Young Adults Reported Fewer Alcohol and Cigarette-Use Days After California Cannabis Legalization
A 2023 study of cannabis-using 18- to 20-year-olds in Los Angeles found that participants surveyed after California’s adult-use cannabis policy took effect reported fewer days of alcohol and cigarette use than a comparable group surveyed before legalization. The study also found greater use of cannabis edibles, while the overall frequency of cannabis use did not significantly change.
The research, published in the Journal of Psychoactive Drugs, compared two groups recruited through the Cannabis, Health and Young Adults study. The pre-legalization cohort included 172 participants surveyed from February 2014 through February 2015. The post-legalization cohort included 139 participants surveyed from June 2019 through August 2020.
California legalized adult-use cannabis in 2016, with retail sales beginning in 2018. People younger than 21 remained ineligible to purchase cannabis for adult use, although those 18 and older could obtain it with a physician’s recommendation. The state’s Department of Cannabis Control explains the distinction between medicinal and adult-use access.
All participants in the study were already active cannabis users, defined as using cannabis at least four times during the previous month. That means the findings do not show whether legalization increased or decreased cannabis use across all young adults. Instead, they describe changes in patterns of use among young cannabis users in the Los Angeles area.
After researchers adjusted for demographic differences and medical-cannabis status, the post-legalization group reported significantly fewer days of alcohol and cigarette use. Participants in that group were also more likely to report using edibles. However, measures of cannabis frequency—including the number of days used and hits per day—generally did not differ between the two cohorts.
The pattern is consistent with what researchers call a possible substitution effect: some participants may have used cannabis in place of alcohol or cigarettes. But the study cannot establish that cannabis legalization caused the decline. It used two separate, nonrandom samples rather than following the same individuals over time, and other changes between 2014–15 and 2019–20 could have influenced substance use. The final portion of the post-legalization interviews also took place during the COVID-19 pandemic.
The researchers found no significant cohort differences in reported illicit-drug use or prescription-drug misuse. They suggested that future studies should track whether the lower alcohol and cigarette-use levels persist as participants reach 21, when they become legally eligible to purchase alcohol, tobacco, and adult-use cannabis. Longer follow-up could also clarify whether the shift toward edibles has implications for cannabis-related risks.
Overall, the study offers limited but notable evidence that adult-use legalization was associated with fewer reported alcohol- and cigarette-use days among young cannabis users in Los Angeles. It does not demonstrate a protective effect, prove that cannabis replaced those substances, or establish that the same pattern occurs among young adults elsewhere.
