We interviewed and assessed subjects using the Semi-structured Assessment for Drug Dependence and Alcoholism (SSADDA) for psychiatric diagnosis as described previously [Gelernter et al., 2005; Pierucci-Lagha et al., 2005; Pierucci-Lagha et al., 2007]. The five substance dependence (SD) traits included in this study are dependence on alcohol (AD), cocaine (CD), cannabis (CanD), opioids (OD), and nicotine (ND). The diagnosis of each SD trait was based on DSM-IV diagnostic criteria [APA, 1994]. Our study sample was approximately equally divided by sex and subjects ranged in age from 17 to 66 (mean ± SD = 38.9 ± 7.8). Within each SD trait, there were more males among the EA affecteds, who were also younger than AA affecteds. Complete demographic data on study subjects are presented in Table I.
