Current cannabis use and smoking cessation among treatment seeking combustible smokers.

INTRODUCTION: Combustible tobacco smoking and cannabis use frequently occur together, and the use of both substances is associated with overall greater severity of tobacco and cannabis related problems. Observational work has found that cannabis use is associated with tobacco cessation failure, but research directly testing the longitudinal associations of cannabis use on tobacco cessation during smoking cessation treatment is lacking. The current study examined the impact of current cannabis use on combustible tobacco cessation outcomes. METHODS: 207 daily combustible tobacco smokers (Mage = 38.24 years, SD = 14.84, 48.1 % male) were enrolled in a randomized controlled smoking cessation trial. Survival analyses and multi-level modeling were used to assess lapse and relapse behavior through 12-week follow up. The current study is a secondary data analysis. RESULTS: Results of the current study suggest that cannabis use is associated with faster time to lapse (OR = 0.644, se = .188, p = .019), but not relapse (OR = -0.218, se = .403, p = .525), compared to combustible tobacco-only smokers. Additionally, cannabis use was associated with lower likelihood of achieving any 7-day point prevalence abstinence during the 12 week follow up (b = 0.93, se = 0 0.24, p = 0.0001). CONCLUSIONS: The current study provides novel evidence that cannabis use may be related to combustible tobacco use in terms of faster time to lapse and lower likelihood of any 7-day point prevalence abstinence following smoking cessation treatment. Developing integrated cannabis-tobacco cessation treatments is an important next step in research focused on tobacco-cannabis use.