To date, the evidence for a role of the OPRM1 A118 SNP in AUD risk has been mixed, with different studies reporting higher or lower frequency of the G-allele in AUD populations (Berrettini, 2015). The associations of the OPRM1 G-allele in epistatic interactions with DAT1 A9 and. A10 alleles on alcohol sensitivity and heavy drinking frequency in the current study have important implications for AUD risk. Epidemiological studies have identified a strong relationship between frequency of binge and heavy drinking in young adulthood and risk for the development of an AUD later in life (Hasin et al., 2001, Jennison, 2004). Moreover, excessive quantity and frequency of drinking also have strong genetic components, and are key factors contributing to AUD (Kendler et al., 2012). Thus, our data would suggest that the OPRM1 G allele in interaction with DAT1 A9 might contribute to protection against heavy drinking.
