Data were obtained from multiple longitudinal studies designed for genetic epidemiology research. Samples include a national study of adolescents in the US (AddHealth), a birth cohort in the UK (the Avon Longitudinal Study of Parents and Children; ALSPAC), a US study of families densely affected with AUDs (the Collaborative Study on the Genetics of Alcoholism; COGA), two twin birth cohorts in Finland (FinnTwin12 and the older Finnish Twin Cohort [FTC]), and an unselected cohort of university students in the US (Spit for Science; S4S). Data collection included DNA samples for genotyping in addition to interviews or self-report surveys of behavior and mental health, collected at repeated intervals. In the current study, we use data from participants with ancestry similar to European reference panels (hereafter referred to as “EUR”) in order to match the genetic ancestry background of the discovery GWASs (9, 26).
