The results of a study in the Journal of Clinical Psychiatry indicated that cannabis use was significantly correlated with various smoking habits, including beginning to smoke cigarettes, continuing to smoke cigarettes, and relapsing after cessation.
The authors analyzed data on 34,639 adults who responded at waves 1 (2001-2002) and 2 (2004-2005) of the National Epidemiologic Survey on Alcohol and Related Conditions, which included items on cannabis use and cigarette use, cessation, and relapse.
The study defined nonsmokers as individuals who had <100 lifetime cigarettes, former smokers as individuals who had ≥100 lifetime cigarettes but did not smoke at wave 2, and current daily and nondaily smokers as individuals with ≥100 lifetime cigarettes who smoked at wave 2.
Cannabis users were significantly more likely than nonusers to begin smoking, continue smoking, and relapse after quitting, regardless of their smoker status at wave 1. Wave 1 nonsmokers with past-year cannabis use were twice as likely to report nondaily smoking at wave 2. These findings remained significant after controlling for health and social demographics, but were less notable after controlling for other substance use disorders.
Prior studies have found a relationship between cannabis use disorders and cigarette use, but few respondents at wave 1 had received such a diagnosis. Thus, the findings of these analyses suggest that, to an extent, this relationship might be generalized to cannabis users as a whole, not just those diagnosed with a cannabis use disorder.
One reason for the overlap between cigarette and cannabis use, the authors proposed, is because the substances can be easily coadministered. With the increase of cannabis use in the United States — an average of 7000 new users per day in 2014 — the authors emphasized the importance of continued research into risks associated with cannabis use.
The investigators cautioned that they could not confirm cannabis or cigarette use in the survey’s respondents. Additionally, they noted that the use of other or multiple drugs might account for the difference in cigarette smoking habits, reducing the significance of cannabis’s influence alone.
Weinberger A, Platt J, Copeland J, Goodwin R. Is cannabis use associated with increased risk of cigarette smoking initiation, persistence, and relapse? Longitudinal data from a representative sample of US adults. J Clin Psychiatry. 2018;79(2):17m11522.