Research

Teen cannabis use keeps falling — even in legal states

Monitoring the Future — the federal government's 50-year running survey of American adolescent substance use — shows teen cannabis use down 23-45% since 2012, even as 26 states legalized adult-use. The 1999 peak predates any recreational legalization. The foundational prohibition argument that legalization would produce a teen use crisis has been empirically disconfirmed by the government's own data.

The Green Brief·April 18, 2026·8 min read

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For decades, the loudest argument against cannabis legalization has been that it would increase teen use. Advocacy groups warned that retail availability, advertising, and normalization would pull more young people into marijuana consumption. Federal agencies held this concern up as a defining reason to keep cannabis in Schedule I.

Twenty-six states and the District of Columbia later have legalized adult-use cannabis. And what the data actually shows — from the federal government's own survey, tracked continuously since 1975 — is the opposite of what the prohibition argument predicted.

Teen cannabis use in the United States is at or near its lowest point in recorded history. And the decline has accelerated in the states that legalized earliest.

What Monitoring the Future actually shows

Monitoring the Future (MTF) is the longest-running federal survey of American adolescent substance use. Funded by the National Institute on Drug Abuse and conducted by the University of Michigan, MTF surveys roughly 40,000 8th, 10th, and 12th graders annually across hundreds of schools. It is the gold-standard data source for teen substance use trends.

The most recent available MTF data — the 2025 survey, released in early 2026 — shows the fifth consecutive year of teen substance use holding at or near historic lows across nearly every measured category, including cannabis.

Long-term decline in adolescent cannabis use (1991 baseline → 2025):

12th graders: lifetime use down approximately 23% since 2012, past-month use down approximately 25%
10th graders: lifetime use down approximately 35% since 2012, past-month use down approximately 45%
8th graders: lifetime use down approximately 17% since 2012, past-month use down approximately 38%

The 10th grade numbers are particularly striking: a 45% decline in current cannabis use among 15- and 16-year-olds since 2012, during the exact period when two dozen states legalized adult-use cannabis.

The peak was 1999

Teen cannabis use in the United States peaked in 1999, when 47.3% of 12th graders reported having ever used cannabis. This predates recreational legalization in any U.S. jurisdiction by 13 years. The 1999 peak was the end product of 1990s-era normalization, the rise of hip-hop cannabis culture, and relatively permissive parental attitudes carrying over from the 1970s and 1980s.

By 2023, that number had fallen to 30.1%. By 2025, MTF showed continued declines.

The peak and the subsequent decline both happened under federal prohibition. The decline accelerated under state-level legalization. The two observations, taken together, point to a conclusion the prohibition advocacy community has been slow to accept: federal cannabis policy is not the primary determinant of teen cannabis use. State-level retail access is not the primary determinant. The primary determinants are, best as can be measured, cultural, parental, and peer-based.

The counterintuitive legalization finding

The most methodologically important finding in teen cannabis research is this: states that have legalized adult-use cannabis have not seen increases in teen use, and several have seen measurable decreases.

Multiple studies have examined this question using MTF data, state-level substance use surveys, and comparative analyses. The findings are consistent:

Colorado and Washington (early legalizers, 2012) — teen use flat or declining post-legalization
California (legalized 2016) — teen use declined post-legalization
Massachusetts (legalized 2016) — teen use declined
New York (legalized 2021) — early data shows continued decline, though long-term measurement is pending

The mechanism is not fully understood, but the leading hypotheses include:

Regulated retail displaces illicit markets that were previously more accessible to minors (dispensaries check IDs; dealers do not)
Legalization reduces the "forbidden fruit" effect that contributed to adolescent experimentation
Age restrictions and public health messaging have been more successful in legal markets than they were under prohibition
Cultural normalization of adult cannabis use may paradoxically reduce adolescent appeal

The evidence on mechanism is preliminary. The evidence on outcome — teen use has not increased — is now consistent enough across jurisdictions and study designs to be treated as a robust finding.

The gender crossover

One significant shift MTF has documented is a gender crossover that occurred around 2021. For most of MTF's 50-year history, teen boys consistently reported higher cannabis use than teen girls. Starting in 2021, girls surpassed boys in reported marijuana use — a reversal that has held in subsequent years.

The cause is not fully understood. Possible contributing factors include:

Differential impact of social media and mental health trends, which have hit adolescent girls harder in the post-2015 period
Changing peer dynamics around cannabis framing (wellness vs. rebellion)
Methodological considerations in self-reporting

The crossover is consequential for public health programming, which has historically been calibrated toward male adolescent risk patterns.

What the data does not support

Several claims made in anti-legalization advocacy have not survived contact with the data:

Claim: Legalization will increase teen cannabis use. Evidence: Teen use has held flat or decreased in every state that has legalized.

Claim: Retail availability drives adolescent consumption. Evidence: Dispensaries appear to be more effective at age-gating than illicit markets they replaced.

Claim: Cannabis advertising normalizes use for minors. Evidence: While advertising has expanded, measurable teen use has declined — the normalization-to-consumption pipeline does not appear to function as predicted.

Claim: "Today's weed" (higher-potency cannabis) is producing measurably more adolescent harm. Evidence: This is a serious concern for the subset of teens who do use heavily; it is not evidence that aggregate teen use or aggregate harm has increased in legalized states.

The distinction between prevalence (how many teens use) and intensity (how heavily do those who use consume) matters here. Prevalence is declining across MTF measures. Intensity, particularly regarding high-THC concentrate use, remains an active area of research with more concerning findings. Both observations can be true simultaneously.

The policy implication

The Monitoring the Future data does not prove legalization is safe for teens. It demonstrates that the specific predicted harm — increased teen prevalence — has not materialized under a decade of accumulated state-level experimentation.

For federal policymakers, this has significant implications:

The DEA's rescheduling proposal — now in procedural limbo — is based in part on HHS's 2023 finding that cannabis has accepted medical use. The "protect the children" argument against rescheduling is substantially weaker when the data shows no adolescent harm from state-level legalization.
Congressional opposition to rescheduling, grounded in teen-use concerns, increasingly runs against the empirical record.
State-level legalization campaigns now have a decade of data demonstrating that the predicted teen use increase has not occurred.

None of this resolves the public health questions that remain — particularly around high-potency concentrate use, adolescent mental health correlates, and the driving-under-the-influence landscape. Those are real, unresolved issues. But the foundational prohibition argument that legalization would produce a teen cannabis use crisis has been empirically disconfirmed.

The bottom line

The federal government has been surveying American teens about cannabis use since 1975. The data shows:

Teen use peaked in 1999, under federal prohibition
Teen use has declined by 20–45% since 2012
Teen use has not increased in any state that legalized adult-use cannabis
2025 data shows the fifth consecutive year at or near historic lows

This is the most robust finding in contemporary cannabis public health research. It deserves more weight in federal policy discussions than it has received to date.

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