Objective: There is a major unmet need for effective options in the treatment of bipolar depression.
Method: Five hundred forty-two outpatients with bipolar I (N=360) or II (N=182) disorder experiencing a major depressive episode (DSM-IV) were randomly assigned to 8 weeks of quetiapine (600 or 300 mg/day) or placebo. The primary efficacy measure was mean change from baseline to week 8 in the Montgomery-Asberg Depression Rating Scale total score. Additional efficacy assessments included the Hamilton Depression Rating Scale, Clinical Global Impression of severity and improvement, Hamilton Anxiety Rating Scale, Pittsburgh Sleep Quality Index, and Quality of Life Enjoyment and Satisfaction Questionnaire.
Results: Quetiapine at either dose demonstrated statistically significant improvement in Montgomery-Asberg Depression Rating Scale total scores compared with placebo from week 1 onward. The proportions of patients meeting response criteria (> or =50% Montgomery-Asberg Depression Rating Scale score improvement) at the final assessment in the groups taking 600 and 300 mg/day of quetiapine were 58.2% and 57.6%, respectively, versus 36.1% for placebo. The proportions of patients meeting remission criteria (Montgomery-Asberg Depression Rating Scale < or =12) were 52.9% in the groups taking 600 and 300 mg/day of quetiapine versus 28.4% for placebo. Quetiapine at 600 and 300 mg/day significantly improved 9 of 10 and 8 of 10 Montgomery-Asberg Depression Rating Scale items, respectively, compared to placebo, including the core symptoms of depression. Treatment-emergent mania rates were low and similar for the quetiapine and placebo groups (3.2% and 3.9%, respectively).
Conclusions: Quetiapine monotherapy is efficacious and well tolerated for the treatment of bipolar depression.