LoginHigh-potency cannabis fuels state debates over psychosis and addiction risks
Cannabis flower rests on a rolling tray, surrounded by a pack of rolling papers, a grinder and a lighter. Lawmakers in a handful of states this year have introduced legislation to impose stricter THC limits on certain cannabis products. Photo by Amanda Watford/Stateline)
When her son was a teenager, Connecticut mom Amy Wadsworth said, he was the type of kid parents rarely worry about.
He played sports, cared about his health and stayed away from drugs. In 2018, when he left West Hartford to start his freshman year at American University in Washington, D.C., she expected his biggest challenge would be adjusting to college life.
Instead, she said, he began using cannabis to cope with social anxiety and as a sleep aid.
Within months, Wadsworth’s son was calling home in the middle of the night, terrified and disoriented.
Over the next several years, his behavior became increasingly erratic, he had psychotic episodes and he was eventually diagnosed with severe cannabis use disorder. That’s when a person’s marijuana use becomes difficult to control and begins interfering with daily life.
Now 25, Wadsworth’s son has spent much of the past several years cycling through hospitals and treatment programs across the country.
“It’s definitely changed the trajectory of his life,” Wadsworth said. “It did nothing but harm him, literally harm every facet of his life — every facet, physical, mental, everything.”
States have spent the past several decades debating whether to legalize cannabis. Now, they are debating how intoxicating legal products should be.
A growing body of research suggests that frequent use of high-THC cannabis increases the risk of cannabis use disorder, psychosis and other mental health problems for users, particularly adolescents and young adults. In response, lawmakers in some states this year have moved to impose stricter potency caps, while others have scaled back or rejected such measures amid industry opposition and uncertainty over research findings.
While cannabis flower once commonly contained THC levels in the single digits, many products sold legally today contain 15% to 20% THC or more. Concentrates — such as waxes, oils and shatter — can exceed 80%.
About 15% of Americans ages 12 and older reported using marijuana in the past month in 2024, according to the Substance Abuse and Mental Health Services Administration. And about 3 in 10 people who use cannabis have cannabis use disorder, according to the federal Centers for Disease Control and Prevention.
Some public health researchers and addiction specialists argue that public perceptions of marijuana have not kept pace with the growing availability of high potency products. They say broader legalization efforts — including the federal government’s recent move to reclassify medical marijuana as a less restrictive drug under the Controlled Substances Act — may reinforce the belief that cannabis is harmless.
“Moving cannabis from Schedule I to Schedule III doesn’t help me save lives by decreasing the perception of that risk,” said Dr. Alta DeRoo, the chief medical officer of the Hazelden Betty Ford Foundation, one of the largest nonprofit treatment providers for addiction and mental health. DeRoo also is a board-certified addiction medicine physician and OB-GYN.
Some state efforts to impose potency limits have been stalled by resistance from the cannabis industry and questions about how far governments should go in regulating a legal product.
In Connecticut, lawmakers this year reinstated a 35% THC cap on flower just weeks after voting to eliminate it. Lawmakers from both sides of the aisle said they were concerned about the potential public health effects of increasingly potent marijuana products.
At the same time, the legislation moved forward with other cannabis market expansions. Lawmakers removed a 70% THC cap on concentrates, increased the amount of THC allowed in certain cannabis-infused beverages and expanded the market to include products such as topicals, tablets and capsules.
Proposals to cap THC potency have surfaced in statehouses across the country for years. This year, lawmakers in California, Georgia, Mississippi, Oklahoma, Oregon and South Dakota introduced similar measures, though most did not advance.
Georgia Republican Gov. Brian Kemp signed a law in May that removes the state’s previous 5% THC potency cap starting July 1. The new law will also add a 12,000 mg possession limit for registered medical cannabis patients and allow patients over 21 to vaporize medical marijuana.
‘A perennial debate’
Lawmakers across the country have proposed a range of measures aimed at limiting the potency of cannabis products.
In Washington state, Democratic state Rep. Lauren Davis has spent years trying to place guardrails on high-potency cannabis products. Since 2020, she has introduced at least five bills that would have capped THC levels in concentrates or imposed safeguards, including age restrictions, warning labels and a higher tax rate on products with elevated THC levels.
Most of those measures were thwarted by opposition from the cannabis industry, Davis told Stateline.
Industry groups and cannabis businesses argued that Washington’s existing regulations already protected consumers and kept cannabis away from minors. Opponents also warned that limiting high-THC products would drive consumers to the illicit market, hurting legal businesses and exposing users to unregulated, possibly contaminated products.
“(The industry) then went on to basically rain down all fire and brimstone and crush every bill that I’ve ever attempted in this area,” Davis said.
The only proposal to become law was a 2024 measure that requires retailers to warn customers about the association between high-potency THC products and psychotic disorders.
Washington state does not currently impose THC caps on flower or concentrates, but it does set limits on edibles and beverages.
Nearly all states have some form of medical-only or hybrid medical and recreational cannabis program, but just eight states, Connecticut, Mississippi, Montana, Nevada, New Mexico, Oregon, Rhode Island and Vermont, have potency caps on some products, including flower, according to the National Conference of State Legislatures. Potency limits on edibles are far more common.
“This is a perennial debate that comes up in Vermont and elsewhere around higher potency products,” said James Pepper, who chairs the Vermont Cannabis Control Board, the agency that regulates the state’s market.
“I feel like the concerns are certainly real,” he added.
In Oklahoma, a recent incident in which a 4-year-old boy was hospitalized and remained unconscious for more than a day after his parents said he ingested a 1,000 mg edible found at a playground has added to growing debate over high-potency cannabis products in the state.
“We know that some of our medical patients truly do need higher potency products, but do we really need a 2,000 milligram gummy available for anyone with a patient license to purchase in an Oklahoma dispensary?” said Adria Berry, the executive director of the Oklahoma Medical Marijuana Authority, which oversees the state’s medical market.
Oklahoma Republican Gov. Kevin Stitt also signed a measure into law last month that will take effect in November, adding stricter packaging and labeling requirements, including restrictions intended to prevent products from resembling candy or appealing to children.
While some industry experts acknowledge the potential harms, they say the focus should be on consumer education and clear information about potency and effects, rather than new restrictions.
An official with Trulieve, a cannabis company that operates dispensaries in eight states, told Stateline that its products are independently tested and that potency information is available for customers to review and ask questions about, including a product’s effects.
“We believe that that piece of information is critical for a consumer to make an educated decision on what type and what potency of product they are looking to consume,” said Lauren Niehaus, Trulieve’s executive director of government relations.
Some advocacy and trade groups, such as the National Cannabis Industry Association and the National Organization for the Reform of Marijuana Laws (NORML), argue that policymakers should steer consumers into tightly regulated legal markets rather than imposing blanket THC caps that could push some users back to illicit sellers. They say that accurate labeling, child-resistant packaging and public education campaigns are the best strategies to protect public health and prevent youth access.
“It’s undoubtedly safer and better for public health outcomes to regulate these products,” said Adam Rosenberg, who chairs the board of the National Cannabis Industry Association.
Paul Armentano, NORML’s deputy director, said potency caps oversimplify the risks of cannabis products and fail to account for how consumers actually use them. Consumers view ultra-potent products as a novelty, he said, and ultimately gravitate toward lower-potency options.
“When you look at state-tracked sales in legal states, cannabis flower or botanical cannabis still outsells every other product, and I would dare say it’s because that is the most moderate to low potency product available on the shelf, and that’s what most people want,” Armentano said.
Armentano also argued that some of the strongest calls for THC limits come from opponents of legalization, who see potency restrictions as a way to gradually roll back access to legal cannabis.
What the research says
A study published earlier this year in JAMA Health Forum found that adolescents who use cannabis, including products with higher potencies, had a significantly increased risk of developing psychotic and bipolar disorders, along with higher risks of depression and anxiety. The research followed about 463,000 adolescents in Northern California between ages 13 and 17 and tracked outcomes into early adulthood. The study did not, however examine whether the use of higher-potency products is more likely to cause psychotic and bipolar disorders.
But other research has linked frequent use of high-potency cannabis to a greater risk of psychosis and psychotic disorders, particularly among heavy users. Several studies have found a dose-response relationship, meaning the risk tends to rise as THC concentration and frequency of use increase. Experts caution, however, that many studies cannot definitively prove that cannabis causes psychosis and that individual risk varies widely.
Other research suggests the risk of developing psychosis may be higher for adolescents and young adults, whose brains are still developing, as well as people with existing mental health conditions or a family history of psychotic disorders.
“I’ve seen patients come through our facilities where they haven’t done any other drugs other than just high-potency marijuana, and their psychosis is remarkable,” said DeRoo, of the Hazelden Betty Ford Foundation. “They don’t have a grasp of reality. They come in seeing things, they come in believing things, alternate realities.”
John Puls, a psychotherapist and addiction specialist in Florida, has seen similar patterns in his practice at Full Life Comprehensive Care, particularly among adolescents and young adults using high-potency products.
He said families often don’t believe cannabis alone could be driving such dramatic changes. Beyond psychosis, he added, cannabis can chip away at more ordinary parts of life: Motivation drops, executive functioning suffers, patients miss appointments or forget obligations, and short‑term memory and relationships start to fray.
Some medical and industry experts say that cannabis can provide meaningful relief for some people, including those undergoing cancer treatment or who have chronic pain. But there is very little consensus on appropriate medical uses, dosing and long-term effects, particularly as products vary widely in potency.
“If there’s no standardized testing of products, or if there’s no enforcement of potency limits, then we might be putting people at more risk,” said Dr. Smita Das, an adult addiction psychiatrist and a clinical professor at Stanford University School of Medicine.
Stateline reporter Amanda Watford can be reached at awatford@stateline.org.
This story was originally produced by Stateline, which is part of States Newsroom, a nonprofit news network which includes Wisconsin Examiner, and is supported by grants and a coalition of donors as a 501c(3) public charity.
