“…The stages of change theory provided the theoretical basis for Motivational Interviewing (Miller & Rollnick, 1991; Miller & Rollnick, 2002) and its manualized brief version, Motivation Enhancement Therapy (Miller, Zweben, DiClemente, & Rychtarik, 1992), both widely used and generally effective at fostering reductions in substance use (Babor & Del Boca, 2003; UKATT Research Team, 2005). A focused subset of models conceptually related to RTC have examined motivation for treatment more specifically and its relationship to treatment retention, engagement, and outcomes (Battjes, Onken, & Delany, 1999). These models include the TCU Treatment Motivation model that centers on stages of treatment readiness (Simpson & Joe, 1993) and the Circumstances, Motivation, Readiness, and Suitability model (CMRS; De Leon & Jainchill, 1986; De Leon, Melnick, & Kressel, 1997).…”