While most studies investigated characteristics of comorbid bipolar and ASUD subjects retrospectively, only a few investigations used prospective data to evaluate the course of both disorders over time by differentiating between bipolar I and II subgroups [review by Rakofsky and Dunlop (10)]. Since there are only a few prospective studies on the clinical course and prognosis of bipolar I and II patients with and without alcohol dependence, the COGA sample (Collaborative study on Genetics in alcoholism) was used to compare these two subgroups of bipolar individuals with and without comorbid alcohol dependence directly. The patients were assessed regarding their lifetime history of ASUD, bipolar disorders and then prospectively re-interviewed after 5 years. In these analyses, both bipolar 1 and II subjects are included to investigate first, the lifetime characteristics of alcohol dependence and bipolar disorders retrospectively and second, the course of alcohol dependence, bipolar disorder and comorbidity with mental and other substance use disorders during a 5-year follow-up period.
