John: Several dozen Cochrane Reviews examine the effects of methods to help people quit smoking. A new review in November 2016 adds to this evidence by considering interventions targeted at people with substance use disorders. We asked lead author, Dorie Apollonio from the University of California San Francisco in the USA, to tell us what they found in this podcast.

Dorie: Smoking rates are especially high among people who are dependent on alcohol or other drugs, but those being treated for these addictions are not usually offered treatment to help them stop smoking at the same time. This is because of concern that trying to stop smoking might make people in treatment less likely to recover from other addictions. We wanted to see if this is true and to investigate whether providing tobacco cessation interventions increased the likelihood that people in treatment for or recovery from drug dependence would quit smoking. We also looked at whether tobacco cessation interventions had any effects on the likelihood of recovering from other drug addictions.
We found 34 randomized trials of treatments to quit smoking among people in treatment for or recovery from other drug dependence, involving approximately 5800 participants in five countries; and the results are promising. However, we felt that the overall quality of the evidence was low, because many studies did not give enough detail about the methods that they used. The studies also considered very different types of treatment, making it difficult to do comparisons between them.
The types of smoking cessation treatment tested included: counselling (which might be a brief advice session or multiple sessions of behavioral support, either individually or in a group); medicine (called pharmacotherapy; including nicotine replacement therapy, with or without other medicines that help smokers to stop smoking); or a combination of counselling and pharmacotherapy. We combined the results of trials separately for each of these types of treatment, although different trials used different treatments. People who were in the control groups received usual care, brief advice about quitting smoking, or were put on a waiting list to receive the tested treatment later. Most trials assessed the number of people who had quit smoking at least six months after beginning treatment, but we also included some studies with a shorter follow-up.
Eleven studies with a total of 1800 people tested the effects of pharmacotherapy, providing some evidence that people given pharmacotherapy were more successful at quitting smoking. On the other hand, 11 studies with a similar number of people that tested counselling against usual care did not show evidence of a benefit of counselling alone. Finally, there was evidence that people given combined pharmacotherapy and counselling treatments were more successful at quitting smoking, based on twelve studies with 2200 participants.
We were able to use data from 2231 people in eleven studies to investigate the effect of tobacco cessation interventions on the use of alcohol and other drugs, and found that providing these interventions did not make people more likely to return to using alcohol or other drugs.
Overall, the results suggest that treatment to help people stop smoking should be incorporated into programs addressing alcohol and other drug dependence. Our review has found that providing tobacco cessation interventions to smokers in treatment for or recovery from alcohol and other drug dependencies makes them more likely to quit smoking, and that the interventions don’t affect their likelihood of recovering from these other addictions.

John: If you would like to learn out more about these results, including separate findings for people who were addicted to alcohol or to drugs such as heroin, you can find it online at Cochrane library.com with a search for ‘smoking cessation and substance abuse’.