Associations of Romantic Partners' Characteristics with Alcohol Consumption and Binge Drinking: Examining Evidence for Gene-Environment Interaction.

We investigated associations of romantic partners' alcohol use, cigarette smoking, personality, and psychological distress with alcohol use and binge drinking within a sample of Finnish twins who have initiated alcohol use (N = 1620, 51% female, mean age = 33.6 years) and their romantic partners. We also used twin modeling to examine whether partner characteristics moderate genetic influences on drinking behavior. Having a romantic partner with more frequent alcohol use and smoking was consistently associated with greater alcohol consumption and binge drinking, and partner alcohol use and smoking also moderated genetic influences on alcohol consumption. Further, a range of partner characteristics moderated genetic influences on binge drinking, such that the heritability of binge drinking was higher when partners reported less frequent alcohol use, greater smoking, lower conscientiousness, and higher extraversion, neuroticism, and psychological distress. These findings highlight the important, but complex, ways in which romantic partners contribute to drinking behavior.