cannabis legalization correlates with falling teen cannabis use in Colorado, according to the 2025 Healthy Kids Colorado Survey (HKCS) released by the Colorado Department of Public Health and Environment (CDPHE). The survey found that 9.7% of Colorado high school students reported using marijuana in the past 30 days in 2025, down from 12.8% in 2023.
The HKCS results show a long-term decline in youth cannabis use since before legalization. CDPHE data indicate a 56% decrease in current (past-30 day) marijuana use among high school students compared with 2011, the year before Colorado voters approved adult-use legalization. Colorado’s 9.7% past-month rate also sits below the U.S. Centers for Disease Control and Prevention Youth Risk Behavior Survey national average of 17% for high school students.
Middle school results follow the same pattern. Just 1.5% of students in grades 6–8 reported past-30 day cannabis use in 2025, down from 3% in 2023 and 5.1% in 2013. Lifetime use among students in grades 6–12 has also fallen, the HKCS reports.
Perceived access to marijuana has decreased as well. In 2025, 33.5% of youth said it would be “sort of easy or very easy” to obtain marijuana if they wanted it, a 39% drop from that measure in 2013. CDPHE highlighted these trends as evidence that youth exposure and reported access have declined over the past decade.
Industry and reform advocates point to regulation and age checks as contributing factors. Chuck Smith, CEO of Colorado Leads, said the industry is pleased by the trend and credited consistent age-verification compliance and regulatory controls at licensed retailers for reducing underage access. NORML Deputy Director Paul Armentano noted the Colorado findings match patterns seen in other adult-use states, where youth use has fallen after legalization and the introduction of regulated markets.
Independent and government studies offer similar results. A Marijuana Policy Project analysis found youth marijuana use declined in 19 of 21 states that legalized adult-use cannabis, with an average drop of about 35% in the earliest-legalized states. A U.S. study covering 2011–2021 reported decreases in both lifetime and past-month use among high school students nationwide over that decade. JAMA-published analyses in 2024 also concluded that legalization laws and retail openings have not increased youth cannabis use.
Outside the U.S., recent reports from Canada and Germany found youth use did not rise following national or broad legalization. Minnesota’s post-legalization data likewise show middle and high school cannabis use at or near record lows for the past decade.
Federal health data reflect a related pattern: increases in past-year marijuana use in recent years have been concentrated among adults aged 26 and older, while rates for adolescents and young adults remained stable between 2021 and 2024.
What the data show is correlation rather than proven causation. Researchers and public health officials caution that multiple factors can affect youth substance use trends, including prevention programs, changing social norms, enforcement practices, and product availability. Still, the consistency of declines across several jurisdictions suggests that regulated adult-use markets—where retailers must check IDs, test products, and follow tracking requirements—are one plausible mechanism reducing youth access compared with unregulated illicit markets.
Policy implications
Colorado’s HKCS offers measurable benchmarks policymakers can use to assess how regulation affects youth. Concrete figures from the survey include: – High school past-30 day use: 9.7% (2025) vs. 12.8% (2023) – Middle school past-30 day use (grades 6–8): 1.5% (2025) vs. 3% (2023) – Perceived ease of access among youth: 33.5% (2025), a 39% drop since 2013 – National comparison: Colorado high school rate 9.7% vs. CDC national average 17%
Enforcement and compliance remain central. State officials and industry representatives point to ongoing age-verification checks and refusal-of-sale rates as measurable enforcement outcomes. CDPHE officials said they will continue monitoring trends and working with schools, law enforcement, and the regulated sector to sustain declines in youth use.
Researchers recommend continued, regular surveys to track changes, targeted prevention programs for at-risk populations, and enforcement measures that focus on illegal diversion channels. Trials of different prevention strategies, combined with consistent data collection, will allow states to test which approaches most effectively lower youth use.
Bottom line
Colorado’s 2025 HKCS shows lower self-reported cannabis use and reduced perceived access among youth compared with recent years and with national averages. Multiple studies across U.S. states and other countries report similar patterns after legalization, and public health officials continue to monitor the data to guide enforcement and prevention efforts. The available evidence indicates regulated adult markets, combined with age checks and compliance enforcement, are associated with declines in youth cannabis use in Colorado and several other jurisdictions.
