Bipolar II disorder (BDII) is a serious condition characterized by depressive and hypomanic episodes. The disability and suicide risk associated with BDII is equal to bipolar I disorder. However, there are no clinical trials for BDII, nor is the treatment of BDII addressed in current treatment guidelines. Data suggest that Li and LTG may be effective treatment options for BDII. This study will determine the safety, effectiveness, and tolerability of the two drugs in people with BDII.