Abstract
OBJECTIVE: Bipolar II disorder is a common, recurrent, and disabling psychiatric illness, and yet little is known about how best to treat it. The pressing clinical need for evidence-based approaches to the treatment of bipolar II disorder, coupled with recent publication of pertinent studies, calls for an updated review of this literature. This review focuses on a critical examination of the evidence supporting the efficacy of treatments for acute depressive episodes in bipolar II disorder. DATA SOURCES: A MEDLINE (via Ovid) search of journals, covering the period from January 1950 to January 2009, was performed to identify relevant studies. Keywords used were bipolar II disorder, bipolar disorder, bipolar depression, and pharmacotherapy. Studies were further limited to those that were in adult samples, published in peer-reviewed journals, and written in English. STUDY SELECTION: We examined all randomized trials evaluating the use of pharmacotherapy in the treatment of acute bipolar II depression. Studies with mixed samples of bipolar I and II or bipolar II and unipolar depression were examined as well. Twenty-one randomized trials were identified and reviewed. DATA EXTRACTION: Therapeutic agents were rated according to the quality of evidence supporting their efficacy as treatments for bipolar II depression. DATA SYNTHESIS: Ninety percent of relevant trials were published after 2005. Quetiapine was judged as having compelling evidence supporting its efficacy. Lithium, antidepressants, and pramipexole were judged as having preliminary support for efficacy. Lamotrigine was considered to have mixed support. CONCLUSIONS: Although progress has been made, further research on bipolar II depression is warranted.