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

Background: 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.Objectives: 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.Methods: 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 (n = 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.Results: The exclusive use of cannabis through ingestion methods increased from 4.0% in 2017 to 16.6% in 2022 (p < .001). However, the exclusive use of inhalation-based cannabis decreased from 49.4% in 2017 to 25.5% in 2022 (p < .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.Conclusions: 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.