Genetic and Environmental Influences on Alcohol Use Problems: Moderation by Romantic Partner Support, But Not Family or Friend Support

BACKGROUND: High levels of various forms of social support (e.g., romantic partner, family, friend) have a buffering effect on alcohol use outcomes in both adolescents and adults. The etiological associations among these variables have not been well studied. One possibility is that social support may buffer against inherited genetic predispositions to alcohol problems. Previous work has examined gene-environment interactions (G×E) for alcohol use disorders, but never for social support in adult twins. METHODS: In the current study, biometric modeling techniques were implemented to examine genetic and environmental components of variance of social support and alcohol use problems in a sample of 672 adult twin pairs. Using biometric moderation models that estimate G×E in the presence of gene-environment correlation (rGE), analyses examined how genetic and environmental influences on alcohol use problems varied as a function of romantic partner support, family support, and friend support. RESULTS: Genetic and environmental components of variance for alcohol use problems varied depending on the level of romantic partner support, with greater environmental influences found at the low level of support. Family and friend support, however, failed to show moderating effects. CONCLUSIONS: The current research has implications for expanding our understanding of what types of social support may trigger or suppress genetic and environmental influences on alcohol use problems.