Participants underwent genotyping and, at regular intervals, completed measures of level of response to alcohol, parental monitoring, quantity and frequency of alcohol use, and number of alcohol-related problems, and were assessed for alcohol abuse and dependence using Diagnostic and Statistical Manual of Mental Disorders (DSM-IV; APA, 1994) criteria. Participants and parents/guardians provided written informed assent and/or consent. Study materials and procedures were approved by the University of Michigan Medical School Institutional Review Board.
