Co-development of alcohol use problems and antisocial peer affiliation from ages 11 to 34: selection, socialization and genetic and environmental influences

Background and aims: Social context is an important factor in determining the developmental trajectory of alcohol use. We examined the co-development between alcohol use problems and antisocial peer affiliation. We also estimated the genetic and environmental influences on alcohol use problems, antisocial peer affiliation and their co-development over time. Design: Longitudinal study using bivariate latent basis models with structured residuals (LBM-SR). A biometric model was then fitted to estimate the genetic and environmental influences on the growth factors and their covariances. Setting: The United States mid-west region. Participants: Members of the Minnesota Twin Family Study (MTFS), an ongoing, longitudinal study of 3762 (52% female) twins (1881 pairs). Measurements: Alcohol use problems were assessed using a composite measure of average number of drinks per occasion in the past 12 months, maximum number of drinks in 24 hours and DSM-III-R symptoms of alcohol abuse and dependence. Antisocial peer affiliation was measured by self-report of the proportion of one's friends who exhibited types of antisocial behaviors. Findings: The LBM-SR model revealed that there was a large correlation between the growth factors for alcohol use problems and antisocial peer affiliation [r = 0.78, 95% confidence interval (CI) = 0.76, 0.80] and cross-lagged effects consistent with both selection and socialization effects. Additionally, antisocial peer affiliation in adolescence was associated with greater increases in alcohol use problems over time (r = 0.57, 95% CI = 0.54, 0.60). Genetic influences largely accounted for the association between antisocial peer affiliation in pre-adolescence and growth in alcohol use problems, while shared environmental influences accounted for the correlation between antisocial peer affiliation and alcohol use problems growth factors. Conclusions: Antisocial peer affiliation in adolescence appears to be a salient, genetically influenced risk factor for early alcohol use and increase in alcohol use from adolescence to young adulthood.