Cannabinoid Hyperemesis Syndrome Rises with Legalized Cannabis Use

Recreational cannabis use is now legal in 24 U.S. states. After Illinois legalized it, in 2020, James Swartz started to keep an eye out for any changes in public health that might stem from more widespread marijuana use. A professor of social work at the University of Chicago, he still remembers when he and his colleagues learned about the rise of a distressing condition that seemed linked to chronic marijuana usage. “We started seeing more and more clinical reports and case studies in the literature about this syndrome,” he says. “So we were curious: Is that happening here?”

They found that indeed, cannabinoid hyperemesis syndrome (CHS)—which can include a symptom colloquially called “scromiting,” a portmanteau of “screaming” and “vomiting”—seemed to be on the rise in emergency departments nationwide. In 2025, the condition even got its own ICD 10 code, allowing doctors to enter it more specifically into medical records. The condition is still poorly understood, and recently, physicians publishing in JAMA wrote a primer on the disorder.

An important backdrop to the rise of CHS is a condition called cyclic vomiting syndrome, or CVS, says Dr. Thangam Venkatesan, a professor at the Ohio State University who is an expert on CVS and an author of the new paper. “It has episodes of nausea, vomiting, belly pain, headache, and this affects both children and adults,” she says. During episodes, people vomit or retch four or five times an hour, and episodes can last several days, before abating for weeks or months. Understanding and avoiding triggers is key to treating the disorder.

CHS was first described in 2004 in Australia, when doctors carefully followed patients with cyclical vomiting who were habitual cannabis users. It presents similarly to CVS and usually occurs after people have been using marijuana for some time, sometimes as a treatment for other disorders, and involves abdominal pain and vomiting that recedes after people stop cannabis use. The pain can be so intense for some people that they may scream while they vomit. (About the “scromiting” label: Venkatesan doesn’t use it and calls it “a fairly derogatory term.”)

During episodes, people can seek relief by taking very hot baths and showers, though it’s not clear why this helps, says Venkatesan—nor is this coping method unique to CHS. “Close to half the patients with cyclic vomiting who have never used cannabis also exhibit the hot shower bathing behavior,” she says. “This is very peculiar.”

It’s possible that some of the increase in documented cases comes from more ER doctors recognizing what they’re seeing as a cohesive syndrome, says Venkatesan. But the rise seems to coincide with a sharp increase in the potency of the forms of cannabis now available and an increase in cannabis use generally. Concentrations of THC, the primary psychoactive compound in marijauna, used to be around 1-3% in dried plants, and now they may be higher than 15%—and as high as 95%.

“It's a completely different product, even in medical dispensaries,” than before legalization, Venkatesan says. She notes that people may not be aware of the potential for syndromes like CHS when they start using cannabis, and the picture is complicated by the fact that many heavy users do not experience these symptoms, she says.

“You really increase your chances of this with frequent use of high-potency products for an extended period of time,” says Swartz. “So I would say, be careful of the products that you're using, be mindful of the potency and the frequency with which you're using. It's not a fun condition to have.”

The rise of legalized cannabis has also been accompanied by an increase in schizophrenia cases, research has found; one study in Ontario found that cases associated with cannabis-use disorder nearly tripled in recent years. Even before legalization, there was a known link between psychosis and prior cannabis use in young people, suggesting that in some, there may be a genetic predisposition to schizophrenia that is exacerbated by cannabis. Daily use of high-potency cannabis is associated with a nearly five-fold increase in schizophrenia risk, another study found.

Do people with CHS also have psychiatric conditions? Studies found that mental-health conditions and CHS do tend to co-occur, says Swartz. But whether that’s because people are self-medicating with cannabis and thus predisposing themselves to CHS, or whether CHS and mental-health conditions occur together for other reasons isn’t clear.