What You Need to Know About This Marijuana-Related Illness

Hospitals in states where marijuana has been legalized are seeing a slight increase in patients exhibiting symptoms of a marijuana-related illness known as cannabinoid hyperemesis syndrome (CHS). But the condition isn't new or particularly common, contrary to the recent surge of media reports on the illness.


CHS is believed to be tied to heavy, long-term cannabis use, and it's characterized by symptoms such as abdominal pain, nausea, and vomiting. It was first documented by Australian researchers in a 2004 study published in the journal Gut. Their report looked at 19 patients, who were "identified with chronic cannabis abuse and a cyclical vomiting illness" and found, in all but seven cases, symptoms stopped when patients ceased cannabis use.

Symptoms also seem to dissipate when CHS sufferers take hot showers, which is apparently one way that some doctors are able to identify the illness.

Dr. Kennon Heard, a toxicologist at the University of Colorado School of Medicine, told Colorado Public Radio that not much is known about CHS or the type of marijuana users that are most likely to develop the condition.

"Based on the fact that it's usually seen in people who are frequent heavy users, what we see with other drugs is frequently the nervous system changes in response to that constant stimulation from the active chemicals in the drug, something like you'd see from someone who becomes dependent on opioids or alcohol for example, and as you are exposed to the drug or heavy amounts of the drug for a long period of time, your body makes adaptations to that. And then those of adaptations can likely cause the effects we are seeing. Now we don't have any real good science to explain what exactly those adaptations are; that's very much a 30,000-foot view and we'd like to get some more information because it will help us understand the cause of this disease and potentially even some other therapeutic ways that cannabinoids could be used."

Part of the reason there's such limited information about CHS is that there are few reported cases of the illness. Heard said that "CHS is a relatively uncommon condition" in a 2015 study published in the journal Academic Emergency Medicine, even as he noted that cases have doubled in Colorado since 2009. Prior to legalization, researchers identified 41 cases of CHS out of about 113,000 emergency room visits. After the state legalized, hospitals reported 87 cases of CHS out of about 125,000 visits.


On the other hand, the illness could be more common than current estimates would have you believe because CHS is not well-known in the national medical community, according to experts.

The good news is that CHS is not life-threatening and generally goes away as long as you stop smoking cannabis.