The changing marijuana landscape: What you need to know

Today’s cannabis industry is almost unrecognizable in comparison with the counterculture symbol of the 1960s and ’70s. At that time, marijuana was widely considered an “all-natural” substance, and its psychoactive potency reflected that perception: The average level of tetrahydrocannabinol (THC), the compound responsible for cannabis’s euphoric high, hovered around just 1%. Now, vapes and joints routinely push 30% THC, while dispensary shelves are stocked with concentrates—some boasting 90% to 95% THC—in the form of waxes, edibles, and more (Prince, M. A., & Conner, B. T., Behaviour Research and Therapy, Vol. 115, 2019opens in new window). Once niche, these ultrapotent products have gone mainstream.

In 2024, the U.S. cannabis market was valued at $38.50 billionopens in new window, and it is projected to nearly double in the next 5 years. “It’s a huge public health gamble,” said Aaron Weiner, PhD, an addiction psychologist and executive consultant at the Prevention Research Institute. “Right now, we don’t have definitive research on the long-term effects of these market shifts, but on the ground, we’re seeing a clear relationship between rising potency and negative health outcomes.”

Nearly 18 million Americans now report using marijuana daily or near daily, outpacing the number who drink alcohol that often. Many do so without issue, and some find cannabis a boon for their social and mental well-being. But as the market expands, cannabis users have access to an unprecedented variety of purported antidotes for conditions ranging from insomnia to anxiety to post-traumatic stress disorder. While scientific studies back some medical uses for cannabis, many of these claims have yet to be validated by rigorous studies.

In other words, today’s high-octane cannabis exists in uncharted scientific territory. As consumption increases and dependence becomes more common, psychologists are encountering more patients who use cannabis, sometimes in ways that negatively affect their health. These shifts raise urgent questions: Where are the gaps in research on today’s products? How can psychologists help their patients navigate cannabis use safely? And what do they need to know to separate fact from fiction in this rapidly evolving landscape?

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Cannabis research is lagging behind the drug’s rapid commercialization. For one, products of vastly different THC concentrations are all categorized under the generic term “cannabis,” which Weiner said muddles both market regulation and scientific research. “It’s similar to how the term ‘psychedelics’ covers a wide range of substances, each with distinct effects. The same applies to cannabis, where different derivatives carry tremendously different risk profiles and potential benefits.”

Additionally, several of the seminal studies suggesting that chronic cannabis use has no lasting neurological or psychological effects were conducted on significantly lower potency products than those on the market today (Grant, I., et al., Journal of the International Neuropsychological Society, Vol. 9, No. 5, 2003opens in new window; Pope Jr., H. G., et al., JAMA Psychiatry, Vol. 58, No. 10, 2001opens in new window). Strict federal regulations on marijuana, which remains classified among the most dangerous and least valuable drugs, have stifled research that could compensate for this void of information.

The limited available evidence supports some medical uses for cannabis. Studies show that certain cannabinoids can ease chronic pain and help manage chemotherapy-induced nausea and vomiting (Whiting, P. F., et al., JAMA, Vol. 313, No. 24, 2015opens in new window; The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research, National Academies Press, 2017opens in new window). Some studies also suggest that cannabis use may improve cognitive function in middle-age and older adults, but the mechanisms behind these effects remain unclear (Sagar, K. A., et al., Journal of the International Neuropsychological Society, Vol. 27, No. 6, 2021opens in new window; Watson, K. K., et al., Frontiers of Aging Neuroscience, Vol. 14, 2022opens in new window).

Partly because of its therapeutic potential, last year the U.S. Drug Enforcement Administration recommended reclassifying cannabis from a Schedule I substance, which includes heroin and ecstasy, to a Schedule III substance, placing it alongside prescription medications like testosterone, ketamine, and anabolic steroids (Stringer, H., APA, June 11, 2024). However, there are no high-quality, peer-reviewed studies supporting the therapeutic use of high-THC concentrates specifically (Bidwell, L. C., et al., Drug and Alcohol Review, Vol. 40, No. 6, 2021opens in new window). While many people use these products recreationally without obvious harm, emerging studies on animal and organoid models suggest that prolonged exposure to high THC doses might leave lasting imprints on the brain circuits regulating sleep, memory, mood, and motivation (Stringer, H., Monitor on Psychology, Vol. 54, No. 4, 2023). For at least some human users, these changes manifest as long-term conditions, including addiction and cannabis withdrawal syndrome.

“With more research, we can unpack the good, bad, and ugly of prolonged cannabis use. I’m open to understanding the bad and the ugly, especially if it means we can better inform patients,” said Yasmin Hurd, PhD, director of the Addiction Institute at Mount Sinai within the Mount Sinai Behavioral Health System in New York, home to one of the country’s largest addiction treatment programs.

Hurd believes that more research on both the benefits and risks of marijuana, especially high-THC concentrates, is long overdue. But she also cautions that we don’t need definitive epidemiological studies before acting on product distribution and public education. “If we can smell the smoke, we don’t need to wait until we see the fire before reassessing and potentially changing our environment,” she said.

And from what she’s seen, both in her own hospital and through the eyes of fellow scientists, the smoke is already thick.

Even as pot becomes increasingly potent, the belief that marijuana is not addictive persists. This misconception partly stems from the fact that cannabis dependence develops more gradually than addiction to substances like opioids does. Further, withdrawal symptoms, though unpleasant, are rarely life-threatening like those from alcohol detox.

But myths about cannabis are also fueled by misunderstandings about modern products. Some users assume that because marijuana comes from a plant, it is natural and therefore harmless. In reality, today’s high-THC concentrates are “as close to the cannabis plant as strawberries are to frosted strawberry pop tarts,” according to a report by Beatriz H. Carlini, PhD, MPH, a research scientist at the University of Washington’s Addictions, Drug and Alcohol Institute (Cannabis Concentration and Health Risks, Washington State PRSC Cannabis Concentration Workgroup, 2020opens in new window).

These misconceptions mean that many regular users, including a growing number of adolescents, may consume cannabis without recognizing the risks or the warning signs of dependence. “My goal isn’t to stop people from using cannabis; it’s to make sure they have accurate information to make their own health-related decisions. One of the biggest myths I hear is that cannabis isn’t addictive or doesn’t have harmful effects,” said Weiner, who added that cannabis use disorder is the second most common condition he treats in rehabilitation programs.

Symptoms of cannabis overuse can be subtle but significant: apathy, irritability, difficulty concentrating, social disengagement, and loss of motivation. Withdrawal symptoms follow similar patterns. Frequent cannabis use—weekly or more often, over several months or longer—also raises the risk of more severe conditions, including cannabinoid hyperemesis syndrome (CHS), which is marked by cycles of nausea, vomiting, and severe abdominal pain (“Cannabis Hyperemesis Syndrome,” Cleveland Clinic, 2024opens in new window). One study found that nearly 33% of frequent cannabis users who visited an emergency department met the criteria for CHS (Habboushe, J., et al., Basic & Clinical Pharmacology & Toxicology, Vol. 122, No. 6, 2018opens in new window).

Yet many patients experiencing these effects, as well as the providers treating them, fail to recognize the connection between their symptoms and cannabis use, according to Hurd. She hypothesizes that this is partly because the milder symptoms of cannabis dependence mimic the very conditions, like insomnia or anxiety, that users are trying to self-treat.

While these effects often develop gradually, in some cases, cannabis is associated with temporary psychosis—a sudden break from reality that lasts hours, days, or even months (Murray R. M., et al., World Psychiatry, Vol. 15, No. 3, 2016opens in new window). In an ongoing lawsuit against California’s top-selling marijuana brand, a former adolescent user claims the company’s products led to multiple psychotic episodes (Fahmy, K., Kron4 News, May 29, 2024opens in new window). During one, according to the lawsuit, a police officer found the teenager shirtless and soaking wet after he had jumped into a pool, convinced that a classmate had cursed him with witchcraft.

Cannabis-induced psychosis and other adverse reactions can affect people of all ages, but young users face especially pronounced risks. Hurd’s research links their heightened vulnerability to the endocannabinoid system, a network of natural signaling molecules that fine-tunes the developing brain’s emotional and cognitive regulation. When this system is flooded with high levels of THC, its delicate balance can be thrown off. In 2007, Hurd’s team reported that repeated THC exposure during adolescence altered the structure and function of neurons involved in basic reward processing. In 2019, they confirmed similar disruptions in the prefrontal cortex, which handles higher-order emotional functions related to self-control and decision-making. The researchers’ subsequent work revealed that adolescent rats exposed to high doses of THC showed greater impulsivity and risk-prone behavior as adults—effects that intensified when they were reexposed to THC. When Hurd’s team analyzed data from human cannabis users participating in simulated gambling tasks, they found similar patterns (Neuropsychopharmacology, Vol. 32, No. 3, 2007opens in new window; Molecular Psychiatry, Vol. 24, No. 4, 2019opens in new window; JAMA Psychiatry, Vol. 80, No. 1, 2023opens in new window).

Education and informed decision-making are critical for these young users, according to Susan Collins, PhD, a licensed clinical psychologist, president of the Society of Addiction Psychology (APA Division 50), and codirector of the Harm Reduction Research and Treatment Center at the University of Washington. In recent years, she has worked with an increasing number of adults with cannabis use disorder, many of whom started using as teenagers. Unlike her patients with alcohol or opioid use disorders, who often acknowledge they were aware of the risks, Collins said many of her clients with cannabis dependence were never told about the potential harms. “The first time they hear about it is in my office or at the hospital when something is clearly wrong,” she said.

Some adults may be able to use cannabis safely and in a way that benefits their overall well-being, Hurd and Collins agree. But we must also do better at restricting access for children and adolescents. Teens may ask adults to buy for them, take it from family members, or use fake IDs to purchase products themselves. These trends carry lasting implications. “Healthy children become healthy adults,” Hurd said. “There’s no perfect formula for predicting who is at risk for the worst effects of cannabis. But potency, frequency, and age are undeniably key factors in that equation.”

Once cannabis dependence takes hold, treatment options can be frustratingly limited. For reasons still not fully understood, hot baths and showers can temporarily ease CHS-induced nausea and vomiting. Prescription medications can also help manage withdrawal symptoms like insomnia and appetite loss. However, to date no drug has been approved by the Food and Drug Administration to directly treat cannabis use disorder.

Scientists like Tom Freeman, PhD, director of the Addiction and Mental Health Group at the University of Bath in England, are working to change that. In his lab in the United Kingdom, where cannabis research faces fewer restrictions, Freeman is investigating cannabidiol (CBD)—a cannabis derivative that doesn’t produce a “high”—as a potential treatment. In 2020, he and his team published a randomized clinical trial showing that CBD was more effective than a placebo in reducing cannabis use among people with cannabis use disorder: Participants who took 400 mg of CBD daily cut their cannabis use by about half a day per week, while those who took 800 mg reduced their use by nearly a third of a day per week (Lancet Psychiatry, Vol. 7, No. 10, 2020opens in new window). “Countries around the world are radically changing their cannabis policies, and it’s becoming more and more important to have tools available to treat emerging health risks,” Freeman said.

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For now, therapy remains the primary treatment. Through motivational enhancement therapy and cognitive behavioral therapy, individuals can recognize triggers and develop coping strategies. Therapy may also help those using cannabis to self-medicate underlying conditions like anxiety or depression.

Collins believes this treatment should be as individualized as the reasons people use cannabis in the first place. In her practice, she starts by asking clients why they use cannabis, then she works with them to determine the best approach, whether that means cutting back, quitting entirely, or addressing related stressors. “What addiction looks like for a given person, with their unique constellation of stressors and symptoms, just varies. Treatment has to be specific to that person and their environment,” she said.

She envisions this holistic, harm-reduction approach extending beyond clinical settings to cannabis regulation. “Our relationship with cannabis is as much cultural as it is medical,” she said, explaining that the United States’ history with marijuana has been a pendulum swing of extreme fear and praise. Now, as cannabis enters an era of mainstream acceptance, she believes psychologists and policymakers must strike a balance between destigmatizing and decriminalizing the drug while ensuring consumers have clear, science-based information about risks.

Hurd similarly opposes criminalizing cannabis use but believes that “legalization was the magic wand that opened up Pandora’s box.” She supports tighter potency regulations, such as those in countries like Switzerland and France, where THC content is capped at 1% and 0.3%, respectively. “I’d like to see tax revenues from cannabis sales directed toward education and treatment campaigns,” Hurd added.

Stronger consumer protections could also make a difference. Psychologists and other experts can push for clearer risk disclosures on cannabis product labels, similar to the warnings found on alcohol containers. Currently, labeling requirements vary by state, with many offering only vague cautions like “keep out of reach of children and pets.” Standardized potency measurements could help bridge this gap, too. In 2020, Freeman and his colleagues proposed a “standard THC unit,” set at 5 mg of THC, to serve as a universal reference for all forms of cannabis consumption (Addiction, Vol. 115, No. 7, 2020opens in new window). (Unlike THC percentage values, which indicate the amount of THC relative to a product’s volume or weight, this unit is based on dose, providing a clearer sense of how much active compound a person is consuming across different forms of cannabis products.) A year later, the National Institutes of Health adopted this standardopens in new window for cannabis-related research, but the commercial market has yet to follow suit.

Fixing the patchwork of cannabis regulations is an urgent and long-standing goal, according to Weiner. “Cannabis access should be shaped by public health priorities, not profits,” he said.

To him, the real challenge for psychologists and other clinicians isn’t only policy—it’s perception. In a country where marijuana has been demonized, criminalized, glorified, and commodified in equal turns, getting people to see it for what it truly is—neither miracle cure nor harmless pastime—may be the most important task of all.