E-cigarette and cannabis use among current and recently quit smokers: Co-use and Co-cessation.

Background: Concurrent use of cigarettes with e-cigarette or cannabis (co-use) is common. It is unclear whether people who want to quit smoking cigarettes would also be interested in quitting using e-cigarettes/cannabis (co-cessation). Methods: In a survey of 391 Californian adults, participants reported past 30-day use of and intentions to quit cigarettes, e-cigarettes, and cannabis, and reasons for using e-cigarettes and/or cannabis. Using cross-tabulation tables, we examined the relationship between cigarette, e-cigarette, and cannabis cessation intentions. We subsequently examined how the reasons for using e-cigarettes and cannabis related to e-cigarette and cannabis use frequency, while controlling for cigarette use and demographic characteristics. Results: Of those who used both cigarettes and e-cigarettes and planned to quit smoking within the next 30 days, 68.9 % also planned to quit using e-cigarettes. Of those who used both cigarettes and cannabis and intended to quit smoking within 30 days, 30.0 % also wanted to quit using cannabis within the same period. Using e-cigarettes or cannabis to aid with cigarette cessation had no impact on e-cigarette or cannabis use frequency. Significance: Those who intended to quit smoking cigarettes within 30-days also expressed interest in quitting e-cigarettes or cannabis within the same period. Using e-cigarettes or cannabis to quit smoking was not related to higher frequency e-cigarette or cannabis use. Future interventions may promote co-cessation of cigarettes, e-cigarettes, and cannabis simultaneously.