Venlafaxine Versus Lamotrigine in the Treatment of Bipolar I/II Depression

The primary objective of this study is to assess the efficacy of venlafaxine XR and lamotrigine when each is added to mood stabilizer therapy in patients with acute depressive episodes of bipolar I or Bipolar II disorder. Efficacy of therapy will be evaluated using improvements in clinical symptomatology after 8 weeks of treatment as measured by reductions on the Hamilton Depression Rating Scale (HDRS-29) total score \>50% from baseline. We also would like to assess the efficacy of venlafaxine XR and lamotrigine when each is added to mood stabilizer therapy in improving clinical symptomatology after 8 weeks of therapy as well as to evaluate the side effect profile, safety and tolerability of venlafaxine XR and lamotrigine.