Participants in the present study are the European-American subsample (n = 324) of the Child Development Project (CDP) for whom parental externalizing, life events, adolescent externalizing, and GABRA2 genotype information were available. The original CDP sample included 585 children who were recruited from public schools in Nashville and Knoxville, Tennessee and Bloomington, Indiana. Since enrolling in the study, participants have been contacted annually for follow-up assessments of their social development and emotional and behavioral adjustment. As described in greater detail in Dick et al. (2009), DNA data were collected in the context of an annual follow-up visit in early adulthood. Analyses were limited to the European-American participants (n = 477 from the full sample) for whom relevant phenotypic data were also available (n = 324; 50% male) because allele frequencies and linkage disequilibrium structures often differ across populations.
