REVIEW OF: Weinberger AH et al, J Clin Psychiatry 2018;79(2):17m11522

When counseling your patients to quit smoking, you may also want to consider asking them about their past marijuana use. Results from a recent study suggest that there may be a correlation between cannabis and tobacco smoking.

Analysis of longitudinal data of almost 35,000 adult study participants, gathered during two “waves” (2001–2002 and 2004–2005) of the U.S. National Epidemiologic Survey on Alcohol and Related Conditions, found that past cannabis use was associated with an increase in cigarette smoking initiation, persistence, and relapse.

In the study, cannabis use was associated with a 2.9-fold and 4.4-fold increased risk of new cigarette use on either a daily or non-daily basis, respectively, compared to those without exposure to cannabis in the previous year.

Among former smokers, past cannabis use was associated with increased relapse rate: 4.18 times more ex-smokers returned to daily smoking and 5.24 times more ex-smokers returned to smoking on a non-daily basis compared to those who had not used cannabinoids in the past 12 months.

Past cannabis use was also associated with difficulty quitting tobacco: Among daily cigarette smokers, past cannabinoid use was associated with decreased odds of smoking cessation by 43% compared with non-cannabis users. Even when demographics and a history of psychiatric disorders were taken into consideration, associations of cannabis use remained significant for the initiation of daily smoking among prior nonsmokers; relapsing to a daily use pattern among former ex-smokers; and difficulty quitting among daily smokers.

CATR’s Take
This study provides some interesting data showing that people who use cannabis are more likely to also smoke tobacco. Tell your patients that if they’ve used cannabis in the past, quitting tobacco may be more of a challenge than usual. This will set the stage for a discussion of the various smoking cessation agents available, and it might increase your patients’ motivation to accept treatment.