A study published in 2012 found that marijuana use may be as high as 40 to 50 percent among male CVS patients. (While studies show that the typical patient for CVS linked to marijuana use is a middle-aged white man, women and minorities are also susceptible.) Uncontrollable vomiting as a result of marijuana use is also sometimes referred to as “cannibinoid hyperemesis syndrome.” But some researchers say CHS should be considered a subset of CVS, and one literature review states that the "only reliable criterion" to distinguish the two is whether the symptoms completely stop after the person stops smoking. The two conditions are otherwise "clinically extremely similar, the researchers write.

So, because I fear throwing up about as much as I fear drugs, I decided to speak to a medical professional to find out how likely it is that the average casual pot smoker will develop CVS.

Robert Glatter, an emergency physician at Lenox Hill Hospital in New York, tells me he saw patients with CVS for years before the wider medical profession realized there may be a link between the syndrome and marijuana use. “I would see people in the emergency department with heavy and chronic [marijuana] use who would have these vomiting syndromes with abdominal pain, and we just didn't know what it was,” he says. He describes CVS as an “underrecognized and underreported” phenomenon. Part of the reason it took so long to draw a link between marijuana use and CVS may be that marijuana is typically thought to reduce nausea. “If you look at the pharmacology of cannabinoids, there are multiple types of cannabinoids, and at low doses, the majority of these cannabinoids are antiemetic,” says Glatter. “But with higher and heavier usage what you develop is this paradoxical effect, this incidence of vomiting and nausea.”

The “higher and heavier usage” part of that statement is paramount. Most cannabis consumers who come to the hospital with CVS symptoms smoke heavily and daily—three to five times per day, at a median of 15 to 16 years, says Glatter. This is not to say that heavy, long-term use of marijuana will lead to CVS, only that it might, and physicians still aren’t sure what makes some people more predisposed than others.

“The exact cause is really unclear,” says Glatter. “Some research indicates that it may be related to a genetic polymorphism in what we call the cytochrome P450 enzyme system, which is how we metabolize marijuana.” But there’s probably more to it than that. For one thing, patients suffering from CVS often compulsively bathe during vomiting episodes, perhaps because taking a hot bath or shower can reduce nausea in the short term. Glatter says it may be the case that hot showers “ameliorate the disequilibrium, and re-adjust the set point of the thermoregulatory system in the hypothalamus.” Another theory, he says, is that “heat dilates blood vessels in the skin and muscle” which in turn diverts blood flow away from the circulation system that supplies the gut and intestines. “When there is less blood flow to the gut and intestines, symptoms of nausea and vomiting are reduced,” adds Glatter. But, he admits, there isn’t a lot of research on this yet, and there’s a lot about it physicians don’t understand.