Abstract
Background: Based on the prevalence and health implications of tobacco and cannabis use, aiming to reduce their use, especially among youth, is a sound objective at both the individual and public health level. A proper understanding of the relationships between tobacco and cannabis use may help to achieve this goal. Objectives: To review the relationships between tobacco and cannabis use. Methods: A selective review of the literature. Results: We present an overview of the motivations for tobacco and cannabis use, and their perceived harmfulness. The article then reviews the gateway theory, reverse gateway theory, route of administration theory, and common liability theory. We describe the link between co-use and dependence symptoms, and the substitution phenomenon between tobacco and cannabis use. Three forms of simultaneous use–mulling, blunt smoking, and chasing–and their impacts are explained. We summarize the impact of tobacco use on cannabis (and vice versa) treatment outcomes, and, finally, review new treatments that simultaneously target tobacco and cannabis dependence. Most of the literature reviewed here relates to substance use among adolescents and young adults. Conclusions: The use of tobacco and cannabis–two of the most widely used substances around the world–are strongly intertwined in several respects. Both health professionals and researchers should have well-informed views on this issue to better evaluate, understand, inform, and provide care to their patients.
Acknowledgment
We gratefully thank Richard Poulin, Joanne Muzak, and Maude Royer for their precious help in the preparation of the manuscript.
Declaration of interests
The authors declare that they have no conflict of interest. The authors alone are responsible for the content and writing of the article.