Alcohol and tobacco use behaviors were assessed during a face-to-face structured interview including an adaptation of the Composite International Diagnostic Interview – Substance Abuse Module (CIDI-SAM) (Cottler and Keating, 1990). Nicotine dependence was assessed using DSM-IV criteria. The seven symptoms with their respective endorsement rates are given in Table 2. An individual was considered dependent if they endorsed three or more symptoms. Two phenotypes were analyzed: nicotine dependence as defined by three or more DSM-IV dependence symptoms, and reported number of unsuccessful quit attempts. The number of unsuccessful quit attempts was used because it is a quantitative measure and was hypothesized to be a closer biological measure of addiction (than overall dependence). Phenotypes were examined for ethnic and sex differences using ANOVA in SPSS.
