People Who Think Secondhand Cannabis Smoke Is Harmful Are Less Likely to Smoke at Home

Those at the 75th percentile (vs 25th) of perceived harm from secondhand cannabis smoke had 70% higher odds (OR=1.7) of reporting no in-home cannabis smoking. The association held across all 21 countries, with the strongest effects in Sweden (OR=3.9) and New Zealand (OR=2.3). Mean perceived harm was 5.2 on a 10-point scale. 61% reported no in-home cannabis smoking.

Cross-sectional analysis of 28,154 adult respondents from 21 countries in the 2021 Global Drug Survey. Logistic regression adjusted for covariates estimated the association between perceived harm of secondhand cannabis smoke exposure and reporting no in-home cannabis smoking in the past 30 days.

As cannabis legalization expands, most smoking occurs at home, exposing household members to secondhand smoke. If harm perception drives behavior change, public health campaigns emphasizing secondhand cannabis smoke risks could reduce residential exposure.

The parallel to tobacco secondhand smoke messaging is clear. Decades of public health campaigns shifted norms around indoor tobacco smoking. This study suggests similar messaging about cannabis could be effective, particularly as legalization removes the stigma that previously kept use out of the home.

Cross-sectional design cannot prove harm perception causes behavior change; people who do not smoke at home may simply rationalize it as being about harm. Convenience sample of Global Drug Survey respondents may not represent general cannabis users. Self-reported in-home smoking may be subject to social desirability bias.