Adolescent and parent clinical interviews were reviewed by at least two individuals with advanced clinical training, who were blind to the diagnoses of other family members. This information was used to code, by consensus, every relevant DSM-IV symptom and diagnostic criterion. For the behavior disorders assessed in adolescents, the mother and child reports were combined using the best-estimate method in which a symptom was considered present if endorsed by either reporter23. Diagnoses were considered positive if all (definite) or all but one (probable) of the DSM-IV criteria were met. The disorder symptoms were also summed to provide a quantitative index of clinically significant disruptive behavior. In the parents, nicotine dependence diagnoses were considered positive if present at the definite or probable level. Because the DSM was developed to assess acute rather than lifetime psychopathology, probable diagnoses were included to minimize the likelihood of false negatives due to imperfect recall. Kappa coefficients for our assessments of childhood disruptive disorders are: .73 (ODD), .77 (ADHD), and .80 (CD). Kappa coefficients for substance use disorders, including nicotine dependence, exceed .91.
