“…These problems are often closely related to patients' alcohol or drug use behaviors and have been shown repeatedly to have significant negative impacts on treatment retention and subsequent outcomes (McLellan et al, 1994;Simpson, Joe, Fletcher, Hubbard, & Anglin, 1999). Drug use and alcohol use combined with psychiatric illness have been associated with higher health care costs (Westermeyer, Eames, & Nugent, 1998) and with violent behaviors leading to involvement with courts and jails (Ford, Snowden, & Walser, 1991). Analyses from the Drug Abuse Treatment Outcome Study (DATOS) found that, among cocaine-using patients across three modalities of treatment, those with the most severe problems (i.e., substance dependence or polysubstance use, psychiatric illness and social difficulties, criminal justice involvement, income and employment problems, and low social support) had the highest rates of relapse in the year after treatment (Simpson et al, 1999).…”