Efficacy of quetiapine in patients with bipolar I and II depression: a multicenter, prospective, open-label, observational study

Jong-Hyun Jeong,1 Won-Myong Bahk,1 Young Sup Woo,1 Ho-Jun Seo,1 Seung-Chul Hong,1 Duk-In Jon,2 Kyung Joon Min,3 Bo-Hyun Yoon41Department of Psychiatry, College of Medicine, The Catholic of University of Korea, Seoul, 2Department of Psychiatry, College of Medicine, Hallym University, Anyang, 3Department of Neuropsychiatry, College of Medicine, Chung-Ang University, Seoul, 4Naju National Hospital, Naju, KoreaPurpose: To evaluate and compare the therapeutic efficacy of quetiapine in bipolar I and II depression patients in the clinical setting.Patients and methods: This was an 8-week, multicenter, open-label, observational study for bipolar depression. The dosage of quetiapine was flexible, and concomitant medications were permitted on clinician's judgments. A total of 1097 patients were enrolled, and 764 bipolar depression patients who exhibited good therapeutic compliance (>75% compliance rate) were analyzed.Results: Clinical Global Impression – Bipolar scale and Montgomery–Asberg Depression Rating Scale scores were significantly improved at weeks four and eight compared with the baseline scores. At the end of the 8-week study, the response rate was 58.9%, and the remission rate was 42.1%. However, there were no significant differences in the response and remission rates between bipolar I and II disorder (BD-I and BD-II) patients (response rate 60.1% versus 56.3%; remission rate 44.5% versus 37.0%). Montgomery–Asberg Depression Rating Scale score at baseline (β = 0.612, P < 0.001), duration of current episode (β = −0.152, P = 0.001), and presence of remission on previous episode (β = 0.111, P = 0.012) were significantly associated with improvements in depressive symptoms. Fatigue (16.0%), somnolence (14.9%), and manic/hypomanic switching (0.6% at week four, 0.3% at week eight) were observed throughout the study period.Conclusion: The results of this study suggest that quetiapine improves depressive symptoms in BD-I and BD-II patients with a minimal incidence of manic switching. The therapeutic efficacy of quetiapine increased with time. Quetiapine could be an effective and safe modality for the treatment of BD-I and BD-II.Keywords: bipolar depression, quetiapine, therapeutic efficacy, observational study