In a Gallup survey from 1969, 12% of respondents were in favor of legalizing marijuana; in 2023, though, that number is now up to 70%. Moreover, 38 of the 50 U.S. states have already legalized medical marijuana use while 23 have legalized recreational use, and there are estimates that around 18% of the American population has used it at least once. Though generally safe when used in moderation, there is evidence of several cannabis-related disorders that may be a concern for some people. One that shouldn’t be overlooked is cannabinoid hyperemesis syndrome.

What Is Cannabis and How Does it Work?

Also known by the informal name marijuana, cannabis is a psychoactive drug that is derived from various parts of the Cannabis sativa plant. This plant has been cultivated and used by many different cultures over thousands of years of human history. For many of these cultures, the plant was valued both for practical reasons (such as hemp) and because of its psychoactive effects that can induce a sense of euphoria. Today there are several ways to use cannabis, including smoking, vaping, and consumption.

What makes the cannabis plant unique is the high concentration of compounds known as cannabinoids; the two most well-known examples are tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is the primary psychoactive compound in cannabis, responsible for the “high” sensation that drives most use. It interacts with cannabinoid receptors in the brain that are associated with pleasure, memory, thinking, coordination, and time perception. CBD, by contrast, doesn’t have psychoactive effects and is typically used for therapeutic reasons such as reducing inflammation and some kinds of pain.

When cannabis is consumed, whether by smoking, vaping, or ingesting, the THC and other cannabinoids are absorbed into the bloodstream and are distributed around the body and especially in the brain. Once in the brain, they bind to and temporarily activate the cannabinoid receptors located on our neurons. During this time, some of a person’s normal neural functions are interrupted in a way that leads to the sensations normally associated with cannabis. How long these sensations last depends on dosage and a number of other factors.

What is Cannabinoid Hyperemesis Syndrome?

Even though the psychoactive effects of cannabinoids on the nervous system are temporary and generally safe, there is some evidence that long-term use may cause health problems for some people. Cannabinoid hyperemesis syndrome (CHS) is an example of a relatively rare condition that can develop in people who are regular users of cannabis. Since this condition was only first identified in 2004, it is likely underreported in medical literature; yet there is evidence that it affects as many as 30% of regular marijuana users.

As a syndrome, CHS is defined by the symptoms people tend to experience. Since everyone is different, the length of time and quantity of cannabis products needed to trigger these symptoms is unique to the individual. However, these symptoms tend to manifest in three phases:

  • Prodromal phase: Lasting for months or possibly years, this phase refers to the onset of the earliest signs and symptoms of the syndrome. These symptoms can include nausea in the early morning, abdominal pain, sweating, and increased thirst; there are also usually feelings of anxiety and fear related to vomiting.
  • Hyperemetic phase: In this characteristic phase of the syndrome, a person may experience uncontrollable and severe vomiting along with stomach pain and often dehydration. Vomiting is one of the main symptoms of CHS, but it may also be a symptom of cyclic vomiting syndrome (CVS), a different condition that happens to present in a very similar way.
  • Recovery phase: The final recovery phase generally only occurs if one’s cannabis use is stopped for a time. Once stopped, the symptoms subside within a few days to weeks; however, the symptoms can return if the patient begins to use cannabis again.

The exact cause of cannabis hyperemesis syndrome is not fully understood, but it is believed to arise when chronic marijuana use leads to the dysregulation of the endocannabinoid system. This doesn’t happen to everyone who uses cannabis, but in some people the binding of cannabinoids disrupts neural activity at the same time as digestive system function. It is these disruptions that lead to the described symptoms.

How Is Cannabinoid Hyperemesis Syndrome Diagnosed?

Given the widespread use of cannabis and the ongoing efforts toward full legalization, there are many people who may develop or eventually develop CHS. To diagnose the condition, clinicians typically use several methods that are aimed at identifying the symptoms (primarily related to vomiting) and ruling out other possible causes; this typically involves at least a physical exam and a look at medical history. Since 2016, there are three criteria for a CHS diagnosis that must be present for a period of at least three months:

  1. regular episodes of vomiting
  2. symptoms only occur after long-term marijuana use
  3. the symptoms resolve after stopping the use of marijuana

Since nausea and vomiting are the central symptoms of CHS, much of the diagnostic process is ultimately about ruling out other gastrointestinal causes. For this reason, imaging tests like an ultrasound or CT scan may be used to investigate other aspects of the patient’s digestive health. Blood tests may also be used to identify an electrolyte imbalance or other signs of dehydration.

Treatment of Cannabinoid Hyperemesis Syndrome

Because CHS is so directly related to the use of cannabis, a main component of treatment is simply ceasing to use it. In most cases, a cessation will lead to a resolution of the symptoms within days. For some people, though, it may take longer for a resolution or the additional symptoms are just too disruptive. This is why there are several other treatment options available:

  • Fluid intake: Since vomiting is one of the main symptoms of CHS, dehydration is a risk due to loss of fluids. Oral rehydration is normal for mild cases, but more severe symptoms may require the use of IV fluids.
  • Medication: Antiemetic medications are often prescribed to reduce nausea and control severe vomiting; examples include ondansetron, promethazine, or metoclopramide. There are also some antipsychotic medications and other drugs used for mental health that may be prescribed; examples include haloperidol and benzodiazepine.
  • Topical cream: Some patients with CHS may also find relief from symptoms of nausea by applying capsaicin cream topically to the abdomen. Capsaicin, the active component in chili peppers, is believed to desensitize some of the receptors involved in the sensations of nausea and abdominal pain.
  • Bathing in hot water: Taking a hot shower or hot bath is a common way to self-manage some of the symptoms of CHS. This is not universally effective, and it has the potential to lead to compulsive bathing, but there is some evidence that it can help.

Contact Cary Gastroenterology

The use of cannabis has soared in recent years, and the medical community is still learning about the long-term effects on humans. If you are a regular cannabis user and have been experiencing nausea and episodes of vomiting, you may be suffering from cannabinoid hyperemesis syndrome. At Cary Gastro, we are dedicated to being a trustworthy healthcare provider for all our patients. Please contact us today to request an appointment.