A new study published on May 9 in the Journal of Adolescent Health shows evidence that cannabis legalization has brought down the consumption of alcohol and cigarettes in youth consumers. Entitled “Trends in Alcohol, Cigarette, E-Cigarette, and Nonprescribed Pain Reliever Use Among Young Adults in Washington State After Legalization of Nonmedical Cannabis,” the study includes the analysis of six waves of survey data collected between 2014 and 2019. Researchers from the University of Washington reviewed data which covered approximately 12,500 adolescents.

“Prevalence of past-month alcohol use, heavy episodic drinking (HED), and cigarette use and prevalence of past-year pain reliever misuse decreased, while the prevalence of past-month e-cigarette use increased since 2016 (the first year assessed),” researchers wrote about the results. “Across years and age groups, the prevalence of substance use other than cannabis was higher among occasional and frequent cannabis users compared to cannabis nonusers.”

As the years continued and more states began working on legalization programs, many of these consumption habits began to decrease over time. “However, associations between both occasional (1–19 days in the prior month) and frequent (20+ days) cannabis use and pain reliever misuse and between frequent cannabis use and HED weakened over time among individuals ages 21–25.”

“Contrary to concerns about spillover effects, implementation of legalized nonmedical cannabis coincided with decreases in alcohol and cigarette use and pain reliever misuse,” researchers concluded.

However, it is commonly recommended that more studies be conducted to better understand the effects of legalization on youth consumption. “The weakening association of cannabis use with the use of other substances among individuals ages 21–25 requires further research but may suggest increased importance of cannabis-specific prevention and treatment efforts,” researchers wrote.

Many other studies have evaluated the influence of cannabis on young adults from a variety of perspectives. A study published earlier this week questioned the effect of cannabis being portrayed positively on TikTok as a concern for the youth who frequently use the app.

In March 2022, a policy paper released by the Coalition for Cannabis Policy, Education and Regulation (CPEAR) analyzed youth cannabis consumption as well, and also reported that youth cannabis consumption hasn’t increased since legalization began. Results claim that continued work in creating a federal framework to help curb cannabis misuse by youth in the U.S. is essential and recommended a focus on eliminating access to illegal cannabis in the process.

In March 2021, another study was published, with an analysis of 46 states and data collected between 1991-2015. “This study found no evidence between 1991 and 2015 of increases in adolescents reporting past 30-day marijuana use or heavy marijuana use associated with state MML (medical marijuana law) enactment or operational MML dispensaries,” the authors wrote in their abstract.

Back in 2020, yet another study explored the effects of legalization, and found that there was little impact on youth specifically in California. “Contrary to the claims of many legalization opponents, changes in states’ marijuana policies have not led to any significant rise in cannabis use among young people,” NORML Deputy Director Paul Armentano said about the study. “Overall, most voters believe that these adult-use policies are operating as intended, which is why no state that has legalized the use of cannabis for either medical or adult-use purposes has ever repealed their law.”

These studies go back to the earlier years of adult-use legalization, as seen in published findings from 2016 from the Colorado Health Department who found teens saying that four out of five high school students “say they don’t use marijuana, even occasionally.”

While these studies help show that youth cannabis consumption has not increased, there is still the question of how cannabis consumption affects young adults’ minds. Some studies claim that cigarettes cause the decline of grades more than cannabis does, according to a 2016 study. However, in 2018 a study found evidence that kid’s cognitive development can be affected, followed by another study in 2019 that found no link between adolescent cannabis consumption and adult brain structure. Due to the conflicting information, more studies are necessary in order to learn more about how cannabis affects adolescents.