Cannabis hyperemesis syndrome (CHS): symptoms, causes and more

What is CHS?

Cannabinoid hyperemesis syndrome (CHS) is a rare but serious reaction to the regular use of cannabis. It occurs mainly in people who regularly consume high amounts over a long period of time. The main symptoms include severe vomiting, unbearable abdominal pain and persistent nausea. Although cannabis is often considered relatively harmless, in some cases its use can lead to this syndrome. Interestingly, CHS is often not immediately recognised as the symptoms can be confused with other health problems. The only known way to alleviate the symptoms is to stop using cannabis immediately, which usually causes the symptoms to subside quickly.

The symptoms of CHS

The symptoms of CHS can feel like a severe gastrointestinal illness and often occur in episodes. The most common signs include

• Repeated vomiting: constant vomiting is the most noticeable symptom and can last for long periods of time.

• Severe abdominal pain: This often occurs in the upper abdominal area and can be very uncomfortable.

• Persistent nausea: Even after vomiting, the nausea persists, making the situation even more difficult for those affected.

• Cyclical patterns: Symptoms often occur in phases, alternating between relatively symptom-free periods and intense periods of illness.

Another characteristic feature of CHS is that many sufferers report experiencing short-term relief from hot showers or baths. This effect, known as "water therapy", is not fully explained but provides at least temporary relief for many sufferers.

The symptoms can severely affect quality of life, which is why it is crucial to stop using cannabis immediately in order to achieve improvement. In the next section, we explain what to do about CHS.

What to do about CHS?

The most effective treatment for CHS is to stop using cannabis immediately. Once use is stopped, symptoms usually begin to disappear within days to weeks. There is no specific medication that directly cures CHS, but symptoms can be alleviated with various measures:

• Hydration: as severe vomiting and nausea can lead to dehydration, it is important to drink plenty of fluids. Electrolyte solutions or intravenous fluids in a hospital setting are often necessary to make up for fluid loss.

• Symptomatic treatment: Doctors may prescribe medication to relieve the nausea and break the vomiting cycle. In some cases, painkillers may also be used to relieve abdominal cramps.

• Water therapy: As mentioned above, many sufferers report that hot showers or baths relieve the discomfort in the short term, although this is not a long-term solution, it can provide temporary relief.

In the long term, there is no known "cure" for CHS other than abstaining from cannabis. Once symptoms have subsided, cannabis use should be avoided at all costs to prevent relapse. In some cases, it may be useful to address the underlying psychological or physical causes of long-term cannabis use.

How common is CHS?

Cannabinoid hyperemesis syndrome (CHS) is relatively rare, but the exact incidence is difficult to determine as many cases are not properly diagnosed. Studies show that CHS occurs mainly in long-term and regular users of cannabis who consume high amounts over many years. It is estimated that around 2 to 5% of chronic cannabis users may be affected by this syndrome.

The problem with estimating the incidence is that the symptoms of CHS are often confused with other conditions such as gastrointestinal disorders or gastritis. Many sufferers do not seek medical help until the symptoms have been present for a long time, which delays a proper diagnosis. In addition, CHS is only recognised as a separate syndrome relatively late, which could also lead to an underestimation of the incidence.

As cannabis becomes increasingly legalised in many countries, CHS may be recognised more often as more people become aware of the potential health consequences. It is important that doctors and users are aware that chronic cannabis use can in some cases lead to this extremely unpleasant but treatable condition.

What causes CHS?

The exact cause of CHS is not yet fully understood, but there is some evidence that points to the interaction between cannabis and the body's endocannabinoid system. Cannabis affects this system, which is responsible for many physiological processes such as pain, appetite and digestion. Long-term use appears to disrupt this system, possibly triggering the vomiting and other symptoms of CHS.

Another factor could be the development of tolerance. In chronic users, the body increasingly adapts to the effects of THC (the psychoactive component of cannabis), consuming larger and larger amounts to achieve the same effect. This adaptation could eventually lead to a negative reaction in the body, where the nervous and digestive systems become overloaded, resulting in the symptoms described.

It is also thought that genetic factors could play a role. Not every consumer develops CHS, suggesting that there are certain predispositions that could increase the risk. However, these factors have not yet been fully researched.

The best way to prevent the onset of CHS is to refrain from excessive cannabis use, especially over a long period of time.

Which cannabinoids contribute to CHS?

Cannabinoid hyperemesis syndrome (CHS) is primarily associated with the psychoactive compound tetrahydrocannabinol. THC affects the body's endocannabinoid system and can paradoxically lead to symptoms such as nausea and vomiting with long-term, high-dose use.

In addition to THC, other cannabinoids may also play a role:

• Delta-8-THC: a chemical variant of THC with similar effects. Initial indications suggest that delta-8-THC can also trigger CHS, but research is still in its infancy.

• CBG (cannabigerol): A non-psychoactive cannabinoid that serves as a precursor for other cannabinoids. The involvement of CBG in CHS has not yet been proven, but is increasingly being investigated.

There are currently many indications that products with a high THC content in particular increase the risk of CHS - especially with regular and intensive use. There are still many unanswered questions, but research into CHS and its connection to various cannabinoids is gaining momentum.

Can delta-8-THC cause CHS?

Delta-8-THC is a chemical variant of the better-known delta-9-THC - the compound classically associated with the cannabis "high." Although delta-8-THC is considered a milder and "legal" offshoot, it is also psychoactive and interacts with the same receptors in the brain and digestive system.

In recent years, an increasing number of reports have emerged in which users of delta-8-THC complain of symptoms similar to those of CHS: recurring nausea, severe vomiting and a strong malaise that can be alleviated by hot showers. Although there are currently no comprehensive studies specifically on delta-8-THC and CHS, it is reasonable to assume that delta-8-THC can also trigger CHS, especially with regular use.

Can CBG also cause CHS?

CBG (cannabigerol) is a non-psychoactive cannabinoid that is considered a precursor to THC and CBD. It is often valued for its anti-inflammatory effect - but the question of whether CBG can also trigger CHS has not yet been clearly answered.

There is currently no scientific evidence that CBG is directly linked to CHS. The known cases relate almost exclusively to THC. However, as CBG is often consumed together with other cannabinoids, an influence cannot be completely ruled out.

When was CHS first discovered?

Cannabinoid hyperemesis syndrome (CHS) was first described in 2004 in a study by Dr Michael A. Allen and his colleagues, who documented a series of patients who were suddenly admitted to hospital with repeated vomiting and severe abdominal pain after years of intensive cannabis use. At that time, the symptoms were known, but the link with cannabis was not yet recognised.

Initially, CHS was confused with other gastrointestinal disorders, which is why it often took years before a diagnosis was made. Only with increasing research and more cases did it become clear that CHS is a specific reaction to chronic cannabis use. It is particularly noteworthy that the symptoms usually disappear completely after cannabis is discontinued - an indication that the cause really lies in the consumption.

Summary: What is CHS?

Cannabinoid hyperemesis syndrome (CHS) is a rare but serious reaction to the regular use of cannabis, which mainly occurs in long-term users. The most important points summarised:

• Severe symptoms: CHS mainly manifests as repeated vomiting, nausea and severe abdominal pain.

• Cyclical course: Symptoms occur in phases, often accompanied by short-term relief from hot showers or baths.

• Cause: The main cause of CHS appears to be THC, especially with long-term, intensive use.

• Treatment: The most effective way to treat CHS is to stop using cannabis immediately. Once use is stopped, the symptoms usually disappear.

• Research: Although CHS was first described in 2004, research is still ongoing and many questions remain unanswered.

It is important to be aware of the potential risks of cannabis use, especially if it is done over a long period of time and in high quantities. Anyone who notices symptoms such as constant vomiting or abdominal pain after use should stop use immediately and seek medical help.