REVIEW The comorbidity of tobacco smoking and gambling: A review of the literature DANIEL S. MCGRATH & SEAN P. BARRETT Department of Psychology, Dalhousie University, Halifax, Canada Abstract Issues. Evidence suggests that tobacco smoking and gambling frequently co-occur. Although high rates of comorbid smoking and gambling have been documented in studies with clinical populations of pathological gamblers in treatment, in studies using samples drawn from the community, and in large-epidemiological surveys, little empirical attention has been directed towards investigating the exact nature of this relationship. Approach. In this review, we stress the literature that has examined the epidemiology, aetiology and environmental factors implicated in comorbid smoking and gambling. Publications included in the review were identified through PsycInfo, PubMed and Medline searches. Key Findings. Although conclusive evidence is lacking, a growing body of literature suggests that smoking and gambling might share similar neurobiological, genetic and/or common environmental influences. Implications. Comorbid tobacco smoking and gambling are highly prevalent at the event and syndrome levels. However, research investigating how smoking might affect gambling or vice versa is currently lacking. Conclusion. More studies that examine the impact of this comorbidity on rates of tobacco dependence and problem gambling, as well as implica- tions for treatment outcomes, are needed. [McGrath DS, Barrett SP. The comorbidity of tobacco smoking and gambling: A review of the literature. Drug Alcohol Rev 2009;28:676–681] Key words: comorbidity, addiction, tobacco, smoking, gambling. Introduction A growing body of evidence suggests that tobacco smoking is highly comorbid with gambling. Comorbid smoking and gambling has been documented in studies with clinical populations of pathological gamblers (PG) in treatment, in studies using community-based samples, and in large-scale epidemiological surveys. Despite the frequent co-occurrence of tobacco smoking and gambling, little attention has been directed towards examining the exact dynamics of this relationship. The key aim of this article is to provide an overall review of the empirical literature pertaining to comorbid tobacco smoking and gambling behaviour. In doing so, we have also attempted to stress some of the methodological limitations and gaps in knowledge that currently exist in the literature. This review is organised to first give the reader a broad overview of the extent to which tobacco smoking and gambling co-occur followed by a more focused examination of the literature pertaining to the biological, psychological, social and environmental influences involved in this comorbid relationship. We also discuss the currently available treatment options and the effects of public policies on rates of smoking and gambling. Finally, we raise questions surrounding comorbid tobacco use and gambling that require further empirical investigation. Method The studies incorporated in this review were compiled through keyword searches using several electronic databases including: MEDLINE; PsychINFO; Web of Science; Science Direct; and Proquest. Only empirical Daniel S. McGrath MSc, PhD Candidate, Sean P. Barrett PhD, Assistant Professor. Correspondence to Mr Daniel S. McGrath, Department of Psychology, Dalhousie University, Halifax, NS B3H 4J1, Canada.Tel: (902) 494-3417; Fax: (902) 494-6585; E-mail: daniel.mcgrath@dal.ca Received 22 July 2008; accepted for publication 30 November 2008. Drug and Alcohol Review (November 2009), 28, 676–681 DOI: 10.1111/j.1465-3362.2009.00097.x © 2009 Australasian Professional Society on Alcohol and other Drugs