Drug, psychiatric, legal, medical, and social problem severity, were assessed at each interview using the Addiction Severity Index (ASI) (Kaskutas et al., 2003; Mertens and Weisner, 2000; Weisner et al., 2003b; Weisner et al., 2000). The ASI is a widely used instrument that assesses the severity of alcohol, drug, employment, medical, psychiatric, family/social, and legal problems (Mäkelä, 2004; McLellan et al., 1992). In each area, questions are asked that measure the number, frequency, and duration of problem symptoms in the past 30 days, providing a continuous measure from 0 (no problems) to 1.0 (high severity).
