Objectives: To investigate the efficacy and tolerability of quetiapine monotherapy in patients with bipolar I or II disorder with a rapid-cycling disease course.
Methods: Adult patients with a DSM-IV diagnosis of bipolar disorder, most recent episode depressed, with a rapid-cycling disease course from a previously completed multicenter trial randomized to 8 weeks of treatment with quetiapine 600 mg/day (n = 31), quetiapine 300 mg/day (n = 42), or placebo (n = 35) were included in this sub-analysis. The primary efficacy variable was change from baseline to week 8 in Montgomery–Asberg Depression Rating Scale (MADRS) total score.
Results: Quetiapine (600 and 300 mg/day) provided significantly greater mean reductions from baseline to week 8 in the MADRS total score than placebo (−21.1, −20.7 versus −11.6, both p < 0.001) in this patient population. Effect sizes in patients with a rapid-cycling disease course were 1.2 (600 mg/day) and 1.1 (300 mg/day) and were similar for bipolar I (0.98 and 1.22) and bipolar II (1.45 and 0.97) sub-groups. Significant improvements were also noted on the Clinical Global Impression, Hamilton Rating Scale for Depression, Hamilton Rating Scale for Anxiety, Pittsburgh Sleep Quality Index, and Quality of Life Enjoyment and Satisfaction Questionnaire scales. Quetiapine was generally well tolerated with moderate increases in weight and extrapyramidal side effects compared to placebo. The incidence of treatment-emergent mania was similar to placebo.
Conclusions: Quetiapine monotherapy (600 or 300 mg/day) is clinically effective and well tolerated in the short-term treatment of depressive episodes in patients with bipolar I or II disorder who have a rapid-cycling disease course.