As cannabis use among youth rises in Canada — and THC potency reaches record highs — emergency departments are seeing a surge in cases of a once-rare condition: cannabis hyperemesis syndrome (CHS).
Characterized by relentless vomiting, abdominal pain and temporary relief through compulsive hot showers or baths, CHS is increasingly affecting adolescents and young adults. Yet few people — including many clinicians — know it exists.
Canada ranks among the highest globally for youth cannabis use, with 43 per cent of 16-19-year-olds reporting use in the past year. Usage peaks among those 20–24 years, with nearly half (48 per cent) reporting past-year use.
This rise in regular, heavy use coincides with a 400 per cent increase in THC potency since the 1980s. Strains with THC levels above 25 per cent are now common. As cannabis becomes more potent and accessible, clinicians are seeing more cases of CHS, a condition virtually unheard of before 2004.
CHS unfolds in three phases:
Prodromal phase: Nausea and early morning discomfort begin. Users increase cannabis consumption, thinking it will relieve symptoms.
Hyperemetic phase: Intense vomiting, dehydration and abdominal pain follow. Hot showers or baths provide temporary relief — a hallmark of CHS.
Recovery phase: Symptoms resolve after stopping cannabis entirely.
Diagnosis is often delayed. One reason is because CHS mimics conditions like gastroenteritis or eating disorders, leading to costly CT scans, MRIs and gastric emptying tests. One telltale sign — compulsive hot bathing — is frequently overlooked, despite its strong diagnostic value.
Youth face unique risks. The brain continues to develop until about age 25, and THC exposure during this critical window can impair cognitive functions like memory, learning and emotional regulation. Heavy cannabis use is associated with heightened risks of anxiety, depression, psychosis and self-harm.
Edit, the link in the article goes to this study:
https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2796355
Results There were 12 866 ED visits for CHS from 8140 individuals during the study. Overall, the mean (SD) age was 27.4 (10.5) years, with 2834 individuals (34.8%) aged 19 to 24 years, 4163 (51.5%) females, and 1353 individuals (16.6%) with a mental health ED visit or hospitalization in the 2 years before their first CHS ED visit. Nearly 10% of visits (1135 visits [8.8%]) led to hospital admissions. Monthly rates of CHS ED visits increased 13-fold during the 7.5-year study period, from 0.26 visits per 100 000 population in January 2014 to 3.43 visits per 100 000 population in June 2021. Legalization was not associated with an immediate or gradual change in rates of ED visits for CHS; however, commercialization during the COVID-19 pandemic period was associated with an immediate increase in rates of CHS ED visits (incidence rate ratio [IRR], 1.49; 95% CI, 1.31-1.70). During commercialization, rates of CHS ED visits increased more in women (IRR, 1.49; 95% CI, 1.16-1.92) and individuals older than the legal age of cannabis purchase (eg, age 19-24 years: IRR, 1.60; 95% CI, 1.19-2.16) than men (IRR, 1.08; 95% CI, 0.85-1.37) and individuals younger than the legal age of purchase (IRR, 0.78; 95% CI, 0.42-1.45).
You didn't read any of it.
The safest in a group of harmful things doesn't make it safe!
Here's what the research says:
"The review of published research shows that cannabis use may impair immune function in many instances and thereby exerts an impact on viral infections including human immune deficiency virus (HIV), hepatitis C infection (HCV), and human T-cell lymphotropic type I and II virus (HTLV-I/II)." Maggirwar SB, Khalsa JH. The Link between Cannabis Use, Immune System, and Viral Infections. Viruses. 2021;13(6):1099. Published 2021 Jun 9. doi:10.3390/v13061099
Again, more studies to help you:
"This adds to the substantial evidence base that has previously identified cannabis use to associate with increased risk of schizophrenia, by suggesting that the relationship is causal. Such robust evidence may inform public health messages about cannabis use, especially regarding its potential mental health consequences." Vaucher J, Keating BJ, Lasserre AM, et al. Cannabis use and risk of schizophrenia: a Mendelian randomization study. Mol Psychiatry. 2018;23(5):1287-1292. doi:10.1038/mp.2016.252
"To date, the research on the impact of its use has largely been epidemiological in nature and has consistently found that cannabis use is associated with schizophrenia outcomes later in life, even after controlling for several confounding factors." Casadio P, Fernandes C, Murray RM, Di Forti M. Cannabis use in young people: the risk for schizophrenia. Neurosci Biobehav Rev. 2011;35(8):1779-1787. doi:10.1016/j.neubiorev.2011.04.007
There are dozens more, if you need them.
I truly appreciate the time you took to read the studies. I respect that, however, the personal attacks are unwarranted, and you're more than welcome to debate the experts who've compiled the data, if you like.
Let's take things one at a time, but it should also be noted that much of the research cited are medicinal users of cannabis (including those prescribed by doctors), not recreational, which is what the actual OP is about. You avoided touching on any of those from the long list by the Canadian Centre on Substance Use and Addiction.
You conveniently left out the parts before that:
"Research suggests a link between cannabis, immune function, and viral infections. Cannabis use may be associated with adverse effects on immune function and, thereby, increase the risk of acquiring or transmitting infections such as HIV and HCV. "
The part you bring up has to do with viral progression, which is different. And the fact that more research is needed in this area (per the study), doesn't clear cannabis from harm.
The benefits of increased appetite in someone who is dying is great! Too bad, that has no relevance to the general population, so the risks outweigh the benefits.
That doesn't appear to be the study I linked, but we agree, increased risks.
But why did you skip the most important parts of the conclusion?
"Neuroimaging studies show the detrimental effect of cannabis on brain morphology, especially adolescent brains. "
"...there is still more harm from cannabis than benefits, and adolescent cannabis usage should be discouraged at all costs."
That's pretty damning for something considered safe, wouldn't you agree?
Trials... therapeutic CBD... that sounds considerably different from recreational use outside of a medical setting, no? Like the type of use they would like to see discouraged "at all costs".
Anyway, the study I linked is: https://pmc.ncbi.nlm.nih.gov/articles/PMC5984096/
"In summary, a genetic approach—representing an alternative to assessing causality when a randomized controlled trial would be unethical—strongly supports the hypothesis that use of cannabis is causally related to risk of schizophrenia."
This was my oversight, and I apologize for that.
That review paper was quite outdated, and the same author has a much more recent study available: https://pmc.ncbi.nlm.nih.gov/articles/PMC7646282/
"In conclusion, our findings confirm previous evidence of the harmful effect on mental health of daily use of cannabis, especially of high-potency types. Importantly, they indicate for the first time how cannabis use affects the incidence of psychotic disorder. Therefore, it is of public health importance to acknowledge alongside the potential medicinal properties of some cannabis constituents the potential adverse effects that are associated with daily cannabis use, especially of high-potency varieties."
I hope that covers it. There seems to be more than enough evidence to suggest that cannabis is not safe, even for being the "safest recreational drug".
Edit: grammar/spelling.
I'm sorry that your mental health is in such a bad state.
I read in your other comment that you've been a daily cannabis user for decades, and now I can understand your aggressive defense of the drug, and your unhinged behaviour.
I wish you said that sooner. Your agenda is to defend your addiction, so there was never an honest discussion here.
It was fun. Get some help.
I'm not upset about anything. The studies speak for themselves.
No, that extra bit of information gives me context for understanding where you're coming from.
You were never going to be receptive of the facts, because they'd contradict the story you've been telling yourself about the "safest" harmful recreational drug.
I just never realized that was your motivation until just now.
Who's arguing about coffee, anyway?
This feels like playing chess with a pigeon, TBH.
Ok, buddy. "You win."