Associations between oxytocin receptor gene (OXTR) polymorphisms and self-reported aggressive behavior and anger: Interactions with alcohol consumption

Oxytocin has been implicated in the regulation of social as well as aggressive behaviors, and in a recent study we found that the effect of alcohol on aggressive behavior was moderated by the individual's genotype on an oxytocin receptor gene (OXTR) polymorphism (Johansson et al., 2012). In this study we wanted to deepen and expand the analysis by exploring associations between three (rs1488467, rs4564970, rs1042778) OXTR polymorphisms and aggressive behavior, trait anger as well as anger control in a population-based sample of Finnish men and women (N = 3577) aged between 18 and 49 years (M = 26.45 years, SD = 5.02). A specific aim was to investigate if the polymorphisms would show interactive effects with alcohol consumption on aggressive behavior and trait anger, as well as to explore whether these polymorphisms affect differences in anger control between self-reported sober and intoxicated states. The results showed no main effects of the polymorphisms, however, three interactions between the polymorphisms and alcohol consumption were found. The effect of alcohol consumption on aggressive behavior was moderated by the genotype of the individual on the rs4564970 polymorphism, in line with previous results (Johansson et al., 2012). For trait anger, both the rs1488467 and the rs4564970 polymorphisms interacted with alcohol consumption. It appears that the region of the OXTR gene including both the rs4564970 and the rs1488467 polymorphisms may be involved in the regulation of the relationship between alcohol and aggressive behavior as well as between alcohol and the propensity to react to situations with elevated levels of anger.