Data on lifetime DSM-IV (American Psychiatric Association, 1994) dependence symptoms were collected using a computerized version of the Composite International Diagnostic Interview – Substance Abuse Module (CIDI-SAM). The CIDI-SAM is regarded as both a reliable and useful diagnostic tool in adolescent and adult samples (Cottler et al., 1989; Crowley et al., 2001; Ustun et al., 1997). Respondents were asked to report whether they experienced one of the following seven DSM-IV dependence symptoms in their lifetime: ‘tolerance’, ‘withdrawal’, ‘substance taken in larger amount and for longer period than intended’, ‘persistent desire or repeated unsuccessful attempt to quit’, ‘much time/activity to obtain, use, recover’, ‘important social, occupational, or recreational activities given up or reduced’, and ‘continued use despite knowledge of adverse consequences’. Participants were assessed for symptoms of alcohol dependence if they reported having consumed alcohol one or more times in their lifetime. Tobacco dependence criteria were assessed in cases where a respondent reported having smoked 20 cigarettes, having smoked a cigar or pipe more than five times, or having used snuff or chewing tobacco more than five times in their lifetime.
