This study examined the moderating effects of the A118G SNP of the OPRM1 gene on subjective responses to alcohol in a sample of alcohol dependent patients. Consistent with the findings from heavy drinking samples (Ray and Hutchison, 2004; Ray et al., 2010c), clinically-diagnosed alcohol dependent G-allele carriers reported greater sensitivity to the stimulant and hedonic effects of alcohol. The use of an alcohol infusion to minimize pharmacokinetic variation and the addition of a placebo infusion are important as they allow for greater confidence in attributing these results to the pharmacological effects of alcohol. Moreover, the extension of these findings to a sample of individuals with alcoholism is important given that much of the mixed findings for the role of this polymorphism in alcoholism etiology and treatment may be due to heterogeneity across samples and endpoints.
