Impact of quitting smoking and smoking cessation treatment on substance use outcomes: An updated and narrative review.
Historically, smoking cessation was thought to negatively impact substance use outcomes among smokers who use other substances. We sought to synthesize recent reports on this association.



Google Scholar, PubMed, and Cinahl were searched for studies published from 2006 to March 29, 2016 that reported impact of smoking cessation treatment or quitting smoking on substance use or substance use disorder treatment outcomes in the general population and among those in substance abuse treatment. Studies were grouped by reported impact as follows: "positive" (i.e. improved), "null" (i.e. no change), or "negative" (i.e. worsened).



Twenty-four studies were included. Eighteen reported the impact of quitting smoking and six reported the impact of smoking cessation treatment intervention, independent of quitting, on substance use outcomes. Eleven studies (46%) reported solely positive impact; four (17%) reported solely null impact; eight (33%) reported mixed positive and null impact by analysis (combined and subgroup, n=1); substance (n=4); length of follow-up (n=2); and comparison group (n=1). One study (4%) reported mixed negative and null impact by ethnic group. No studies reported increased substance use.



Smoking cessation does not appear to have a negative effect, and often has a positive effect on substance use outcomes. Smoking cessation advice should be offered, without hesitation, to smokers who report substance use and those in treatment for substance use disorder.
Center for Tobacco Control Research and Education, University of California San Francisco, 530 Parnassus Avenue, Suite 366, San Francisco, CA 94143, USA. Electronic address: Karma.McKelvey@ucsf.edu.
Karma
K
McKelvey
Center for Tobacco Control Research and Education, University of California San Francisco, 530 Parnassus Avenue, Suite 366, San Francisco, CA 94143, USA.
Johannes
J
Thrul
Center for Tobacco Control Research and Education, University of California San Francisco, 530 Parnassus Avenue, Suite 366, San Francisco, CA 94143, USA; Department of Psychiatry and Weill Institute for Neurosciences, University of California San Francisco, 401 Parnassus Avenue, Box TRC 0984, San Francisco, CA 94143, USA.
Danielle
D
Ramo
D006801:Humans; D016540:Smoking Cessation; D019966:Substance-Related Disorders / Q000628:therapy*; D000073869:Tobacco Smoking / Q000628:therapy*
Smoking cessation; Smoking cessation treatment; Substance use; Substance use disorder; Substance use treatment