Venlafaxine monotherapy in bipolar type II depressed patients unresponsive to prior lithium monotherapy

OBJECTIVE: We examine the safety and efficacy of venlafaxine monotherapy in bipolar type II (BP II) patients with major depressive episode (MDE) who were unresponsive to prior lithium monotherapy. We hypothesized that venlafaxine would be superior to lithium with a low hypomanic conversion rate. METHOD: Seventeen patients who were unresponsive to prior lithium monotherapy were crossed to venlafaxine monotherapy for 12 weeks. The primary outcome was within-subject change in total Hamilton Depression Rating (HAM-D) score over time. Secondary outcomes included the change in Young Mania Rating (YMRS) and clinical global impressions severity (CGI/S) and change (CGI/C) scores. RESULTS: Venlafaxine produced significantly greater reductions in HAM-D (P < 0.0005), CGI/S (P < 0.0005), and CGI/C (P < 0.0005) scores vs. prior lithium. There was no difference in mean YMRS scores between treatment conditions (P = 0.179). CONCLUSION: Venlafaxine monotherapy may be a safe and effective monotherapy of BP II MDE with a low hypomanic conversion rate in lithium non-responders.