of variation in the GABAAα6 and serotonin transporter in the subjective response to alcohol in the laboratory (Corbin, Fromme, and Bergenson, 2006; Fromme et al., 2004; Schuckit et al., 1999). In a recent review of the literature on genes contributing to low level of response to alcohol, Schuckit, Smith, & Kamijin (2004) highlighted several candidate gene findings with possible pharmacodynamic effects on level of response to alcohol and alcoholism risk. These findings included genes relating to alterations in the GABAergic system, with a particular focus on GABAA and its subunits, the serotonin transporter gene, opioid and cannabinoid systems, and genes involved in second messenger systems (e.g., G proteins and protein kinases) (Schuckit, Smith, & Kamijin, 2004). These authors concluded that there is evidence to support the benefits of conducting genetic studies, both linkage and association, on subjective responses to alcohol as an endophenotype for alcoholism. As suggested by Schuckit and colleagues (2004), the ultimate goal of this line of research is to identify genes that underlie alcohol-related phenotypes, such as level of response to alcohol, and evaluate genetic factors that interact with environmental factors to determine the risk for alcoholism, which in turn can be translated into improved treatment approaches.
