The sample consisted of participants from the younger cohort in the longitudinal Minnesota Twin Family Study (MTFS, see Iacono & McGue, 2002). Participants are identified by the target age for their intended assessment: 11-years-old (M=11.70, SD=0.43) at intake, 14-years-old (M=14.77, SD=0.51) at the first follow-up, and 17-years-old (M=17.99, SD=0.60) at the second follow-up. The final sample of those who were administered the relevant measure in person included 710 males and 676 females at intake. At first follow-up, 608 males and 648 females completed the measure and data were available from 493 males and 504 females at second follow-up.
