Cannabis co-use patterns among cigarette smokers varied by country, with higher rates in Canada and the US | Research

The takeaway

Among 10,035 cigarette smokers across four countries, Canada had the highest rate of cannabis co-use (36%), followed by the US (29%), England (22%), and Australia (21%), with co-users in the US and Canada more likely to perceive cannabis as less harmful than cigarettes.

Tobacco and cannabis policy makers, public health researchers, and smoking cessation specialists.

90% of English co-users mixed tobacco with cannabis vs 22% in the US

What the researchers found

Countries with more permissive cannabis regulations (Canada, US) had higher co-use rates and daily cannabis use among co-users. Co-users in England (90%) and Australia (86%) were far more likely to mix tobacco with cannabis than those in Canada (39%) or the US (22%).

Why it matters

The dramatic differences in co-use patterns between countries suggest that cannabis regulation shapes not just use rates but also how cannabis is consumed, with implications for both cannabis and tobacco policy.

The numbers in context

Co-use rates: Canada 36.3%, US 29.1%, England 21.6%, Australia 21.4%. Daily cannabis use among co-users: US 40.2%, Canada 35.2%, England 26.3%, Australia 21.7%. Tobacco-cannabis mixing: England 90.4%, Australia 86.0%, Canada 38.5%, US 22.3%.

How the study worked

Cross-sectional data from the 2018 International Tobacco Control 4-Country Vaping Survey. 10,035 adult cigarette smokers from Canada, US, Australia, and England were surveyed about cannabis use patterns and perceptions.

What this study cannot tell us

Cross-sectional design at one time point. Only cigarette smokers were included, not the general population. Self-reported data. Different cultural and regulatory contexts make direct comparisons complex.

How to read the evidence

Strong: large multinational survey with standardized methodology across four countries.

When this study was published

Published in 2020 in International Journal of Drug Policy.

The bigger picture

The high rates of tobacco-cannabis mixing in England and Australia create a unique public health challenge where cannabis use directly reinforces nicotine addiction, a pattern much less common in North America.

Questions still open

Does cannabis legalization increase co-use with tobacco? Would reducing tobacco-cannabis mixing in Europe/Australia improve smoking cessation outcomes? How has Canadian legalization (2018) affected these patterns since the survey?

Common questions

Why do Europeans mix tobacco with cannabis more?

Cultural norms around cannabis consumption differ significantly. In England and Australia, the tradition of mixing tobacco with cannabis in "spliffs" is dominant, while North American users more commonly consume cannabis without tobacco.

Does legal cannabis lead to more tobacco-cannabis co-use?

The data suggest countries with more permissive cannabis laws have higher co-use rates, but they also have lower tobacco-cannabis mixing rates. The relationship between regulation and co-use patterns is complex and influenced by cultural factors.

Read the original research

International differences in patterns of cannabis use among adult cigarette smokers: Findings from the 2018 ITC Four Country Smoking and Vaping Survey.

The International journal on drug policy, 79, 102754

View on PubMed ↗Publisher’s paper ↗

Citation

Gravely, Shannon; Driezen, Pete; Smith, Danielle M; Borland, Ron; Lindblom, Eric N; Hammond, David; McNeill, Ann; Hyland, Andrew; Cummings, K Michael; Chan, Gary; Thompson, Mary E; Boudreau, Christian; Martin, Nadia; Ouimet, Janine; Loewen, Ruth; Quah, Anne C K; Goniewicz, Maciej L; Thrasher, James F; Fong, Geoffrey T. (2020). International differences in patterns of cannabis use among adult cigarette smokers: Findings from the 2018 ITC Four Country Smoking and Vaping Survey.. The International journal on drug policy, 79, 102754. https://doi.org/10.1016/j.drugpo.2020.102754