Emergency departments are seeing a spike in visits owing to a once unusual, highly unpleasant and, in rare cases, potentially life-threatening side effect of chronic cannabis use: severe bouts of vomiting lasting hours, even days.
As pot becomes more potent and more convenient to purchase, emergency doctors are reporting more cases of cannabis hyperemesis syndrome, or CHS, a gastrointestinal condition that can affect people who use cannabis frequently (several times a week, if not daily) over months or years.
In addition to “cyclical” vomiting, other signs include morning nausea, intense abdominal pain and “relief through compulsive hot showers or baths,” Western University researchers
recently wrote.
It’s increasingly affecting teens and young adults, they report. “Yet few people — including many clinicians — know it exists.”
Emergency department visits for CHS increased 13-fold in Ontario after the legalization of recreational cannabis in 2018,
one study found
. While weed’s legalization wasn’t associated with a sudden or gradual change in cases, pot’s commercialization — unlimited number of stores, more products — overlapping with the COVID-19 pandemic, was associated with an immediate bump in rates.
The potency of THC, or tetrahydrocannabinol, the main psychoactive compound in cannabis, is also off the charts, said Western’s Jamie Seabrook, rising from about three per cent in dried cannabis in the 1980s to, according to Health Canada, 15 per cent in 2023. Some strains have as high as 30 per cent THC.
“When I talk to youth, they can easily access strains that are upwards of 25 per cent. And that’s huge,” said Seabrook, a professor in the department of epidemiology and biostatistics, the department of pediatrics and the Brescia School of Food and Nutritional Sciences. The human brain continues to develop up to around age 25, he said. THC exposure over this period has been linked with problems with attention, memory and learning, as well as increased risks of paranoia, psychosis and, more recently, schizophrenia.
Here’s what to know about CHS.
What is cannabinoid hyperemesis syndrome?
CHS was first documented in
2004
by researchers reporting on 10 people from South Australia in whom chronic cannabis use “predated the onset of the cyclical vomiting illness.”
Nine of the 10 “displayed an abnormal washing behaviour during episodes of active illness.”
Reported cases of CHS have since been popping up around the world.
The Ontario study documented 12,866 emergency department visits by 8,140 individuals between January 2014 and June 2021, or pre- and post-legalization. About 35 per cent were aged 19 to 24. Nearly 10 per cent of visits led to hospital admissions. Monthly rates of CHS emergency visits increased from 0.26 per 100,000 population in January 2014, to 3.43 visits per 100,000 population in 2021.
What causes cannabinoid hyperemesis syndrome?
It’s not clear what causes CHS. Cannabinoids bind to cannabinoid receptors in the brain and gastrointestinal tract. One theory is that it may be due to overstimulation of the receptors leading to “issues with your body’s natural control of nausea and vomiting,” according to the Cleveland Clinic.
Paradoxically, low doses of cannabis can help with nausea. “But that’s low doses, and infrequently,” Seabrook said.
“Chronic use substantially increases the risk of nausea.”
What are the symptoms of cannabinoid hyperemesis syndrome?
Telltale symptoms of CHS are severe and persistent vomiting. “Scromiting” is a term that’s been used, a merger of “vomiting” and “screaming,” the Cleveland Clinic reports. “You may have intense pain, which causes you to scream while you vomit.”
Vomiting can lead to dehydration and electrolyte imbalances. Youth can mistakenly think using more pot will help with the nausea and pain, “but it’s actually exacerbating it, because they don’t even realize that they have anything called cannabis hyperemesis syndrome,” Seabrook said.
The big challenge is food and nutrition. “They’re not able to take down food without purging.” Some are mistakenly diagnosed with bulimia nervosa, an eating disorder, “simply because whoever gave that diagnosis wasn’t aware of the extent of cannabis use,” Seabrook said.
With an eating disorder, there’s a body image concern, and people are inducing purging. “Whereas with CHS, they’re not doing it on purpose. It’s the cannabis that’s causing it,” he said.
Others might get worked up for a food intolerance, suggesting “they remove this food, or that.” They might have a CT scan or an MRI, using up “a lot of health-care dollars when these simple basic questions initially could have eliminated a whole bunch of other potential diagnoses,” Seabrook said.
People can get temporary relief from hot baths and showers, but it’s a temporary fix. “When they get out, the symptoms reappear,” Seabrook said.
If left untreated, severe vomiting and dehydration can lead to acute kidney injury. In very rare cases, “it can lead to death, if you are that severely dehydrated and you’re not getting your electrolytes up,” Seabrook said.
Who is at risk?
Most people who develop CHS have used cannabis for several years, Seabrook said. There’s no evidence that, say, a teen who uses high-potency pot one day will immediately get CHS. “It’s long term, and frequency of use,” Seabrook said.
It’s also not clear why not everyone who uses cannabis chronically and frequently develops CHS, though a genetic vulnerability might play a role.
But Canada has one of the highest rates of youth cannabis use in the world, Seabrook said. “The most recent data we have from Canada — and this is kind of alarming — is that about one in five, or 20 per cent of 16- to 19-year-olds have used cannabis in the past month and close to nine per cent daily, or almost every single day,” Seabrook said.
“Potency is a huge factor. But there is also now growing social acceptance (of cannabis) and a lot of youth think there is very little harm associated with its use.”
How does CHS progress?
The first phase is called the prodromal phase, Seabrook said. “Basically, they don’t have classic symptoms at this point, but they’re starting to experience morning nausea; they feel sick to their stomach.”
In phase two — the hyperemetic stage — the severe vomiting kicks in. “It moves beyond just feeling nauseous.” Vomiting and intense pain can last one to two days, or more. Other symptoms include hot flashes, weight loss, high blood pressure, sweating and trembling.
“It’s at this stage two where they start to have baths and showers and they feel like, ‘Whoa, if I crank up this heat, it helps a bit,’” Seabrook said.
The third phase is recovery. Symptoms disappear within days or weeks of stopping cannabis use. “It’s almost 100 per cent. They completely resolve if someone quits cannabis altogether,” Seabrook said.
“But quitting isn’t easy. We always talk about things like addiction: Is cannabis an addiction? If they’re using it every day, maybe it’s more addictive than we originally thought.”
Many youth struggling with mental health turn to cannabis as a coping strategy without recognizing it increases the risk of anxiety and depression.
Some youth may need support stopping. “If you have somebody saying, ‘Look, the only way to stop this is to quit altogether’ that’s very difficult,” Seabrook said.
“A harm reduction approach would involve the use of adolescent medicine or a rehabilitation specialist that can say, ‘I’m going to meet you right where you are at. Let’s see if we can go down to this much use.’ Slowly but surely weaning them off the extent to which they’re using.”
“Lower dose potency is another really good option and slowly trying to reduce the amount and frequency that one uses.”
What else is needed?
More research is needed, including randomized trials to explore different treatment options, greater awareness among healthcare providers — emergency doctors, gastroenterologists and others — and more education in schools and through public health campaigns, Seabrook said.
National Post
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