Alcohol dependence (AD) is a common psychiatric disorder. The 12-month U.S. prevalence of AD is estimated to exceed 3.8%, which equates to more than 8 million adults (Grant et al., 2004). A variety of adverse consequences are associated with AD. These include medical, social, and legal problems (Caetano and Cunradi, 1997), resulting in an estimated annual cost in the United States of nearly $185 billion (Harwood et al. 1998). Susceptibility to AD is genetically influenced, with heritability estimates ranging from 0.52 to 0.64 (Kendler 2001). Over the past two decades, considerable research has focused on understanding the specific genetic factors contributing to the risk for AD and on the development of medications to treat the disorder (Kranzler et al., in press). There has been a growing convergence between these lines of investigation, with evidence that specific neurobiological systems underlie both the risk for AD and its pharmacological treatment (Knapp et al., 2008).
