Recreational Marijuana Legalization and Use Among
California Adolescents: Findings From a Statewide Survey

a & JOEL W. GRUBE, Ph.d.a

Prevention Research Center, Pacific Institute for Research and Evaluation, Berkeley, California

Conclusions: RML in California was associated with an increase in adolescent marijuana use in 2017–2018 and 2018–2019. Demographic subgroup differences in these associations were observed.

Youth use increased in legalized states as compared to states without legal recreational marijuana

Our MissiAssociation Between Recreational Marijuana Legalization in the United States and Changes in Marijuana Use and Cannabis Use Disorder From 2008 to 2016on


How did marijuana use and cannabis use disorder change during 2008 to 2016 after the legalization of recreational marijuana in the United States?


In this multilevel, difference-in-difference survey study with 505 796 respondents comparing marijuana use before and after the legalization of recreational marijuana in the United States, the proportion of respondents aged 12 to 17 years reporting cannabis use disorder increased from 2.18% to 2.72%, while the proportion of respondents 26 years or older reporting frequent marijuana use increased from 2.13% to 2.62% and those with cannabis use disorder, from 0.90% to 1.23%.


This study’s findings suggest that possible increases in the risk for cannabis use disorder among adolescent users and increases in frequent use and cannabis use disorder among adults after legalization of recreational marijuana use may raise public health concerns and warrant ongoing study.

Youth being more likely to use potent products in legalized states 

Background—Alternative methods for consuming cannabis (e.g., vaping and edibles) have
become more popular in the wake of U.S. cannabis legalization. Specific provisions of legal
cannabis laws (LCL) (e.g., dispensary regulations) may impact the likelihood that youth will use
alternative methods and the age at which they first try the method – potentially magnifying or
mitigating the developmental harms of cannabis use.
Methods—This study examined associations between LCL provisions and how youth consume
cannabis. An online cannabis use survey was distributed using Facebook advertising, and data
were collected from 2630 cannabis-using youth (ages 14–18). U.S. states were coded for LCL
status and various LCL provisions. Regression analyses tested associations among lifetime use and
age of onset of cannabis vaping and edibles and LCL provisions.
Results—Longer LCL duration (ORvaping: 2.82, 95% CI: 2.24, 3.55; ORedibles: 3.82, 95% CI:
2.96, 4.94), and higher dispensary density (ORvaping: 2.68, 95% CI: 2.12, 3.38; ORedibles: 3.31,

The use of more potent products is associated with greater risk of addiction (and if addicted, escaping the mental health consequences becomes obviously more difficult)

Changes in cannabis potency and first-time admissions to drug treatment: a 16-year study in the Netherlands

Conclusions: In this 16-year observational study, we found positive time-dependent associations between changes in cannabis potency and first-time cannabis admissions to drug treatment. These associations are biologically plausible, but their strength after adjustment suggests that other factors are also important.

Youth Use

Marijuaan use among young people in “legal” states is alarmingly high.