Cannabis hyperemesis syndrome (CHS) is a newly recognized condition causing severe nausea and vomiting in long-term cannabis users.
Key facts about CHS:
- Repeated, uncontrollable vomiting is the main symptom
- Occurs in long-term heavy cannabis users
- Exact cause is unknown, but likely involves cannabis effects on brain receptors
- Stopping cannabis use is the only definitive cure
- No firmly established medical treatments, but several options can provide symptom relief
CHS was only officially classified in 2016, but emerging research is documenting this paradoxical effect of cannabis in some chronic users.
Source: Med Princ Pract. 2022
What is Cannabis Hyperemesis Syndrome (CHS)?
The main feature of CHS is severe, persistent nausea and vomiting.
Vomiting typically occurs in repeated episodes over the course of hours to days.
Symptoms can be extremely debilitating, leading to frequent emergency room visits and interference with daily life.
CHS occurs in long-term, heavy cannabis users.
The vomiting is caused by the cannabis use itself, even though cannabis is better known for reducing nausea and improving appetite.
Researchers estimate CHS may affect up to 2 million regular cannabis users in the United States.
Diagnosing CHS can be tricky because the severe vomiting resembles other conditions like cyclic vomiting syndrome, bulimia, and psychogenic vomiting.
But a diagnosis can be made based on the individual’s cannabis use history along with the pattern, timing and severity of symptoms.
CHS follows three phases:
Prodromal phase – mild nausea and abdominal discomfort that precedes vomiting episodes. This can go on for months or years.
Hyperemesis phase – the acute vomiting phase, lasting less than 1 week. Profuse, uncontrollable vomiting occurs numerous times per day. This leads to emergency care.
Recovery phase – vomiting ends and appetite returns to normal until the next episode occurs.
What Causes Cannabis Hyperemesis Syndrome?
The exact mechanisms behind CHS are still unknown.
However, research points to the impact of long-term, heavy cannabis use on the endocannabinoid system – the network of brain receptors that interact with cannabis compounds like THC and CBD.
Three leading theories for what goes wrong:
- Imbalance in cannabinoid receptors in the gut and brain. The receptors normally regulate nausea and vomiting, but chronic overstimulation from cannabis could make the system go haywire.
- Buildup of cannabis toxins. THC and other cannabis compounds are fat-soluble and may accumulate over time, eventually reaching a toxicity threshold.
- Genetic differences in metabolizing cannabis. Variations in enzymes that break down cannabis may predispose certain people to CHS.
Interestingly, cannabis formulations, strains or methods don’t seem to make a difference – CHS occurs with smoked, vaped, and edible cannabis.
This points to a cumulative toxicity effect regardless of how cannabis compounds enter the body.
Treatment Options for Cannabis Hyperemesis Syndrome
Unsurprisingly, the only definite “cure” for the vomiting caused by CHS is to stop cannabis use completely.
But this is often easier said than done.
For people unable or unwilling to quit right away, a few medical therapies can provide some relief from the severe nausea and vomiting:
- Hot showers – This is a classic self-treatment used by CHS patients, though doctors still don’t know exactly why it helps. The relaxation and distraction of a hot shower may play a role.
- Capsaicin cream – Capsaicin is the active component of hot peppers. Creams applied to the abdomen may work by distracting the brain from the stomach discomfort.
- Antipsychotic drugs – Older medications like haloperidol directly block the brain’s vomiting reflex.
- Sedatives – Anti-anxiety drugs or benzodiazepines can help control nausea and calm the vomiting response.
While these can temporarily help manage an episode of CHS vomiting, quitting cannabis altogether is still the ultimate treatment.
With cessation of use, CHS symptoms typically resolve within days to months.
Recurrence is common with re-exposure.
Preventing Cannabis Hyperemesis Syndrome
Because CHS is linked to heavy, long-term cannabis intake, it stands to reason that limiting cannabis consumption should reduce the risk.
However, we still lack research on the precise thresholds needed to trigger CHS.
Based on clinical cases, regular cannabis use for longer than 1-2 years seems to increase the risk, especially with daily high-potency forms like waxes and oils.
High doses of oral medical cannabis may also contribute.
For frequent cannabis users, be alert for potential early symptoms like mild stomachaches and nausea.
These can progress to vomiting over time. Taking breaks from cannabis may help reset the endocannabinoid system and avoid toxicity.
Of course, abstaining from cannabis completely eliminates the risk of CHS.
But for those who use regularly, monitoring dosage and avoiding compulsive overuse offers a sensible harm reduction approach.
The Big Picture on CHS
Cannabis hyperemesis syndrome highlights important new medical insights about the risks of heavy cannabis use over time.
While cannabis offers therapeutic benefits for some conditions, we must also acknowledge the potential for adverse effects from overactivation of the endocannabinoid system.
For the millions of regular cannabis consumers, CHS remains an obscure but very real danger – one that both patients and healthcare providers need to recognize.
Only through greater awareness and education can we work to prevent, identify and treat this disruptive syndrome appropriately.
References
- Study: A systematic review on cannabis hyperemesis syndrome and its management options
- Authors: Helen Senderovich et al. (2022)
