Changes in modes of cannabis consumption pre- and post-legalization and their correlates among adults in Ontario, Canada: 2017-2022.

Despite an increase in the varieties of cannabis products available for consumption, limited evidence is available about the patterns of cannabis consumption methods before and after legalization. To examine the changes in modes of cannabis use and their correlates among adults in Ontario, Canada both prior to and following cannabis legalization in 2018. Data were utilized from the 2017 to 2022 Centre for Addiction and Mental Health's (CAMH) Monitor study, a repeated cross-sectional survey of adults 18 years of age and older ( = 2,665; 56% male). The surveys employed a regionally stratified sampling design using computer-assisted telephone interviews and web surveys. Multinomial regression was performed to examine different modes of cannabis use. The exclusive use of cannabis through ingestion methods increased from 4.0% in 2017 to 16.6% in 2022 ( < .001). However, the exclusive use of inhalation-based cannabis decreased from 49.4% in 2017 to 25.5% in 2022 ( < .001). Relative to inhalation-based modes, adults were about five times more likely to use ingestion-based modes in 2020 [RRR = 4.65 (2.94-7.35)] and 2022 [RRR = 4.75 (2.99-7.55)] than in 2019, after accounting for sociodemographic factors. Ingestion-based cannabis use among adults increased fourfold between 2017 and 2022, a period during which recreational cannabis use was legalized in Canada. The increase was especially evident after the legalization of cannabis edibles.