Cannabis use disorder rates among American adults have climbed sharply between 2021 and 2024, according to a new study published in JAMA Psychiatry, but the researchers and policy experts who have examined the data broadly agree that the findings do not justify returning to prohibition.
The study, led by National Institute on Drug Abuse Director Nora Volkow and three co-authors, drew on data from more than 180,000 survey participants in the National Survey on Drug Use and Health (NSDUH), according to MedPage Today. Among men aged 18 or older, the proportion reporting at least two symptoms of cannabis use disorder (CUD) rose from 7.3 per cent in 2021 to 9.3 per cent in 2024. Among women, the equivalent figure moved from 4.5 per cent to 5.6 per cent.
The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders defines CUD against 11 criteria: a strong desire to use cannabis, consuming more than intended, devoting substantial time to use or recovery, forgoing other activities, use in physically hazardous situations, unsuccessful attempts to cut back, tolerance, withdrawal symptoms, cannabis-related problems at work or school, impairment of relationships, and continued use despite negative effects. Two or three symptoms constitute mild CUD; four or five, moderate; six or more, severe.
Moderate-to-severe CUD rose from 3.1 per cent to 4.1 per cent among men and from 1.7 per cent to 2.5 per cent among women over the same period. The increase was most pronounced among men aged 35 or older and women aged 21 or older, though moderate-to-severe CUD remained most prevalent overall in the 18-to-20 age group.
In absolute terms, those percentages translate to a rise from 15.3 million to 19.4 million American adults with cannabis use disorder between 2021 and 2024.
What the Data Does and Does Not Show on Cannabis Use Disorder Rates
The NSDUH data do not include information about the potency of cannabis products used by respondents, so the study cannot directly link the increase in cannabis use disorder rates to higher THC concentrations. Volkow acknowledges the gap. ‘The challenge is that we lack comprehensive data on the types of cannabis that people are using, including the concentrations of delta-9-THC and other cannabinoids, and how those relate to addiction potential,’ she said.
Separately, the SAMHSA press release for the 2024 NSDUH records that past-year marijuana use among Americans aged 12 or older rose from 19.0 per cent in 2021 to 22.3 per cent in 2024. The SAMHSA 2024 NSDUH annual report also shows that among past-month marijuana users aged 12 or older, 38.0 per cent vaped the drug; among users aged 18 to 25, that figure rose to 52.0 per cent.
Although cannabis use fell among Americans aged 25 or younger, it increased in older cohorts, a pattern consistent with the broader diversification of the user population as legalisation has expanded.
A Policy Debate That Prohibition Cannot Settle
Jodi Gilman, director of neuroscience at the Massachusetts General Hospital Center for Addiction Medicine, is not surprised by the trend. ‘It’s not surprising that there are more cannabis use disorders with this flooding of the marketplace with highly potent products,’ she said. The best clinical response, she argues, is not incarceration: it is ‘motivational interviewing or cognitive behavioral therapy.’
Jeffrey A. Singer of the Cato Institute, a practicing surgeon and health policy expert, cautioned against treating the JAMA findings as a mandate for stricter controls. CUD should not ‘become the basis for a new moral panic,’ he said, adding that the right response is to ‘educate people about cannabis’s risks’ rather than assume that ‘prohibition is the answer.’ He drew a parallel with alcohol: ‘We don’t ban alcohol because some people use it unwisely or develop alcohol use disorder. Autonomous adults should remain free to make choices others consider unwise so long as they don’t violate the rights of others.’
Jonathan Caulkins, a drug policy expert at Carnegie Mellon University, occupies a more cautious middle ground. A ‘total laissez faire, caveat emptor approach,’ he argued, ‘is going to mean that many millions of people have lives substantially damaged.’
The debate has a live legislative dimension. Smart Approaches to Marijuana, which opposes legalisation, is using research such as the JAMA Psychiatry study to support a Massachusetts ballot initiative formally titled ‘An Act to Restore Sensible Marijuana Policy.’ The measure is now headed for the 2026 general election ballot after a legal challenge was rejected, according to The Hill, not, as originally reported, a vote this autumn.
Under the initiative’s terms, as set out in the official Massachusetts government summary, adults aged 21 or older could possess up to one ounce without penalty; possession of between one and two ounces would become a civil offence carrying a $100 fine and forfeiture. For those under 21, possession of up to two ounces would similarly be treated as a civil offence, according to Ballotpedia. The organisation’s action committee has contributed more than $1.5 million to the Coalition for a Healthy Massachusetts, the initiative’s principal sponsor.
Whether the ballot will shift public opinion remains unclear. Cannabis Business Times cited polling showing that 55 per cent of Massachusetts voters oppose repealing the state’s cannabis laws. With the 2026 vote a year away, the JAMA data will feature prominently in the campaign arguments on both sides.
