(McLellan et al., 1992). Composite scores ranged from zero (no problems in the relevant domain) to 1.0 (high severity). We included number of years of regular use based on self-report, recorded at baseline, for alcohol, pain killers, marijuana, stimulants and cocaine (the most prevalent substances of dependence in our sample). Regular use for alcohol was defined as five or more drinks 3 times a week per month or more; regular use for all other substances was defined as three times a week per month or more. We measured whether the patient identified abstinence as his/her goal of treatment at baseline (Mertens and Weisner, 2000; Weisner et al., 2001b).
