Effect of quetiapine XR on depressive symptoms and sleep quality compared with lithium in patients with bipolar depression

Background: Bipolar depression is one of the most serious psychiatric conditions. In addition, sleep disturbance in bipolar disorder is common, and therapeutic agents restoring sleep disturbances in bipolar disorder patients will be clinically beneficial. In the current study, we compared the effect of quetiapine XR with lithium on depressive symptoms and sleep in bipolar depression patients during 8 weeks of trial. Methods: An open-label, randomized comparison of sleep-activity and depressive symptoms between 8-week quetiapine XR monotherapy and lithium monotherapy for bipolar depression was conducted. Each assessment consisted of HDRS-17, Clinical Global Impression-severity (CGI-S), and self-reported Pittsburgh Sleep Quality Index (PSQI). Actigraphy-measured sleep parameters were assessed. Results: A total of 42 patients (35.7 +/- 10.9 years; gender: male 15, female 27) with bipolar depression were screened out. Out of 42 patients, six patients were excluded before randomization. After randomization, seven patients were withdrawn. Twenty-nine patients with more than two visits after randomization (lithium group: 17, quetiapine XR group: 12, mean age: 36.1 +/- 104, gender: male 13, female 16) were included in the final analysis. In both groups, Hamilton Depression Rating Scale (HDRS) scores were significantly decreased at weeks 1, 2, 4, 6, and 8 compared with baseline. Remission rate (HDRS <= 7) in the quetiapine XR was significantly higher than that of the lithium group. In the quetiapine XR group, PSQI scores at weeks 1, 2,4, 6, and 8 was significantly decreased compared with baseline. Sleep efficiency at weeks 6 and 8 was significantly increased. WASO at week 8 was significantly decreased. Limitations: First, the present study was conducted with the relatively small number of study subjects. Second, bias could have affected the study results due to its open-label design. Third, study subjects were made up of high proportion of bipolar II disorder patients. Conclusions: Quetiapine XR monotherapy was more effective in treating bipolar depression than lithium. In particular, quetiapine XR treatment improved both subjective and objective sleep quality in patients with bipolar depression. However, relationship between favorable sleep quality and depressive symptom improvement were limited. (C) 2014 Elsevier B.V. All rights reserved.