Changes in adult cannabis use patterns following retail availability in California (2017 to 2024)

California was among the earliest U.S. states to legalize non-medical cannabis use by adults, with retail availability beginning January 1, 2018. This study describes changes in cannabis use prevalence, frequency, and methods among adults in California from 2017 through 2024, spanning the year before and seven years after the onset of retail availability.

Data were drawn from 178,836 adults aged ≥18 years in the California Health Interview Survey (2017-2024). Survey-weighted logistic regression models with year as a categorical predictor were used to estimate year-specific prevalence, with Tukey adjustment for pairwise comparisons. All analyses accounted for survey weights, strata, and primary sampling units.

Past-year and past-month cannabis use were reported by 24.7% (95% CI: 24.3-25.0) and 16.4% (95% CI: 16.1-16.8) of respondents, respectively. Past-year use was 22.1% (95% CI: 20.9-23.2) in 2017 and 23.5% (95% CI: 22.8-24.2) in 2024 (p =  0.24). Past-month use rose from 14.5% (95% CI: 13.5-15.5) in 2017 to 17.7% (95% CI: 16.6-18.8) in 2018 (p < 0.01), then fell to 15.4% (95% CI: 14.8-16.0) in 2024, which did not differ significantly from 2017 (p =  0.65). Frequency of use was concentrated at the ends of the distribution (1-5 days/month: 40%; 20-30 days/month: 37.3%), with no statistically significant differences across years. Combustible methods (joints, pipes, or bongs) declined from 71.2% (95% CI: 69.2-73.2) to 58.1% (95% CI: 55.8-60.4) (p < 0.01), while edible use rose from 40.3% (95% CI: 37.4-43.2) to 53.6% (95% CI: 51.4-55.8) (p < 0.01). From 2017 to 2024, past-month use increased among adults aged 40-59 years from 10.7% (95% CI: 9.5-12.1) to 14.5% (95% CI: 13.5-15.6) and among adults ≥75 years from 2.4% (95% CI: 1.5-3.9) to 5.5% (95% CI: 4.6-6.4) (both p < 0.01).

Prevalence of past-year and past-month cannabis use among adults in California remained largely stable across the eight-year study period spanning the onset of retail availability of non-medical cannabis products. Frequency of past-month use also remained stable. Methods of use shifted notably, however, with declines in combustible methods and corresponding increases in edible consumption. Past-month use increased among middle-aged and older adults, particularly those aged ≥75 years, while remaining unchanged among young adults (18-25 years).