Marijuana use among Minnesota adolescents fell substantially between 2013 and 2025, declining across every demographic group examined even as the state adopted increasingly permissive marijuana laws during that period, according to a new study.
Published by Social Science & Medicine, the study was conducted by researchers from the University of Minnesota, University of Connecticut and Hennepin Healthcare Research Institute.
Researchers found that the share of ninth- and 11th-grade students reporting marijuana use within the past 30 days declined from 12.7% in 2013 to 5% in 2025, a decrease of more than 60%.
“The prevalence of any past 30-day cannabis use declined from 2013 to 2025 for the full sample,” the researchers wrote, adding that “this downward trend was evident for all subgroups examined.”
The study used data from the 2013, 2016, 2019, 2022 and 2025 Minnesota Student Survey. Depending on the year, between 45,180 and 75,551 students participated.
Researchers compared marijuana use according to students’ sex assigned at birth, sexual orientation, gender identity, racial and ethnic identity and experiences with poverty. They also examined whether disparities between historically marginalized and more privileged groups had widened or narrowed over the 12-year period.
The decline occurred as Minnesota gradually loosened its marijuana laws. The state legalized medical marijuana in 2014, authorized certain hemp-derived THC products for adults in 2022 and legalized recreational marijuana for those 21 and older in 2023.
The researchers noted that legalization has prompted concerns that greater availability, declining perceptions of harm and the normalization of adult marijuana use could increase consumption among adolescents. However, the study’s findings were consistent with broader research showing that youth marijuana use has generally declined or remained unchanged as adult-use legalization has expanded.
“Rates of cannabis use have been declining over the past twelve years among adolescents, in spite of increasingly liberal policies and attitudes around use over this same time period,” the researchers wrote.
The study’s primary contribution was its ability to determine whether the overall decline was shared across a wide range of social identities. Previous research has often lacked a sufficiently large sample to separately examine smaller racial, sexual-orientation and gender-identity groups.
Although marijuana use declined in every group studied, marginalized students generally remained more likely to report recent use than their more privileged counterparts. Still, disparities narrowed significantly for numerous groups, particularly across racial and ethnic identities.
The researchers said disparities associated with sexual orientation and gender identity were generally similar in 2025 to those recorded in 2013.
The authors had hypothesized that marginalized youth would experience smaller reductions, causing disparities to widen. Instead, the downward trend was broadly shared, and marijuana use among some marginalized groups declined more sharply.
The study did not determine precisely why adolescent marijuana use has fallen. Researchers pointed to possible explanations identified in earlier research, including increased parental monitoring, less unstructured in-person socializing, more time spent using screens and broader declines in adolescent risk-taking behaviors.
Despite the overall improvement, the researchers said substantial disparities remain for certain groups and recommended that prevention programs focus on reducing stigma and addressing the pressures experienced by marginalized youth.
“Health equity should be the focus of ongoing cannabis use prevention efforts,” the researchers concluded, “particularly reducing stigma, which previous research has shown to be a substantial contributor to cannabis use disparities.”
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