Abstract: Eighty-three studies, 36 of which were new to this update, met the inclusion criteria, representing 29,536 participants. Overall, we judged 16 studies to be at low risk of bias and 21 studies to be at high risk of bias. All other studies were judged to be at unclear risk of bias. Results were not sensitive to the exclusion of studies at high risk of bias. We pooled all studies comparing more versus less support in the main analysis. Findings demonstrated a benefit of behavioural support in addition to pharmacotherapy. When all studies of additional behavioural therapy were pooled, there was evidence of a statistically significant benefit from additional support (RR 1.15, 95% CI 1.08 to 1.22, I² = 8%, 65 studies, n = 23,331) for abstinence at longest follow-up, and this effect was not different when we compared subgroups by type of pharmacotherapy or intensity of contact. This effect was similar in the subgroup of eight studies in which the control group received no behavioural support (RR 1.20, 95% CI 1.02 to 1.43, I² = 20%, n = 4,018). Seventeen studies compared interventions matched for contact time but that differed in terms of the behavioural components or approaches employed. Of the 15 comparisons, all had small numbers of participants and events. Only one detected a statistically significant effect, favouring a health education approach (which the authors described as standard counselling containing information and advice) over motivational interviewing approach (RR 0.56, 95% CI 0.33 to 0.94, n = 378). There is high-certainty evidence that providing behavioural support in person or via telephone for people using pharmacotherapy to stop smoking increases quit rates. Increasing the amount of behavioural support is likely to increase the chance of success by about 10% to 20%, based on a pooled estimate from 65 trials. Subgroup analysis suggests that the incremental benefit from more support is similar over a range of levels of baseline support. More research is needed to assess the effectiveness of specific components that comprise behavioural support.

Plain-language summary: We looked for studies that included smokers and provided or offered medication to everyone. People in the studies were then randomly split into groups which received different amounts or kinds of behavioural support. To assess whether the support given helped people to quit, the studies had to count the number of people not smoking after six months or more. We did not look at studies that only included pregnant women. We searched for studies in June 2018. We included 83 studies, with almost 30,000 people. Most studies included people who wanted to quit smoking, but a small number of studies offered support to people who were not trying to quit. Combining results from 65 trials suggested that increasing the amount of behavioural support for people using a stop-smoking medication increases the chances of quitting smoking. About 17% of people in the groups receiving less or no support quit smoking, compared to about 20% in the groups receiving more support. Providing some support via personal contact, face-to-face or telephone, is helpful. Few studies compared different types of support. More research is needed to find out if some types of behavioural support help more people using medication to quit smoking. We judged the overall quality of evidence to be high, meaning further research is very unlikely to change our results. This review has been updated twice and both times the findings remained very similar, even though many new studies were added.