The Center on Antisocial Drug Dependence (CADD) sample was recruited as a longitudinal study designed to study the genetics of adolescent drug abuse. For the current analysis we focused on subjects recruited through the family portion of this study who were 17 years or older at the time of assessment. Details regarding sample ascertainment and exclusion criteria have been described previously (Stallings et al. 2005; Stallings et al. 2003). Briefly, clinical probands were recruited from residential and outpatient treatment facilities in the Denver metropolitan area operated by the Department of Psychiatry, University of Colorado School of Medicine. Clinical probands were drawn from individuals with consecutive admissions to the treatment facilities between February 1993 and June 2001. Community based probands were recruited to be matched to clinical probands based on age, gender, ethnicity, and zip code. All individuals living in the same household as the proband were asked to participate in the study. The CADD is currently in its 3rd wave of data collection. For the current study, data collected during wave 2 were included in the analysis. If the subjects
