Motivational interviewing aims to help people explore and deal with their mixed feelings about changing their behaviour and to increase their motivation to make positive changes. It has become increasingly popular over the last decade and is used in psychotherapy, medicine, treating addictions and public health. Brad Lundahl from the University of Utah and Brian L. Burke from Fort Lewis College reviewed a number of studies into the effectiveness of motivational interviewing and found that it was significantly better than not treating people at all and as effective as other methods of treatment at helping people overcome drug problems and reduce risky behaviour. Group motivational interviewing was found to be less effective than one-to-one interviewing.
Lundahl, Brad and Burke, Brian L. - The effectiveness and applicability of motivational interviewing: a practice-friendly review of four meta-analyses Journal of Clinical Psychology November 2009, 65(11), 1232-1245