intensive study. All intensive subset parents were interviewed (N=1,860) with a semi-structured psychiatric assessment interview, and at age 14, their twins have been interviewed (N=1,852) with the adolescent version of the same instrument to assess substance use, dependence and psychiatric morbidity) in adolescence. Teachers, parents and peers assessed the externalizing (inattention, impulsivity, and aggressiveness), internalizing (depression and anxiety) and prosocial behaviors of the twins. Figure 2 summarizes the data collection procedures in Finntwin12.
