One of the major strengths of this study is the use of the alcohol clamp as the method of alcohol administration. The alcohol clamp minimizes the experimental variance in the brain’s exposure to alcohol and makes it possible to maintain long intervals at a target concentration that is the same for all subjects (O’Connor et al., 1998). By avoiding uncertainties associated with gastric emptying and absorption, the method allows the clamp to be established within 20 minutes after beginning ethanol infusion (Ramchandani et al., 1999a). Other strengths of the study include the choice of various SNPs within GABRA2 to predict the responses to alcohol based on findings from recent association studies (Covault et al., 2004; Edenberg et al., 2004; Lappalainen et al., 2005) that yielded highly convergent results of an allelic association with alcohol dependence. In addition, the relatively large number of subjects that participated in this experiment compared with previous study (Pierucci-Lagha et al., 2005) made it possible to examine the separate effects of the alleles by using all 3 genotype groups to examine the responses to alcohol.
