interview at age 14. Follow up of the intensive subsample when twins were, on average, age 22 (n=1347) included the adult SSAGA. DNA from blood or saliva samples was collected from 1295 twins. Data for the present study is drawn from the psychiatric assessment at age 22 among participants for whom genotypic data were available (n=1170). The sample was 53.6% female (N = 627) and the age range varied from 20–26, with a mean age of 22.42 years (SD=0.72). Participants were fully informed of study procedures and gave written consent to participate. The Helsinki University Central Hospital District’s Ethical Committee and Indiana University’s Institutional Review Board approved the FinnTwin12 study.
