post-hoc findings from this study suggesting that when controlling for urge to drink, carriers of the Asp40 allele drank 4.73 more drinks per episode than Asn40 homozygous and the OPRM1 × urge to drink interaction suggesting that urge to drink was less strongly associated with actual alcohol consumption among carriers of the Asp40 allele. The findings that urge to drink may be a less potent determinant of drinking behavior among carriers of the Asp40 allele is in line with the dissociation between ‘wanting’ and ‘liking’, such that opioid-mediated processes are thought to be less strongly related to the former and more strongly associated with the latter. Despite this apparent consistency with the incentive sensitization approach and its extensive empirical basis, the literature on both of these polymorphisms remains relatively small and the mechanisms underlying their relationship to alcohol use and misuse remain poorly understood.
