Study subjects were drawn from 540 children and adolescents ages 5 to 18 years (mean 10.6, SD 3.2) and 519 of their parents ascertained from 370 families with ADHD-affected sibling pairs. Detailed descriptions of recruitment methods, screening, and subject assessment have been previously described. 10 Briefly, lifetime psychiatric diagnoses were based on semi-structured diagnostic interviews conducted by master’s level clinical psychologists or highly trained interviewers with extensive experience and reliability training in psychiatric diagnoses. Children and adolescents were assessed using the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime version (K-SADS-PL). Adult parents were assessed using the Schedule for Affective Disorders and Schizophrenia-Lifetime version (SADS-LA-IV), supplemented with the K-SADS Behavioral Disorders module for diagnosis of ADHD and disruptive behavior disorders. Direct interviews were supplemented with parent and teacher versions of the Swanson, Nolan, and Pelham, version IV (SNAP-IV) rating scale, as well as a parent-completed CBCL and Teacher Report Form. Parents also completed current ratings of self and spouse behavior with the ADHD Rating Scale IV. Best estimate diagnoses were assigned using all of the available clinical
