Abstract
Research suggests that people adapt their own drinking behavior to that of others. Studies have shown that when being in the company of a heavy drinking peer, individuals tend to drink substantially more than when being with a non-drinking or light-drinking peer. However, not everyone is equally susceptible to other people’s drinking behavior. Based on genetic differences some individuals might be more inclined to adapt their own level of alcohol consumption to that of other people. In this study we used a 3 (drinking condition) by 2 (genotype) experimental design to test whether higher susceptibility to alcohol-related cues (i.e. seeing someone drink) was related to the DRD4 VNTR 7-repeat polymorphism (N = 113). A strong gene-environment interaction showed that participants carrying at least one copy of the 7-repeat allele consumed substantially more alcohol in the presence of heavy-drinking others than those without the risk allele. This study highlights that individual variability in sensitivity to other people’s drinking behavior may be attributed to genetic differences. Carrying the 7-repeat allele may increase the risk for heavy alcohol use when in the company of heavy-drinking peers.
