Major genetic association findings of the current study pertain to subjective responses to alcohol and patterns of alcohol consumption. We detected an epistatic interaction between DAT1 and OPRM1 genotypes where the magnitude of subjective responses for OPRM1 *G carriers was dependent on which DAT1 VNTR was also present. Carriers of both DAT1 A9 and OPRM1 G alleles had higher SHAS and DEQ VAS negative scores when compared to the other three genotype subgroups. In contrast, carriers of both DAT1 A10 and OPRM1 G had the lowest SHAS scores. We did not identify an epistatic interaction between DAT1 and OPRM1 on alcohol-induced stimulation, sedation or the positive subjective effects of alcohol.
