Missouri Adolescent Female Twin Study is a longitudinal investigation of alcohol-related problems and associated psychopathology in female adolescence and young adults. Twins born to Missouri-resident parents between July 1, 1975 and June 30, 1985 were identified through birth records and recruited from 1995 to 1999. Cohorts of 13, 15, 17, and 19 year-old twin pairs and their families were ascertained. Parental diagnostic interviews were collected at baseline in 78% of the families recruited and found eligible for participation. Baseline (Wave 1) interviews were completed with 3258 twins. Wave 3 retest interviews were conducted with a subset of Wave 1 participants (n = 1370) two years after Wave 1 assessments. (Data were not drawn from Wave 2 interviews, as they did not cover all domains of interest.) Wave 4 assessments were conducted from 2002 to 2005 with 3787 participants (80% of twins identified from birth records) and contained detailed trauma history assessment. Data from Waves 1 and/or 3 were available for 95.5% of Wave 4 participants which included 2176 monozygotic (57.5%) and 1611 di-zygotic (42.5%) female twins. Ages of the female
