Monaz: Hello, I'm Monaz Mehta, editor in the Cochrane Editorial and Methods department. Smoking remains a substantial public health problem around the world and the search for effective ways to help people stop is ongoing, with more than 50 Cochrane Reviews providing evidence on a wide variety of interventions. One of these reviews, on motivational interviewing, was updated in July 2019 and the lead author, Nicola Lindson from the University of Oxford in the UK brings us up to date in this podcast.

Nicole: Motivational interviewing is a type of counselling that can be used to help people to change their behaviour. It aims to help people explore the reasons why they may feel unsure about making behaviour changes and to find ways to make them feel more willing and able to change. Rather than telling someone why and how they should change their behaviour, counsellors try to help them to choose to change their own behaviour, increasing their confidence that they can succeed. Motivational interviewing was first developed by the clinical psychologists William Miller and Stephen Rollnick in the 1980s, when they defined it as "a directive, client-centred counselling style for eliciting behaviour change by helping clients to explore and resolve ambivalence". It has mainly been used to manage health behaviours, such as alcohol abuse, drug addiction, weight loss, treatment compliance, and smoking cessation; and our focus is on the latter.
Our review investigates whether motivational interviewing helps more people to stop smoking than no treatment, or other types of stop smoking treatment. We also looked at whether longer motivational interviewing, with more counselling sessions, helped more people to quit than shorter motivational interviewing with fewer sessions. We also tried to explore whether motivational interviewing for smoking cessation had any effect on people’s well-being, but there was almost no evidence on this and we will need to wait for more studies before even starting to answer this question.
We included 37 randomised studies in the review, involving over 15,000 participants who smoked tobacco. Most studies recruited participants with particular characteristics, often from groups of people who are less likely to seek support to stop smoking than the general population, such as those with substance abuse problems, hospital patients with acute illnesses and young people. The types of motivational interviewing tested across the studies ranged from one to 12 sessions, with the total duration ranging from five to 315 minutes.
Unfortunately, problems with the design of studies, big differences between their findings and the small numbers in some of them meant that the overall quality of the evidence is low. This means that the current evidence base is not sufficient to determine whether motivational interviewing is better than other approaches at helping people to give up smoking or whether more intensive motivational interviewing helped more people to quit smoking than a less intensive form. 
In the end, our conclusions continue to be focused on ways to improve future studies. Such studies need to aim to reduce confounding by minimising the number of interventions provided alongside motivational interviewing, and where co-interventions are used, these should be matched in the comparator arm. Future studies should also maximise the fidelity of motivational interviewing, consider independent monitoring of this, and report these data. Standardising methods used to monitor fidelity across the research field would allow easier comparisons across studies and will make it easier for future updates to this review to provide clear answers on the effects of motivational interviewing.

Monaz: To watch for those future updates, and to read about the state of the current evidence, you just need to visit Cochrane Library dot com and type in a search for 'Motivational interviewing for smoking cessation' to find the review.