Public health experts are blaming a surge in unregulated marijuana, following state laws legalizing the drug, for driving a 97% rise in addiction symptoms among adults ages 40 to 50 since 2017.
University of Michigan researchers reported this month that an annual analysis of self-disclosed drug use in National Institutes of Health surveys found the share of the 40- to 50-year-old age group with cannabis use disorder symptoms almost doubled from 3.3% in 2017 to 6.5% last year.
Funded by the National Institute on Drug Abuse, the study notes that the disorder occurs when people consume large amounts, use marijuana longer than expected, feel unable to stop, persist in dangerous circumstances, suffer withdrawal symptoms or quit their responsibilities.
“This is not just using cannabis occasionally without any serious consequences,” Megan Patrick, the study’s lead researcher, told The Washington Times. “This index is based on individuals reporting that their cannabis use has negative impacts on their life.”
The study found daily marijuana use hitting record highs among young and middle-aged adults in 2025, including 11.8% of those ages 19 to 30, up from 6.9% in 2015, and 8.5% of people ages 35 to 50. The university received federal funds to study 18-year-olds starting in 1974, gradually expanding to include all ages.
About 11.4% of young adults surveyed in 2025 reported using intoxicating hemp-derived THC products such as Delta-8, Delta-10 and HHC in the past year.
At the same time, the study flagged “historically low rates of cigarette smoking and a decline in alcohol consumption.”
Ms. Patrick said the research confirms that the “significant impairment” of a growing number of marijuana users has become a major health problem.
“We need to put resources into education about the negative effects of cannabis and treatment for those who are struggling,” she said. “Medical providers should also be aware that an increasing percentage of U.S. midlife adults are dealing with symptoms of cannabis use disorder.”
Nora Volkow, director of the National Institute on Drug Abuse, said the findings are consistent with her federal agency’s estimate that 30% of all cannabis users are addicted.
“Many factors contribute to this trend, including increased use of cannabis to self-treat medical conditions and declining public perceptions of risk,” Dr. Volkow, an addiction psychiatrist, said in an email. “As more states legalize cannabis use, access has increased, with greater dispensary density and proximity to homes linked with increased use among adults.”
She praised the Trump administration’s recent decision to reclassify marijuana for “reducing research barriers,” despite it remaining illegal at the federal level.
The National Institute on Drug Abuse estimates that heavy and frequent marijuana consumption increased fifteenfold from the early 1990s to 2022. Dr. Volkow singled out social media as “a key marketing tool” normalizing the consumption of more psychoactive strains.
Research has long linked marijuana to higher rates of unproductivity, hospitalization and impaired driving. Multiple federal studies cite increased health risks for suicide, stroke, heart attack, psychotic disorders, uncontrollable vomiting and chronic lung conditions — all of which increase significantly as users reach retirement age.
Doctors and industry analysts not connected to the study concurred that legalization has been the key factor driving up addiction in recent years.
“Cannabis is simply more available and more normalized than it was five years ago, much less nine years ago,” said Dr. Kristen Worth, a Minnesota physician and self-described “cannabis practitioner” whose telehealth company prescribes medical marijuana to 2 million patients internationally.
“That access means more adults are self-treating and self-medicating without talking to a doctor about it first,” she added.
Experts say legalization has triggered a surge in unregulated dispensaries hawking gummies and other products with dangerous amounts of tetrahydrocannabinol. Also known as THC, the psychoactive substance can produce intense nausea and “scream-vomiting” in higher concentrations.
“Policymakers and the public need to recognize that the cannabis industry is every bit as profit-seeking and aggressive as the tobacco industry,” said Keith Humphreys, a Stanford University psychologist who researches addictions. “These are not anti-materialist hippies in tie-dye shirts; they are ruthless business people who make most of their money by fostering addiction.”
A Gallup poll published Monday found that 17% of adults surveyed in July reported using marijuana, matching a record high in 2023. That included 15% who reported consuming edibles, such as gummies.
The same poll found that 11% reported smoking cigarettes and 54% said they drank alcohol, both record lows. About 9% said they vaped and 4% used nicotine pouches.
Jerry Joyner, a Texas-based cannabis advocate, said medically unsupported health claims for marijuana have worsened the trends.
“It’s legal, it’s everywhere, and somebody slapped a ‘wellness’ label on it,” Mr. Joyner said in an email. “Rebrand a drug as self-care and watch the numbers run.”
He said it is time to restrict cannabis advertising and accurately label its increased psychoactive potency to “tell people the truth” that natural does not mean harmless and legal does not mean safe.
Some doctors warned against scapegoating legalization for the problem. They called on the government to regulate cannabis in the same way as alcohol and cigarettes, not ban it.
“It is a simplification to state that legalization was the sole cause of this increase,” said Dr. Allen Masry, an addiction psychiatrist and medical director of All in Solutions, a network of treatment centers. “Marijuana use and the number of individuals who experience problems will continue to be high until our prevention and treatment infrastructures develop sufficiently to meet the demand.”
Dr. Charles Smith, medical director of the Agape treatment center in Fort Lauderdale, Florida, noted that self-reported symptoms are not the same as a diagnosis.
“Rather than continue to emphasize prohibition through moralizing, policy should shift toward risk reduction,” Dr. Smith said. “This includes providing accurate labeling regarding potency, issuing warning labels for all cannabis products, creating rules for responsible marketing practices, implementing screenings for cannabis use disorders and ensuring accessibility of treatment.”
Legalized liability
Dozens of states have legalized marijuana for medical or recreational use over the past decade, prompting a spike in usage.
Cannabis remains illegal under all circumstances in just five states: Idaho, Kansas, Nebraska, Wyoming and South Carolina.
“Based on questionable science, many state jurisdictions decided that legalizing cannabis would be an overall benefit to society,” said Henry Maxwell, a Colorado-based addiction counselor and former addict. “However, this seems to me to be largely a financial incentive, as cannabis tax dollars are being used to fund schools, roads, etc.”
The average marijuana plant has jumped from 1% to 3% THC content in the 1970s to 18% to 23% today, according to Smart Approaches to Marijuana, which tracks the harms.
Kevin Sabet, president of Smart Approaches to Marijuana, said the University of Michigan study “should alarm anyone who was told legalization wouldn’t increase marijuana use or addiction.”
“More customers using stronger products more often is not an accidental consequence of commercialization,” Mr. Sabet said. “It is the addiction-for-profit business model working exactly as intended.”
A sweeping review of randomized clinical studies published Nov. 26 in the Journal of the American Medical Association found “insufficient evidence” to support most medical benefits for cannabis and cannabinoids, including the popular claims that they help treat insomnia and acute pain.
The review flagged cardiovascular and psychiatric health risks from medical marijuana use and urged doctors to warn patients more clearly of these dangers.
Regulating addiction
A growing body of research shows that legal, medical and safety risks are surging as more people use marijuana.
Quest Diagnostics estimates that cannabis accounted for 52.5% of positive hair drug tests conducted at workplaces last year. The nation’s leading drug-testing lab found the share of marijuana-positive workers increased by 58.9%, from 9.5% of hair tests in 2021 to 15.1% last year.
“Our data suggests that a sizable minority of the American workforce uses drugs, principally marijuana, on a recurring or chronic basis,” said Jason S. Hudson, Quest’s scientific and laboratory director.
“This is particularly critical in safety-sensitive industries, where even a small lapse in judgment can have serious consequences,” he added in an email.
Aaron Hall, a Minneapolis business lawyer who advises employers on workplace drug policies, said a 2023 Minnesota law legalizing recreational marijuana prevents firing workers who get high on the job.
“A company has to offer the worker a chance to enter counseling or rehab first,” Mr. Hall said. “Only if the worker refuses, or quits the program, can the employer fire that worker.”
Most experts predict that addiction will subside only after the government restricts marijuana and addicts find better ways to soothe their pain.
“A conventional wisdom is that excise taxes are the most efficient way to restrain the harms from problem use of psychoactive drugs,” said Jonathan Caulkins, a public policy professor at Carnegie Mellon University. “They just need to be paired with greater enforcement against illegal [sellers] who compete unfairly with licensed producers, but that is something the country has lacked the political will to implement.”
He noted that increased taxes and decreased advertising have effectively discouraged cigarette smoking and said businesses could post and enforce “no marijuana” signs, similar to “no smoking” notices.
Social worker Justin Szela, clinical director at Pinnacle Peak Recovery in Scottsdale, Arizona, urged medical providers to help patients find other ways of managing stress, sleep and loneliness.
“People are better able to sustain recovery when they have found alternative methods to use instead of drugs to serve the same purpose,” Mr. Szela said.
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