UCSF

Background

Co-use of tobacco and cannabis has been associated with greater dependence on and lower quit rates for both substances. Tobacco/cannabis co-use among individuals with substance use disorders (SUDs), a population with high rates of cigarette smoking, may hinder the effectiveness of smoking cessation interventions. We examined rates of lifetime (i.e., ever vs. never) cannabis use among current cigarette smokers in SUD treatment, and we identified the subgroup who had used tobacco and cannabis together in the form of blunts and/or spliffs. We then examined variables associated with lifetime use of blunts and/or spliffs.

Methods

We surveyed 562 clients in 20 residential SUD treatment programs in California, USA, in 2019. Measures included demographics, lifetime use of any cannabis product, lifetime use of blunt/spliffs, patterns of tobacco use, and smoking cessation-related questions. We asked current cigarette smokers who also reported lifetime cannabis use whether they had ever used blunts and/or spliffs. We then assessed relationships of demographic, tobacco use, use of cannabis/tetrahydrocannabinol (THC) in e-cigarettes/vape pens, and smoking cessation-related variables with ever use versus never use of blunts/spliffs.

Results

Among 340 current cigarette smokers, 93.2% (n = 317) reported lifetime use of any cannabis product. Among current cigarette smokers with lifetime cannabis use, 64.4% reported lifetime blunt/spliff use. Compared to those who had never used blunts/spliffs, lifetime blunt/spliff users were more likely to be younger (OR = 0.93, 95% CI 0.90-0.95), more likely to report lifetime use of cigars/cigarillos (OR = 2.95, CI 1.37-6.32), and to have ever used cannabis/THC in e-cigarettes/vape pens (OR = 4.26, CI 1.54-11.80). They were less often ready to quit smoking within 30 days (OR = 0.37, CI 0.23-0.60), but more likely to want help with smoking cessation (OR = 2.39, CI 1.52-3.77).

Conclusion

Current cigarette smokers in SUD treatment reported a high prevalence of lifetime cannabis use. Smokers with a history of blunt/spliff use were more likely to report lifetime use of e-cigarettes/vape pens for cannabis/THC delivery. They wanted help to quit smoking, but felt less prepared to quit in the next 30 days. Cannabis co-use may warrant clinicians' attention when providing smoking cessation interventions during SUD treatment.