Americans are consuming stronger cannabis than ever before. What are the risks?
How potent is today’s cannabis?
Over 48 million Americans are regular consumers of cannabis—and they’re getting stoned on a product that’s four or more times stronger than the weed Baby Boomers smoked in their youth. Since Colorado and Washington state legalized recreational use in 2012, 24 states plus Washington, D.C., have followed suit. On Election Day, residents will vote on legalization in Florida, South Dakota, and North Dakota. Cannabis has blossomed into a $33 billion industry selling pre-rolled joints, vape pens, oils, drinks, flavored gummies, lollipops, and more. Cannabis offers some therapeutic benefits for pain, nausea, insomnia, and other conditions, and most moderate users don’t experience negative side effects from getting a relaxing buzz. But legalization has led to more chronic users—about 18 million people use cannabis daily—and more people suffering from dependency and negative side effects. The average concentration of THC—the intoxicating compound in marijuana plants—was 4 percent in weed sold in 1995. In 2021, it had soared to 15 percent. Many products now have a THC concentration of 40 to 70 percent. Few states set maximums. “There’s a difference in legalizing the original cannabis on the planet and the products that exist today,” said Yasmin Hurd of Icahn School of Medicine’s Addiction Institute.
What risks does this pose?
Almost a third of adult users reported symptoms of cannabis use disorder in 2022—meaning they continue to use despite suffering social, work, and health problems from the drug. About 3 million are considered addicted. Some heavy users also develop cannabinoid hyperemesis syndrome (CHS)—severe nausea and vomiting that, through dehydration, can lead to seizures, cardiac arrest, and kidney failure. About 6 million Americans are estimated to suffer from CHS, and it has killed at least eight people in the U.S. Scientists suspect CHS is connected to how marijuana interacts with the body’s endocannabinoid system, which helps regulate functions like digestion and pain perception. Cannabis-related diagnoses rose more than 50 percent from 2016 to 2022, affecting 522,000 people. Heavy use appears to increase the likelihood of heart failure and may affect male fertility.
Can THC affect mental health?
Doctors report treating cannabis users for symptoms of psychosis, including paranoia and delusions. These symptoms are usually temporary, but for those with a genetic susceptibility, research has found, frequent cannabis use can trigger schizophrenia and other chronic mental health disorders. People regularly consuming marijuana with at least 10 percent THC were almost five times more likely to develop a psychotic disorder than people who’ve never used it, according to a recent study. Up to 30 percent of schizophrenia cases among Danish men in their 20s could be attributed to cannabis use disorder, another study found. “Cannabis should not have a free pass as something that is safe because it’s legal—or safe because it’s natural—because actually it clearly causes harm in a number of my patients,” said Scott Hadland of Mass General for Children.
How are young people affected?
Studies show that consuming more potent cannabis more frequently in the teens and 20s carries greater risks, including for developing life-long psychiatric disorders. A Canadian study found that teens consuming cannabis were 11 times likelier to develop a psychotic disorder than peers who never consumed. It’s illegal to sell cannabis to people under 21, but among 18- to 25-year-olds, there were more than 4.5 million daily or near-daily users in 2022—and about 4 out of 5 met the criteria for cannabis use disorder. “I have kids asking me all the time, ‘What if I do this just once a month, is that OK?’” said Sharon Levy, director of Boston Children’s Hospital’s Adolescent Substance Use and Addiction Program. “All I can tell them is that there’s no known safe limit.”
How does THC use lead to the psychiatric disorders?
Research suggests that in young people it can affect development of the cerebral cortex, home to the brain’s executive function and reasoning. The cortex doesn’t reach full maturity until about age 25. A 2021 study of adolescents found an association between cannabis use and thinning of the prefrontal cortex. The more cannabis exposure a teen had, the more severe the thinning. Teens with this thinning suffered from strong impulsivity; in adolescent rats given THC, it also affected memory and behavior.
Are there ways to reduce harm?
Researchers are calling for better public health messaging about potential side effects, particularly about cannabis use disorder and CHS. But as the wave of state legalization builds, the Drug Enforcement Administration is reclassifying marijuana from a Schedule I drug—alongside LSD and heroin—to a Schedule III substance, like Tylenol and ketamine. Schedule III drugs are considered to have lower risk of dependency and carry fewer restrictions. Many scientists and doctors who study cannabis or treat cannabis users warn that its potential to harm users, especially young ones, is widely underestimated. “There is no other quote-unquote medicine in the history of our country where your doctor will say, ‘Go experiment and tell me what happens,’” said neuroscientist Carrie Bearden.
The hemp loophole
When Congress legalized farming and selling hemp in the 2018 Farm Bill, it inadvertently legalized the intoxicating compound Delta-8 THC, sometimes called “diet weed.” Derived from hemp, Delta-8 produces a similar high to the Delta-9 form of THC in the cannabis plant, but is less potent. Delta-8 is now available in gummies, infused drinks, and cereals, among other products. More than 11 percent of high schoolers have consumed it. But users are increasingly calling poison centers. Calls connected to Delta-8 increased 82 percent from 2021 to 2022, involving more than 3,300 users. Adverse effects include loss of consciousness and hallucinations. There has been no substantial research on how Delta-8 works or what it does. The Food and Drug Administration warned of public health risks in 2022, but it doesn’t regulate Delta-8 products. Since 2018, at least 17 states have banned Delta-8, and others are considering doing the same. “I don’t think anyone thought this was going to happen when the farm bill passed,” said Ziva Cooper of UCLA’s Center for Cannabis and Cannabinoids. “The genie is kind of out of the bottle.”