This syndrome linked to heavy cannabis use is often misdiagnosed
Story by Sarah Klein
On New Year’s Day 2022, Andrew Whitfield, a 35-year-old fashion designer and stylist in Miami, started throwing up. He didn’t feel under the weather. “It felt random that I threw up,” he said.
A marijuana smoker for 15 years or so, he was used to smoking four or five blunts a day. So he tried smoking to see whether it would help. It didn’t. “I would start to feel really nauseous, my heart rate would pick up, and it got to a point where I couldn’t hold any food or liquids down,” he said. He went to the emergency room after several days, and every test came back normal. He was given antinausea medication, which didn’t help, and was sent home.
Over the next month or so, he realized hot showers helped ease his nausea. It was only after telling a friend what he’d been going through that Whitfield heard about something called cannabinoid hyperemesis syndrome, or CHS.
CHS is characterized by a cycle of abdominal pain, nausea and vomiting after cannabis use. This presents a bit of a paradox, as medical cannabis is often used to alleviate pain and reduce nausea.
Typically, the receptors in your body that are susceptible to cannabinoids get stimulated when you consume THC, the active ingredient, increasing your appetite and tamping down nausea, said Andrew Meltzer, a professor in the department of emergency medicine at George Washington University. That’s why medical marijuana is often used to treat chemotherapy side effects, for example. But in some long-term, heavy cannabis users, the body’s natural cannabinoid system may change. “It either becomes dysregulated or desensitized, and the net effect — which used to be nausea and vomiting protection — now becomes promotion,” Meltzer said.
The cause of CHS is still not well understood, said Kelly Young-Wolff, senior research scientist at the Kaiser Permanente Northern California Division of Research and co-author of recent research on CHS in Drug and Alcohol Dependence. “What we do know is that CHS is most often seen in people who use cannabis frequently over a long period of time, especially daily or near-daily use. We still don’t know why some frequent cannabis users develop CHS andothers don’t,” Young-Wolff said.
People who experience it usually have used cannabis for several years before their symptoms suddenly begin. It’s most common in heavy users and people who smoke cannabis rather than consuming it in other forms, Meltzer said.
Experts estimate about 2.75 million Americans experience CHS each year, but this number may be an underestimate because CHS can be hard to recognize.
CHS was given a diagnosis code in the International Classification of Diseases only in October. “That matters because diagnosis codes are one of the main ways health systems document conditions and researchers track them over time,” Young-Wolff said. “A specific code should make it easier to study how common CHS is, who is most affected and whether rates are changing.”
CHS is primarily seen in ERs because of how extreme the symptoms can be. “A lot of folks feel at their worst, so coming into the emergency department is a natural next step. We definitely see folks in that moment of crisis,” said Mark Conroy, an emergency medicine physician and associate professor at the Ohio State University Wexner Medical Center.
If someone completely stops using cannabis, the symptoms tend to go away. And, like Whitfield, most people with CHS find they feel better when they take a hot shower or bath. As Whitfield did more research online about the condition, he stopped smoking and, over the next two weeks, his symptoms resolved.
That was the right move: So far, the most effective long-term treatment for CHS is to stop using cannabis.
In the short term, people with CHS are often given intravenous fluids and anti-nausea medications in ERs to prevent severe dehydration and quell vomiting. Some people also find relief from a topical cream made with capsaicin, the compound that gives spicy peppers their heat. Others benefit from antianxiety and antipsychotic medications.
But CHS is often hard to diagnose, especially during a first visit, Conroy said. There are countless causes of nausea, vomiting and abdominal pain that could bring someone to the emergency department. “Often this is a diagnosis of exclusion, where you’ve evaluated the person, you’ve ruled out the other more immediately life-threatening causes and you eventually get to this diagnosis,” Meltzer said.
After a few months without symptoms, Whitfield wanted to see whether he could use cannabis again safely. “After just one hit of my friend’s blunt, the next day all the symptoms came back, and they were worse. I had to go back to the hospital because it was so bad,” he said. “It was one of the worst experiences as far as pain I’ve ever dealt with.”
For a couple of weeks after that hospital visit, he would vomit every time he tried to eat or drink anything. He saw a gastroenterologist and got various tests to look for digestive problems. His symptoms ultimately lasted two months before eventually fading.
Untreated, the severe vomiting of CHS can lead to dangerous complications, including dehydration, heart rhythm changes, kidney problems and even death.
Jai Tanninen, 44, an artist in Edmonton, Alberta, thought he might die of his CHS. He had started smoking weed as a teenager and gradually started using it more and more, in part to manage symptoms of post-traumatic stress disorder. Eventually, “I was smoking at every opportunity,” he said. “If I wasn’t at work, I was getting stoned.”
In 2019, mysterious symptoms began. For months, he would throw up once or twice a week and experience agonizing abdominal pain. He sought medical treatment at a hospital and was sent home to recover from what doctors thought was a stomach bug. But Tanninen didn’t think it was a bug. He got sicker and sicker until one day he threw up every five to 15 minutes for eight hours.
His symptoms got so bad during a vacation in Vancouver that he went to a hospital there, where a health care provider mentioned CHS for the first time. Tanninen didn’t think much of it, until his family physician at home brought it up, too. At that point, he immediately stopped using cannabis, but it took six more months until he felt fully recovered.
During the ordeal, he said, “All I could do was throw up, lie in bed and try to take hot baths as much as I could. It was hell.” He was severely dehydrated and undernourished, unable to keep food or fluids down, and, at times, his organs almost failed. He was given IV fluids in the hospital to keep him alive and antinausea medication to try to manage the vomiting, but it didn’t help. “The only thing that alleviated symptoms was hot baths — as hot as you can stand,” he said.
Eventually Tanninen’s symptoms went away. By 2023, he assumed enough time had passed that he might be able to safely try cannabis again. It was one of the only things that helped his PTSD-related insomnia, he said. He used mostly CBD products and edibles this time, but after about a month of using cannabis once a week, his symptoms started again. Although he immediately stopped using cannabis, he felt sick for months. “The entire summer of 2023 I was sick in bed, vomiting,” he said.
CHS often comes back if people attempt to use cannabis again. Meltzer has seen people whose CHS symptoms are triggered by secondhand cannabis smoke or even the smell. “The way I describe it to patients is that they took cannabis for a while, their bodies developed a reaction to it, similar to an allergy, and now they’re sort of ‘allergic’ to it, so repeat exposures are going to create this condition,” Meltzer said.
It’s unclear exactly why this happens, but the theory is that it takes a long time for the body to return to baseline, Conroy said. “I’ve seen individuals who have had episodes for several months, even after quitting. Everyone’s body seems to react differently in terms of the recovery from it.”
One thing a lot of people with CHS have in common, though, is that hot showers and baths bring relief.
Heat and pain receptors in the skin activated by high temperatures might be why baths and showers help, but more research is needed, Meltzer said. Topical capsaicin cream may be helpful to some people for the same reason.
Hot baths and showers are so common among people with CHS that emergency physicians will often ask whether someone has tried this tactic and whether it has provided any relief as part of the diagnostic process, Conroy said.
The only way to prevent CHS entirely is to not use cannabis, Young-Wolff said. If you do use it, consuming it in lower doses and less frequently may help prevent side effects. “Higher-potency THC products may also play a role, although we still need better research on how risk varies by dose, potency, product type and mode of use,” she said. And although most cases of CHS are associated with smoking cannabis, other forms aren’t necessarily safer. “CHS has been reported with different forms of cannabis, so switching from smoking to edibles should not be assumed to prevent it,” she said.
Cannabis, in effect, is “a medicine which is poorly studied, poorly regulated, highly accessible and being taken in really large amounts for a long period of time,” Meltzer said. “This is an active pharmaceutical agent, and while in low doses it’s probably not a big deal for most people, in high doses and long exposure, there are clearly negative side effects.”
If you’re using cannabis medically, talk openly and frequently with your health care provider to make sure the dose and potency you’re using is safe, Conroy said.
Whitfield wishes he had known it’s possible to get sick from smoking too much, rather than believing any and all cannabis use is harmless, he said. “It’s medicinal for a lot of people, so that was the last thing that I expected to experience or hear about,” he said. He also wishes more medical professionals knew about CHS so his symptoms might have been recognized sooner. He has learned most of what he knows about CHS through his own research and Instagram accounts devoted to the condition.
Tanninen also wishes he had learned about CHS earlier. “Maybe I wouldn’t have suffered for so long,” he said. ChristopherBlackwell
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