At our ongoing second follow-up, when the twins are approximately 17 years old, portions of the DICA-R (i.e., ADHD and ODD) are re-administered to the twins and to their primary caretaker. As shown by Barkley et al. (2002), persistence of ADHD may be substantially underestimated if the parental report is dropped during adolescence. However, instruments that are more developmentally appropriate for older adolescents and adults are substituted for other disorders. Because an increase in CD symptoms during adolescence (along with comorbid ADHD) exerts a strong influence on heavy drinking (Molina et al., 2007) and other substance outcomes (Elkins et al., 2007), an interview adapted from the Structured Clinical Interview for DSM-III-R Personality Disorders (Spitzer et al., 1987), assessing DSM-IV and DSM-III-R criteria for antisocial personality disorder (ASPD), has been modified to cover CD since the age-14 follow-up. DSM-IV and III-R substance use disorders are assessed using a modified version of the expanded Substance Abuse Module (SAM) developed by Robins et al. (1987) as a supplement to the WHO's Composite International Diagnostic Interview (Robins et al., 1988). We have added questions
