Motivational interviewing effective in reducing substance abuse

Clinical question: 
How effective is motivational interviewing for reducing substance abuse?
Bottom line: 
People who received motivational interviewing reduced their use of substances more than people who had not received any treatment. However, other active treatments, treatment as usual, and being assessed and receiving feedback were as effective as motivational interviewing. There was not enough data to form conclusions about the effects of motivational interviewing on retention in treatment, readiness to change, or repeat convictions.
Caveat: 
The evidence was mostly of low quality. Motivational interviewing is a brief intervention. Given it involves only 1 to 4 sessions, one should not expect too much regarding changes in drug abuse outcomes. Motivational interviewing and other interventions share a number of non-specific therapeutic factors, such as attention and therapeutic alliance. These factors may have a much greater influence on outcome than the contribution made by approachspecific theory and technique. In an early review of empirical studies cited,common therapeutic factors accounted for 30% of the therapeutic effect, technique 15%, expectancy (placebo effect) 15%, and spontaneous remission 40%.1
Context: 
There are 76.3 million people with alcohol use disorders worldwide and 15.3 million with drug use disorders. Motivational interviewing is a client-centred, semi-directive method for enhancing intrinsic motivation to change by exploring and resolving ambivalence. The client and counsellor typically meet between 1 and 4 times for about 1 hour each time. The intervention is used widely, so, therefore, it is important to determine whether it helps, harms or is ineffective.
Review CD#: 
CD008063
PEARLS No: 
323
Date: 
August, 2011
Authored by: 
Brian R McAvoy