The Emerging Evidence Base for Motivational Interviewing: A Meta-Analytic and Qualitative Inquiry

This article offers a meta-analytic, qualitative, and process review of the empirical literature for adaptations of motivational interviewing (AMIs), a promising approach to treating problem behaviors. AMIs are equivalent to other active treatments and yield moderate effects (from 0.35 to 0.56) compared to no-treatment/placebo for problems involving alcohol, drugs, and diet and exercise. Results do not support the efficacy of AMIs for smoking or HIV-risk behaviors. Conclusions regarding the mechanisms of action for AMIs are limited by methodological problems: confounding motivational interviewing with feedback, unclear definitions of the AMI interventions used, difficulties in therapist training, and limited use of treatment integrity rating scales. Extant research suggests that AMIs are equivalent in efficacy to and briefer than cognitive behavioral skills training (CBST) approaches. Since AMIs focus on readiness to change while CBST targets the change process, AMIs may be useful as preludes or additions to CBST.