Participants were drawn from the third generation of a longitudinal study of familial alcoholism (see Chassin et al. [26] for details). Data were drawn from the sixth wave (referred to as T1) and a follow-up assessment occurring 18 months after the sixth wave (referred to as T2). Adolescents and their parents participated at T1 and only adolescents participated at T2. We included participants who were between 11–17 years old at T1 and 12–18 at T2, had complete genetic data, and were of non-Hispanic Caucasian or Hispanic ethnicity. These inclusion criteria were chosen to capture adolescence, retain as many participants as possible, and reduce heterogeneity in ethnicity. Some adolescents reported fewer lifetime alcohol problems at T2 than at T1 (N = 20), which is a common phenomenon in adolescent substance use research called recanting [47]. Because reasons for recanting are varied (e.g., problems with recall, social desirability), we excluded those cases, resulting in a final sample of N = 292. Compared to those excluded, those included were significantly younger at T2, had significantly higher ancestry scores (higher levels of Hispanic ancestry),
