Intensive Motivational Interviewing for Methamphetamine Dependence

Study Summary

A Stage 2 randomized clinical trial (RCT) to test the efficacy of a 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 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. MA dependent clients (N=220) were recruited from New Leaf outpatient treatment in Lafayette, California. Study participants were 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 received standard outpatient treatment services at New Leaf. Study participants were assessed weekly during the first 9 weeks of treatment for MA use. More extensive assessments were conducted at treatment entry and 2-, 4-and 6-month follow-ups. Two therapists were "crossed" to treat clients in both conditions. Primary outcome measures included Timeline Follow Back (TLFB) for MA use, MA urinalysis results, and retention in treatment. Secondary outcomes include Addiction Severity Index scales and the TLFB for alcohol and other drugs. A mediation model will build upon MI research proposed by Moyers (2005) and our construct of "supportive confrontation" 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. Clients with MA depe

Primary Outcome

The proportion of days abstinent from methamphetamine was represented by univariate averages at each interview of the overall adjusted longitudinal treatment effects for each of the Standard (SMI) and Intensive (IMI) conditions. For example, a baseline average of 0.55 at baseline represents that study participants were abstinent, on average 55% of the days measured.

Interventions

• BEHAVIORAL Intensive MI
• BEHAVIORAL Single session MI