What Is Cannabinoid Hyperemesis Syndrome (CHS)?

What Causes CHS?

There are three main theories for what might cause CHS:

1. Hypothalamic Theory

The first theory is that frequent exposure to cannabinoids like THC (tetrahydrocannabinol) causes a shift in the endocannabinoid system’s (ECS) activity in the hypothalamus. The hypothalamus is the region of the brain responsible for regulating stress and temperature.

When these receptors become dysfunctional (particularly the CB1 receptors), it could cause a change in the thermoregulatory set-point for body temperature and affect the nearby nausea center in the brain. This would result in a reduced body temperature and could explain why taking a hot shower is so effective for mitigating symptoms.

CBD has been shown to increase the expression of CB1 receptors in this part of the brain, which could mean this cannabinoid is a contributing factor to the disorder. It’s THC that activates these receptors, however.

2. Cannabinoid Build-Up Theory

The second theory suggests the symptoms of CHS are caused by a toxic dose of cannabinoids.

When we take any substance into the body, it needs to be cleared by the liver and the kidneys. If we continually take more of the substance before it’s completely eliminated from the body, it can start to build up in the bloodstream.

We may not notice the increased concentration of cannabinoids for a long time, but eventually, levels will reach a toxic threshold — which may cause the symptoms associated with CHS.

Additionally, cannabinoids are stored in fat. Once we start losing weight due to frequent vomiting caused by CHS, the loss of fat will release even more cannabinoids into the body — causing the condition to worsen.

3. TRPV1 Theory

The final theory involves a separate type of receptors many cannabinoids interact with called TRPV1 or the vanilloid receptors.

These receptors are responsible for the “hot” sensation experienced when eating spicy foods, and they play a role in the transmission of pain, movement of the gastrointestinal system, and temperature regulation.

Some cannabinoids have been shown to reduce the sensitivity of the TRPV1 receptors. So it’s believed that frequent exposure to these cannabinoids may cause downregulation of the TRPV1 receptors, leading to the symptoms associated with the condition.

This explains the compulsive need to take hot showers to normalize TRPV1 activity and alleviate symptoms.

It could also explain why other TRPV1 agonists, such as capsaicin ointments, are so reliable for providing relief from the condition as well.

Cannabinoids & The Endocannabinoid System

There are many active ingredients in the cannabis plant. The primary constituents are THC (tetrahydrocannabinol) and CBD (cannabidiol).

Both of these active ingredients work through a series of receptors known collectively as the endocannabinoid system (ECS).

The ECS is responsible for regulating neurological, gastrointestinal, renal, cardiovascular, and immune functions. It’s intimately involved in monitoring and maintaining a balance of these critical systems.

Every living organism on earth has an ECS. Hormone-like compounds called endocannabinoids are made by the body to transmit messages between the ECS receptors. We need this system to survive — without it, we lose our ability to maintain balance (homeostasis).

Cannabinoids from the cannabis plant, such as THC, CBC, CBN, and CBD, have a similar shape and structure to our endocannabinoids. This allows them to interact with the ECS by activating or altering the receptors. This is what gives cannabis its health-promoting benefits.

CBD, for example, increases the activity of the ECS in the brain — which results in an inhibition of pain, inhibition of nausea, and reduced electrical activity associated with anxiety.

THC also increases ECS activity in the brain, but in a different way. It stimulates the CB1 endocannabinoid receptors, which in turn control serotonin. The shift in serotonin levels is what makes users feel high when they use marijuana products.

Which Cannabinoids Contribute to CHS?

It’s unclear which cannabinoids directly cause the symptoms associated with CHS. Current evidence points the finger at delta 9 THC — which is the primary activator of the endocannabinoid receptors.

However, other cannabinoids may be involved as well:

Can CBD Cause CHS?

The primary cause of CHS is THC found exclusively in marijuana products.

It’s unclear whether CBD (cannabidiol) can cause CHS too, but early evidence suggests it may contribute to existing CHS symptoms. CBD has been shown to enhance the expression of CB1 receptors in the hypothalamus and amplifies the hypothermic effects caused by THC [5]. This effect could increase the progression of CHS through the hypothalamus theory highlighted above.

Additional studies have shown that lower doses of CBD are antiemetic, but higher doses can actually cause vomiting [6]. This would support the idea that CBD can cause CHS through the cannabinoid buildup theory mentioned above.

This means if you’re experiencing CHS, you should avoid taking any cannabis products — including non-psychoactive hemp supplements.

Researchers are still seeking to understand which cannabinoids can cause the condition and which ones can’t.

Can Delta 8 THC Cause CHS?

There are various forms of THC — delta 9 THC, delta 8 THC, delta 10 THC, delta 7 THC, and more.

The most common form, by far, is the delta 9 isomer — which has already been confirmed to be one of the primary causes of CHS.

So what about the less abundant delta 8 THC isomer?

There’s virtually no research on how delta 8 THC may affect people with CHS, and there aren’t enough users to find a pattern in people with symptoms of CHS.

With that said, delta 8 THC is still THC — it affects the same receptors, and despite having some differences in how it affects the body, it still pushes the same receptors and causes the same effects. Delta 8 THC likely has the same or similar effects on the ECS that cause the condition of CHS.

Can CBG Cause CHS?

CBG (cannabigerol) has been shown to reverse some of the anti-nausea effects of THC as the CB1 receptor sites [4]. Some preliminary studies suggest this cannabinoid may be a contributing factor in the pathophysiology of CHS.

How is CHS Diagnosed?

CHS is a syndrome — which means it’s a set of symptoms that often accompany each other but may not share the same underlying cause.

It’s much harder to diagnose a syndrome than a disease, which has a specific, identifiable cause.

As a result, diagnosing CHS is done by ruling out other potential causes — rather than by testing for the disorder itself.

This condition is still not well understood and was only first identified in 2004 [1]. As cannabis becomes legal in more parts of the world, rates of this condition are increasing. CHS currently accounts for around 6% of emergency room visits for vomiting. As a result, the medical community is getting much better at diagnosing it. 

Doctors may request the following tests to rule out other potential causes:

• Blood tests — to check for anemia, infection, or leukemia
• Electrolyte test — to check for signs of dehydration or hyperkalemia
• Liver function tests — to check for signs of liver disease
• Pregnancy test — to assess the potential for symptoms caused by morning sickness
• Urine tests — to check for signs of drug use, infection, or kidney disease
• X-rays or ultrasound of the abdomen — to check for physical causes of pain & vomiting
• Head CT scan or fMRI — to check for other neurological disorders that may explain symptoms

They’ll also want to know about the last time you used marijuana or other cannabis products (including delta 8 THC or CBD) and how often and for how long you’ve used them. They may also ask about the dose or request you bring packaging for the products you’re using in the clinic so they can take a look.

They will also ask about other medications, family history, and whether or not you’ve been sexually active.

How is CHS Treated?

The best treatment for this condition is to stop using all marijuana products.

Researchers are still trying to understand this condition in more detail, but from the data we have available right now, it appears this condition is permanent. Meaning that patients who suffer from CHS will experience the same symptoms all over again if they use marijuana products again — even after taking an extended break from marijuana.

The rest of the treatment involves managing symptoms and preventing the more dangerous side effects associated with dehydration and electrolyte imbalance that can result from frequent vomiting.

Treatment for CHS may include:

• IV fluid (for dehydration)
• Antiemetic medications (medications that prevent vomiting)
• Pain medications
• Proton pump inhibitors
• Frequent hot showers
• Anti-anxiety medications (such as benzodiazepines)
• Herbal medicines (such as ginger or topical cayenne ointments)
• Dopamine antagonists
• Stopping all opioid medications

Summary: What is CHS?

CHS stands for cannabinoid hyperemesis syndrome. It’s sometimes referred to as cannabis hyperemesis syndrome — both of these terms mean the same thing. 

Over time, the body becomes resistant to the effects of the active ingredients in the plant. When marijuana is used, it leads to a dramatic increase in nausea and vomiting and can cause abdominal pain, dehydration, dizziness, and a variety of other symptoms.

The only known treatment for CHS is to stop using marijuana. Upon stopping, symptoms usually go away within two days but can take several months in some people.

This condition is still very poorly understood, and we still don’t know exactly what causes it or which cannabinoids are involved.

References

1. Chu, F., & Cascella, M. (2019). Cannabinoid hyperemesis syndrome.
2. Sorensen, C. J., DeSanto, K., Borgelt, L., Phillips, K. T., & Monte, A. A. (2017). Cannabinoid hyperemesis syndrome: diagnosis, pathophysiology, and treatment—a systematic review. Journal of Medical Toxicology, 13(1), 71-87.
3. Habboushe, J., Rubin, A., Liu, H., & Hoffman, R. S. (2018). The prevalence of cannabinoid hyperemesis syndrome among regular marijuana smokers in an urban public hospital. Basic & clinical pharmacology & toxicology, 122(6), 660-662.
4. Rock, E. M., Goodwin, J. M., Limebeer, C. L., Breuer, A., Pertwee, R. G., Mechoulam, R., & Parker, L. A. (2011). Interaction between non-psychotropic cannabinoids in marihuana: effect of cannabigerol (CBG) on the anti-nausea or antiemetic effects of cannabidiol (CBD) in rats and shrews. Psychopharmacology, 215(3), 505-512.
5. Hayakawa, K., Mishima, K., Hazekawa, M., Sano, K., Irie, K., Orito, K., … & Fujiwara, M. (2008). Cannabidiol potentiates pharmacological effects of Δ9-tetrahydrocannabinol via CB1 receptor-dependent mechanism. Brain Research, 1188, 157-164.
6. Parker, L. A., Kwiatkowska, M., Burton, P., & Mechoulam, R. (2004). Effect of cannabinoids on lithium-induced vomiting in the Suncus murinus (house musk shrew). Psychopharmacology, 171(2), 156-161.