Until now, cases of CHS were presumed to be incredibly rare. But some recent evidence indicates cases could be on the rise, and a new study from emergency clinicians at New York University Langone suggests the syndrome may affect far more people than initially thought. The worst part may be that patients have no idea that cannabis may be causing their symptoms, since paradoxically, weed is sometimes used to treat nausea.
"This is something that's poorly understood that doctors don't know about," Joseph Habboushe, an assistant professor at NYU Langone and the lead author on the paper, told Business Insider. "It could affect millions."
The first study to give a sense of how many people this may affect
The stories of Mrs. X and the others in the 2004 study didn't cause widespread concern among medical professionals. Marijuana was still largely illegal at the time, for one thing. And the symptoms appeared to disappear for good as soon as the patients stopped using the drug.
Plus, Mrs. X's story was part of a series of case reports, a type of paper that doesn't involve rigorous research parameters; it merely describes the symptoms of one or several people.
The scientists behind the latest study, published in the journal Basic and Clinical Pharmacology and Toxicology, looked into CHS by examining a large sample of adults admitted to an emergency room in New York City. The researchers surveyed thousands of patients in an attempt to find only those who used marijuana frequently — at least 20 days per month — and ended up with 155 people who met their criteria. All of those individuals smoked nearly every day or multiple times a day, often for five years or more.
Among those patients, roughly a third had symptoms that qualified them for a diagnosis with CHS.
That's a big number, Habboushe said — far bigger than he anticipated.
"Some of my colleagues and I had some idea that this might be more common than initial studies suggested, but we were still pretty surprised," he said.
Given that figure, Habboushe and his colleagues estimated that as many as 2 million US adults could be affected by the syndrome. Still, given the small sample size, it may be too early to say how many people could really develop CHS.