A second objective of the present study was to examine the association of psychiatric and SUD comorbidity with the utilization of treatment and self-help for cocaine dependence. The severity of cocaine dependence (Kampman et al., 2004) and mental distress (Dennis et al., 2005) has been associated with SUD treatment outcomes. However, the role of psychiatric comorbidity in the utilization of SUD treatment services has not been well studied (Chassler et al., 2006; Grella et al., 2003; Hansen et al., 2004; Van Ness et al., 2004). Cocaine or alcohol dependence severity at entry to SUD treatment has been shown to be associated with less treatment use in the next six months (Carpenter et al., 2002), but the only study examining psychiatric comorbidity found that PTSD was associated with more treatment use and retention (Trafton et al., 2006). The present study was designed to extend those findings by being the first, to our knowledge, to test the relationship between a range of psychiatric comorbidities and SUD treatment utilization.
