Changes in externalizing behaviorsafter children first have an alcoholic drink and first drink heavily

Objective: Proximal changes in externalizing behaviors before and after children and early adolescents have their first alcoholic drink and first heavy drinking episode are examined using intergenerational, prospective data from the ongoing U.K. national Millennium Cohort Study (10,529 child–parent pairs followed over 35,406 occasions). Method: We examined how within-person changes in externalizing behaviors (based on parental reports on the Strengths and Difficulties scale when children were modal ages 5,7,11, and 14 years) follow children’sage at first alcoholic drink(AFD)and age at firstheavy drinking (AFHD), based on confidential child self-reports at ages 11 and 14 years. Analyses controlled for child age, time-varying parent-level confounders (parental education and alcohol abstention), and time-stable selection factors. Results: Estimates from fixed-effects Poisson models revealed a5%increase in the expected count of externalizing behaviors after children have their first alcoholic drink (incidence rate ratio [IRR] = 1.05, 95% CI [1.03, 1.07]), anda13% increase after first drinking heavily (IRR =1.13, 95% CI [1.09, 1.18]), independent of key time-varying and all time-stable individual differences. Conclusions: Early AFHD and unobserved time-stable selection factors partially explain relationships between early drinking and problem behaviors, but early AFD continues to be asignificant predictor of externalizing behavior. Although prevention efforts should continue to discourage heavy drinking in childhood and early adolescence, the results suggest that both AFHD and AFD should be delayed.