Most Cannabis Users Worldwide Smoke at Home, Exposing Others to Secondhand Smoke

Among international cannabis users, any in-home smoking was reported by 63.9% of men, 61.9% of women, and 68.6% of nonbinary people. Daily in-home smoking was highest among nonbinary respondents (28.7%) and those 35+ years old (28.0%). US-specific weighted estimates showed any in-home smoking at 49.8% for males and 61.2% for females, with daily rates of 23.2% and 37.1% respectively.

Cross-sectional analysis of 63,797 international cannabis users from the 2020 Global Drug Survey (Nov 2019-Jan 2020). US respondents (n=6,580) were weighted to the nationally representative NSDUH cannabis-using population using inverse odds probability weighting.

In-home cannabis smoking exposes household members to secondhand and thirdhand smoke. With the number of cannabis users increasing due to legalization, and criminal stigma driving use indoors, residential exposure is a growing public health concern.

The paradox of legalization is that while it reduces the stigma of cannabis use, it may increase residential exposure because users feel more comfortable smoking at home. Criminal stigma has historically driven users indoors; legal stigma may be replaced by social norming of home use.

Global Drug Survey is a convenience sample that overrepresents engaged drug users. Self-reported in-home smoking may underestimate actual behavior. Weighting corrects for some selection bias in US data but cannot fully address it.