo patients did not complete the trial.

Limitations: Small sample size and high attrition (36%).

Conclusion: Quetiapine was marginally more effective than placebo in reducing hypomanic/mild manic symptoms in ambulatory BSD as assessed by the YMRS. It was more effective than placebo in reducing manic symptoms and global bipolar symptoms as assessed by the CGI-BP. The drug's discontinuation rate was similar to placebo's. Controlled trials of quetiapine and other compounds with mood stabilizing properties in larger groups of ambulatory BSD patients with hypomanic/mild manic symptoms appear warranted.