Colorado Teen Cannabis Use Falls Below Pre-Legalization Levels

Marijuana use among Colorado high school students has dropped to its lowest level in more than a decade — below where it stood before the state legalized adult-use cannabis — according to new results from a survey run by state health officials. The finding lands in the middle of a fight that has shaped cannabis ballot campaigns and statehouse debates for years: whether opening a legal market for adults pulls more teenagers into using the drug.

The Colorado data points the other way. The Healthy Kids Colorado Survey¹, a biennial poll administered by the Colorado Department of Public Health and Environment, found that 9.7 percent of high school students reported using marijuana in the past 30 days in 2025, down from 12.8 percent in 2023. The state’s health department said the decline has been significant over the past decade, with current youth use roughly halving from about 21 percent in 2015. The rate now sits below where it stood in 2011, the year before voters approved recreational legalization.

The argument the survey speaks to has been a fixture of cannabis politics. Opponents of adult-use measures, from organized campaigns to skeptical lawmakers, have long warned that legal storefronts would normalize the drug for minors and drive teen use up. Colorado, the first state to open recreational sales, has become the longest-running test of that prediction, which is why its youth data carries weight in legalization debates well beyond its borders.

Use and access both fell

The decline shows up across grade levels and across the questions the survey asks. Among middle schoolers in grades 6 through 8, past-30-day use fell to 1.5 percent in 2025, down from 3 percent two years earlier and 5.1 percent in 2013. Lifetime use, whether a student has ever tried cannabis, kept falling across grades 6 through 12.

Teenagers also reported that the drug is harder to find. In 2025, 33.5 percent of high school students said it would be “sort of easy or very easy” to get marijuana if they wanted it, down from 40.4 percent in 2023 and roughly 55 percent in 2013. Colorado’s current-use rate sits well under the national figure of about 17 percent that the U.S. Centers for Disease Control and Prevention reported in its most recent Youth Risk Behavior Survey. Those shifts in how teenagers view the drug track a broader change in teen cannabis perception that researchers have documented as more states moved away from prohibition.

The case for the regulated market

For legalization advocates and the state’s licensed industry, the survey is evidence that a regulated market does what prohibition could not: gate access by age. Licensed dispensaries must check identification and turn away anyone who can’t prove they are 21, a control that illicit dealers by definition don’t apply. Colorado’s Marijuana Enforcement Division reported in March 2026 that licensed retailers deny entry roughly 99 percent of the time to would-be customers without valid proof of age.

“These findings are consistent with those from other adult-use legal states, which show steep declines in marijuana use by young people following the adoption of regulated, age-restricted markets,” said Paul Armentano, deputy director of NORML, of the Colorado results.

The industry group Colorado Leads made a similar case, framing the numbers as proof that the framework voters adopted with Amendment 64 in 2012 is working as designed. The survey also found that disapproval among teens has climbed, with nearly 80 percent of respondents saying it is wrong for someone their age to use cannabis. Supporters point to the state’s billions in cannabis tax revenue as the other half of a bargain that legalization campaigns in other states routinely cite.

Colorado is not alone in the pattern. State surveys have shown adolescent use dropping even as legal access expanded, and a growing body of research has reported teen substance use falling in states that legalized cannabis for adults. Federal survey data has likewise put adolescent marijuana use at or near historic lows nationally.

What the numbers don’t settle

The survey is self-reported, and critics have long questioned whether teenagers answer candidly about illegal behavior. Some Colorado advocates worried about commercialization point to other measures — school disciplinary incidents and emergency-room visits tied to high-potency concentrates — that they say complicate the optimistic read. The Healthy Kids survey also doesn’t track how often heavy users consume or the potency of the products teens encounter, both of which have shifted sharply since retail sales began in 2014.

State officials offered their own caution, saying the long-term trends are encouraging but that holding them depends on continued prevention work. What the data undercuts, advocates argue, is the prediction that legalizing cannabis for adults would push more minors toward it — a forecast Colorado’s decade of survey results has not borne out.

References:

^{1. Colorado Department of Public Health and Environment, “Healthy Kids Colorado Survey” (2025). https://cdphe.colorado.gov/hkcs}