Intensive Motivational Interviewing for Methamphetamine Dependence

A Stage 2 randomized clinical trial (RCT) is proposed to test the efficacy of a promising 9-session model of motivational interviewing (MI) for methamphetamine (MA) dependence. Stage 1 pilot testing indicated the intervention could be easily learned and implemented with fidelity. The sample of 30 MA dependent individuals over 9 weeks showed large reductions in MA use, good retention and consistent attendance. The tailored treatment approach draws upon our previous conceptual papers on MI as well as our experience with a variety of MI protocols, including two Clinical Trials Network (CTN) studies of MI. An innovative feature of the "Higher Dose Motivational Enhancement Therapy" manual is that it comprehensively addresses the issues of clients who have achieved sustained sobriety as well as those still using substances. Thus, it is designed to facilitate treatment entry and engagement as well as maintenance of the gains made in treatment. We posit that a more intensive MI model is necessary to address MA dependent individuals because they frequently present more serious problems than individuals with other substance dependencies and are more prone to lose the gains they make in treatment. MA dependent clients (N=220) will be recruited from New Leaf outpatient treatment in Lafayette, California. This site has a long history of conducting research, including participation in a multi-site study assessing treatment outcome of MA dependence. Study participants will be randomly assigned to 1) a single session of Motivational Interviewing (MI) plus 8 hours of health/nutrition education, or 2) the intensive 9-session MI intervention. In addition to the study interventions, both groups will receive standard outpatient treatment services at New Leaf. Study participants will be assessed weekly during the first 9 weeks of treatment for MA use. More extensive assessments will be conducted at treatment entry and 2-, 4-and 6-month follow-ups. Two therapists will be "crossed" and treat clients in both conditions. Primary outcome measures will be the Timeline Follow Back (TLFB) for MA use, MA urinalysis results, and retention in treatment. Secondary outcomes will include Addiction Severity Index scales and the TLFB for alcohol and other drugs. Exploratory analyses will examine HIV risk behaviors, motivation, and service utilization. A mediation model will build upon MI research by Moyers et al. (2005) and our construct of "supportive confrontation" (Polcin, et al., 2006) by testing whether feedback enhanced with warnings about the potential harm of MA use facilitates the therapeutic alliance, and whether this in turn facilitates better outcome. The significance of the study is highlighted by a recent meta-analysis finding higher doses of MI were associated with better outcomes (Burke et al., 2003). Conversely, several recent studies of standard single session MI with drug dependent clients questioned its effectiveness, while other studies found improvement in retention but not substance use. Clients with MA dependence are good candidates for a more intensive dose of MI because of their severe medical and psychosocial problems. Thus, it is time to test this promising, 9-session MI manual as a useful extension of standard MI for clients with MA dependence.