Clinical question

How effective is motivational interviewing in promoting smoking cessation?  

Bottom line

Motivational interviewing seemed effective when given by GPs and by trained counsellors (NNT* 27, range 21Ð250). Longer sessions (>20 minutes per session) were more effective than shorter ones. Two or more sessions of treatment appeared to be marginally more successful than a single session treatment, but both delivered successful outcomes. The evidence for the value of follow-up telephone support was unclear. * NNT = number needed to treat to benefit 1 individual.  

Caveat

These results should be interpreted with caution due to variations in study quality, treatment fidelity and the possibility of publication or selective reporting bias. Critical details in how motivational interviewing was modified for the particular study population, the training of therapists and the content of the counselling were sometimes lacking in trial reports.  

Context

Motivational interviewing is a directive patient-centred style of counselling, designed to help people to explore and resolve ambivalence about behaviour change. It seeks to avoid an aggressive or confrontational approach, and tries to steer people towards choosing to change their behaviour, and to encourage their self-belief. Motivational interviewing was developed as a treatment for alcohol abuse, but may help smokers to quit smoking.  

Cochrane Systematic Review

Lai DTC et al. Motivational interviewing for smoking cessation. Cochrane Reviews 2010, Issue 1. Article No. CD006936. DOI: 10.1002/14651858.CD006936.pub2. This review contains 14 studies involving over 10,000 participants.