Does lower response to alcohol explain the high co-morbidity between bipolar disorder and alcohol dependence?

The frequency of the co-occurrence between alcohol use disorders and bipolar disorder is well documented. However, the etiology of this association is discussed. Among the most quoted hypothesis, high alcohol consumption has been considered as a form of self-medication. At variance with this assumption, we hypothesized that mania is associated with a low level of response to alcohol. Indeed, a low level of response to alcohol was previously associated with an increased risk of alcohol dependence in a high risk population. We discuss the neurobiological findings supporting our assumption, including the decreased reward-related brain activation in mania and further propose a brief study design to test this hypothesis.