Why can't some stoners stop puking?

Imagine you wake up one day and can’t stop vomiting. Maybe it’s food poisoning, you think, or maybe a stomach bug—but weeks and then months pass and you’re still puking regularly. Your doctor has no clue what’s wrong with you and prescribes pain killers to relieve the cramping in your abdomen. Instead, you go home and smoke some weed. You know cannabis helps curb nausea, and smoking temporarily stops you from throwing up. Little do you know that the very thing offering you comfort is the cause of your problems.

For people who suffer from cannabinoid hyperemesis syndrome, what begins as a source of pleasure—smoking pot—eventually becomes a source of extreme pain, sparking mysterious and debilitating symptoms. The condition, which doctors believe is still somewhat rare, usually involves cyclical vomiting and, perhaps most peculiarly, an inclination to find relief in hot baths or showers. It often goes undiagnosed for years.

Eight years ago, Wendell Edgeman, then a 34-year-old pot smoker living in Seattle, began vomiting daily and had no idea why. “As soon as I opened my eyes I would get a pain in my sternum. Then I would throw up for a couple hours,” Edgeman says. “Sometimes it would last for two to three days.” The vomiting bouts would stop then start, stop then start.

One way he relieved the symptoms was to take scorching hot showers. “I needed stifling hot water to relieve the pain,” he told me recently over the phone. “The hottest water I could get. My body was beet blood red afterwards.”

Over the years, Edgeman says he was hospitalized “many times” for dehydration due to relentless vomiting. He had trouble holding down a job, he says, because he was always sick. None of his doctors could come up with a diagnosis, so he underwent two exploratory stomach procedures—neither of which revealed any answers.

Then, early last year, Edgeman was referred to Gregory Reicks, a family medicine doctor in Grand Junction, Colorado, where he was living at the time. Over the years, Reicks had seen other patients who described similar symptoms. The common denominator? They all smoked pot. A lot of pot. Finally, someone cracked the code.

The weed, the doctor explained, was the source of his misery. “He said it was the pot I was smoking—that my THC levels were really high. I thought he was lying to me.”

Edgeman’s disbelief stemmed, in part, from the fact that smoking weed made him feel better. How could a plant that helped curb his nausea be the cause of it? His doctor assured him, “It’s helping you but its hurting you.”

After nearly a decade of suffering, Edgeman took a chance. He stopped smoking weed, and within a month, the vomiting stopped, too. Shortly after, he started a Facebook support page for people who suffer from symptoms of cannabinoid hyperemesis syndrome, or “CHS” for short, to spread awareness.

“I lost everything to CHS,” Edgeman says. He doesn’t want the same to happen to others.

While cannabinoid hyperemesis syndrome has been popping up in an increasing number of published medical case studies, the condition seems to be rare. Hard numbers on people suffering from the syndrome don’t even exist yet, which helps explain why many doctors aren’t familiar with it—and don’t think to offer it as a diagnosis.

Even in popular coverage of pot culture, the condition has received scant attention—save the occasional High Times write-up, or this post from The New York Times, which challenged readers to diagnose a victim of cannabinoid hyperemesis syndrome themselves. Facebook groups like Edgeman’s, however, dedicated to helping fellow suffers, abound.

Diagnosing the syndrome is complicated by the fact that cyclical vomiting is a common symptom of many other medical conditions, including colds, flus, gastritis, food poisoning, and pregnancy. When emergency room doctors are presented with a patient vomiting uncontrollably, cannabinoid hyperemesis syndrome is not a diagnosis that immediately comes to mind.

“During residency I had a handful of patients who had CHS,” says Kathryn Melamed, a medical fellow specializing in critical care in Los Angeles. “The common thread was they all had long-standing nausea and vomiting, but it took awhile to arrive on the diagnosis.”

In fact, in her experience, a patient wasn’t usually correctly diagnosed until his or her third or fourth trip to the hospital. Case studies back up this pattern, finding that many patients, on average, visit an emergency room three to 11 times before getting answers.

“Typically, in a younger patient with no other medical problems, you think of food poisoning, intolerance, stomach flu, or you even consider more serious things like gall stones, or some other sort of stomach or pain disorders,” she explains. Once all those things are ruled out, a doctor might look to rarer condition like CHS—if they know about it.

“It’s not in our medical school curriculum, and it’s not well prescribed,” says Melamed, who says she learned about it by word of mouth from other physicians. “But once you learn to recognize it, you just have to ask—do you smoke marijuana?”

Another clue? If a patient mentions taking frequent showers. As nearly every case study on CHS points out, people with the syndrome find relief in hot water. “This idiosyncratic behavior appears to be learned and is repeatedly used as the only alleviating measure to control symptoms and rapidly becomes a compulsive behavior,” explained a 2011 study. But asking a patient about his or her bathing habits isn’t standard in the emergency room.

It’s not just a lack of awareness of CHS and its symptoms that can make it hard to spot. When patients are admitted to the hospital for several days due to cyclical vomiting, they are put on IVs for hydration and, typically, not using cannabis—which happens to be the cure for CHS—so their symptoms will often go away temporarily. “Once they come to the hospital, you’re taking away any trigger,” explains Melamed. Then when patients return home, they start using weed again, and the condition returns some time later.

So how is that weed, which has been proven to reduce nausea, causes some smokers so much gastric distress?

Experts agree that the most likely cause of cannabinoid hyperemesis syndrome is chronic marijuana use over a long period of time—as in, daily use for years on end. However, because CHS is so new (at least to the medical world), the only information doctors have available comes from case studies—stories about specific individuals—so it’s tough to make generalizations, especially when it comes to who will be affected by the syndrome.

“No predisposing factor is known except the length of the exposure to cannabinoids, with an average of around 10 years with daily usage,” explains Omri Braver, an internal medicine physician at the Soroka Medical Center and Faculty of Health Sciences in Beer Sheva, Israel who has treated several cases. “There might be some other factors—but they haven’t been described yet.”

As more states move to legalize marijuana and the plant becomes more accessible, however, the risk for cannabinoid hyperemesis syndrome increases. According to recent Pew Research data, nearly half of Americans say they’ve tried pot at least once. Since most people aren’t chronic smokers, says Braver, most people aren’t suffering from CHS. But as marijuana grows in popularity and acceptance, that could change.

In fact, a study conducted by the Denver Health Medical Center’s Department of Emergency Medicine actually looked into the prevalence of CHS before and after medical legalization of marijuana in Colorado. Sure enough, the researchers found that “the prevalence of cyclic vomiting visits increased from 41 per 113,262 emergency department (ED) visits to 87 per 125,095 ED visits after marijuana liberalization.” The upshot? The prevalence “nearly doubled,” say the researchers.

While CHS appears to be a rare condition today, as it becomes legal, we may see the case numbers go up. However, there’s no way to tell if all chronic smokers are susceptible to developing CHS or if some people are biologically predisposed.

“It is really impossible to say who, exactly, will develop CHS in the future,” Braver says. Clearly there are chronic smokers out there who never develop CHS. Even more confusing, medical experts aren’t sure why cannabis causes CHS in the first place.

That said, doctors do have some theories. Braver wonders if, for certain patients, pot eventually becomes toxic—causing patients to experience a paradoxical reaction to THC’s typical nausea-fighting effects. “Chronic stimulation by heavy usage with cannabinoids may produce toxicity in sensitive patients,” he says.

Other theories point to CBD (cannabidiol), not THC, as the possible cause. For example, in animal studies research has shown cannabidiol can reduce nausea in low doses but provokes nausea in higher doses. Perhaps that same issue occurs in humans.

For now, the exact pathogenesis remains a mystery.

Yet all hope is not lost. It’s important to remember that while CHS appears to be under-diagnosed, the cure for the syndrome is simple: Stop smoking weed forever.

“Patients with CHS must stop their exposure to cannabinoids to alleviate the symptoms,” says Braver. He goes on to explain that CHS may not reappear immediately after someone takes up smoking pot again, but over time, the toxicity will build until eventually the condition returns.

Which is why Edgeman encourages members of his Facebook support group to quit their smoking habit. Some are hesitant to give it up completely, he says, hoping small doses won’t prove toxic. “I tell them it’s gonna come back,” he says. “Just quit weed.”

The real challenge lies in spreading the word about CHS to both patients and doctors so that people who have it can get properly diagnosed. As Edgeman puts it, “People gotta know.”

Taryn Hillin is Fusion’s love and sex writer, with a large focus on the science of relationships. She also loves dogs, Bourbon barrel-aged beers and popcorn — not necessarily in that order.