GSMS is a longitudinal, representative study of children in 11 predominantly-rural counties in southeast United States begun in 1993 (Costello et al., 1996). Three cohorts of children, age 9, 11, and 13 years, were recruited from a pool of ~20,000 children resulting in N=1,420 participants (49% female). Annual assessments were completed with the child and primary caregiver until age 16 and then with the participant again at ages 19, 21, and 24–26 for 9,904 total assessments. These assessments used the Childhood and Adolescent Psychiatric Assessment (Angold & Costello, 2000) and its upward extension. Informed consent forms were completed for all aspects of data collection and the study protocol was approved by the Duke Institutional Review Board. An average of 82% of all possible interviews was completed across all waves, ranging from 75% to 94% at individual waves. Blood spots collected at each observation were used for DNA extraction performed at Rutgers University Cell and DNA Repository. A total of 784 GSMS subjects, contributing 5,766 repeated alcohol consumption assessments, were analyzed in genome-wide association testing. Study characteristics are summarized in Table 1.
