We recruited a heterogeneous sample of low socio-economic status mixed ancestry English or Afrikaans-speaking adolescents (ages 13–15 years) from 12 schools within a 25-km radius of the test site. Screening procedures included a psychiatric and medical history and physical examination (including urine analysis and breathalyzer testing) performed by a psychiatrist (PDC). The Schedule for Affective Disorders and Schizophrenia for School Aged Children (6–18 Years) Lifetime Version (K-SADS-PL) (Kaufman, 1996) was used to ascertain current and past psychiatric diagnoses, as reported by the participants. The Semi-Structured Assessment for the Genetics of Alcohol (SSAGA-II) (Bucholz et al., 1994) was used to confirm AD diagnosis and to obtain detailed substance use histories (alcohol, tobacco, and all other drugs).
