This study assessed the effectiveness of motivational interviewing for substance abuse on drug use, retention in treatment, readiness to change, and number of repeat convictions.
Three authors independently assessed studies for inclusion, and two authors extracted data. Results were categorized into (1) MI versus no‐treatment control, (2) MI versus treatment as usual, (3) MI versus assessment and feedback, and (4) MI versus other active treatment. Within each category, we computed meta‐analyses separately for post‐intervention, short, medium, and long follow‐ups. MI can reduce the extent of substance abuse compared to no intervention. The evidence is mostly of low quality, so further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. (Published abstract provided)