Add Health is a nationally representative longitudinal cohort of adolescents who were in grades 7-12 in the US in 1994-95 (Harris, 2013). Participants were identified from 132 schools. The cohort has been followed through the transition to adulthood in five waves, with data collection occurring via in-home interviews. The sample includes siblings. Measures are primarily focused on causes of adolescent health behavior in the multiple contexts of adolescent life. Genetic data were collected in Wave 4. Add Health participants provided written informed consent to participate in the study in alignment with University of North Carolina School of Public Health Institutional Review Board guidelines. Reports between ages 12-17 (n=3,089, 53.71% female) were collected in Wave 1 and Wave 2. Reports between ages 18-25 (n=3,993, 54.30% female) were collected in Wave 3 and Wave 4. Reports after age 26 (n=5,140, 52.98% female) were collected in Wave 3, Wave 4, and Wave 5.
