Venlafaxine versus lithium monotherapy of rapid and non-rapid cycling patients with bipolar II major depressive episode: a randomized, parallel group, open-label trial.

BACKGROUND There is a paucity of controlled clinical data on the best initial therapy for treating patients with bipolar type II (BP II) major depressive episode (MDE). In this analysis, we examined the safety and antidepressant efficacy of short-term venlafaxine versus lithium monotherapy in rapid and non-rapid cycling patients with BP II MDE. We hypothesized that lithium would have superior efficacy to venlafaxine, with fewer syndromal and sub-syndromal hypomanic and mixed mood conversions in the rapid cycling BP II MDE patients. METHODS Patients were randomized to monotherapy with either venlafaxine 37.5-375 mg daily or lithium 300-2100 mg daily for 12 weeks. The primary outcome measure was the 28-item Hamilton Depression Rating (HAM-D 28), with embedded 'typical' HAM-D 17 and 'atypical' HAM-D 17-R symptom scores. Secondary outcomes included the Young Mania Rating Scale (YMRS), clinical global impressions severity (CGI/S) and change (CGI/C) ratings, the proportion of responders (with > or =50% reduction in baseline HAM-D score) and remitters (with a final HAM-D score or =4 affective episodes per year). We did not employ a patient-recorded daily chrono-record to identify ultra-short mood conversions. The study used a randomized, parallel group, open-label design. CONCLUSION These observations from this exploratory analysis suggest that venlafaxine monotherapy may be more effective than lithium monotherapy, with a similar mood conversion rate, in rapid and non-rapid cycling patients with BP II MDE. These data support prior observations that venlafaxine monotherapy may be effective initial treatment for BP II MDE.