As more states legalize cannabis, more people are learning whether cannabis is right for them.

Some may be finding that there can be very real — and serious — complications that come with cannabis use.

Many people use cannabis products to treat nausea. Ironically, one of the potential complications of long-term cannabis use is a condition called cannabis hyperemesis syndrome (CHS). It causes severe nausea and vomiting.

CHS is still poorly understood. Researchers are trying to understand why some people develop it and others don’t. Right now, the only known effective treatment for CHS is to stop using cannabis.

It may sound like a made-up condition to discourage teenagers from trying cannabis, but CHS is very real — and it can be dangerous if not properly managed.

In this article, we’ll cover what CHS is, and explain how to identify it.

CHS is caused by cannabis use. It’s characterized by:

  • recurrent vomiting
  • nausea
  • abdominal pain

Compulsive bathing or showering in hot water to soothe nausea is also a hallmark sign of CHS.

CHS is a newly discovered condition. It wasn’t described in scientific literature until 2004.

But a 2019 study concluded that it potentially accounts for up to 6 percent of emergency room visits for recurrent vomiting.

Research suggests that CHS is a permanent condition that can only be effectively treated by quitting cannabis. Continuing to use cannabis despite CHS can lead to potentially life threatening complications.

Regular, long-term cannabis use is the only known cause of CHS.

A 2017 review of studies found that 97.4 percent of people who developed CHS reported using cannabis at least weekly. About 75 percent reported using cannabis regularly for over a year.

It’s thought that genetics may play a role because only a small number of people who regularly use cannabis develop CHS.

One theory behind CHS is that chronic overstimulation of the body’s endocannabinoid receptors leads to your body not being able to control nausea and vomiting.

CHS is divided into three phases depending on the symptoms.

Prodromal phase

The prodromal phase can last for months, or even years in some cases. Symptoms are most common in early middle-aged adults who have used cannabis regularly since adolescence.

Symptoms can include:

Vomiting is absent in this stage.

Hyperemetic phase

The hyperemetic phase is characterized by reoccurring and often overwhelming nausea and vomiting. Other symptoms can include:

Recovery phase

After stopping cannabis use, symptoms generally resolve within days or months. Reusing cannabis again often leads to a reoccurrence of CHS.

It’s still widely unknown how common CHS is or why it only develops in some people.

Many researchers feel that CHS is underrecognized and underdiagnosed. Symptoms of CHS can resemble those of other conditions, such as cyclic vomiting syndrome.

Cannabis is still illegal in many states and countries, so people in these areas may be hesitant to tell their doctor about their cannabis use.

Estimated impact

In one 2018 study, a group of researchers surveyed 2,127 U.S. adults between the ages of 18 and 49 at an emergency department in New York. Of those surveyed, 155 met the criteria of smoking cannabis at least 20 days per month.

The researchers found that 32.9 percent of the participants reported having experienced symptoms of CHS in the past.

Using these results, researchers estimated that approximately 2.75 million U.S. adults may deal with CHS each year. However, much more research needs to be done to fully understand how often CHS occurs.

Researchers are continuing to examine potential treatment options for CHS. As of now, there are no standard treatment guidelines.

Stopping cannabis use is the only known way to permanently get rid of CHS. Symptoms may persist 10 days or more after quitting.

Relief from symptoms

Many people experience temporary relief from their nausea and vomiting when bathing in hot water. Some people with CHS may compulsively bathe in hot water for hours a day to find relief.

Your doctor may recommend a number of other treatments to alleviate your symptoms along with quitting cannabis, such as:

  • Capsaicin cream. A few small case studies found that topical capsaicin may help manage symptoms.
  • Antipsychotics. Antipsychotic medications, such as haloperidol or olanzapine, have provided people relief in some studies.
  • Antihistamines. Benadryl and other antihistamines may be somewhat effective, but research is mixed.
  • Intravenous (IV) solutions. If you become severely dehydrated or can’t handle oral fluid, you may need IV hydration.
  • Pain-relieving medications. If your symptoms are accompanied by abdominal pain, your doctor may prescribe or recommend pain-relieving medication.

Keep in mind none of these treatments will be effective if you continue using cannabis products.

More research needs to be done to understand the long-term effects of CHS. However, chronic vomiting caused by CHS can lead to a number of potentially serious complications, such as:

CHS-related deaths

A 2016 case study describes two deaths due to complications of CHS. The cause of death in both people was found to be hyponatremic dehydration, also known as low sodium levels.

Help quitting cannabis

If you need help quitting cannabis, the Substance Abuse and Mental Health Services Administration offers a 24/7 helpline in English and Spanish.

A representative can refer you to local treatment facilities, support groups, and community-based organizations.

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Even cannabis products that don’t contain THC have the potential to cause or worsen CHS.

It’s still not clear which of the more than 100 cannabinoids found in cannabis are responsible for CHS, but it’s thought that CBD could potentially be a contributor.

Until there’s more research, CBD shouldn’t be considered safe for people with CHS.

CHS is a condition caused by chronic and repeated cannabis use that leads to severe nausea and vomiting.

There’s still a lot about this condition that researchers don’t know, including how common it is and why it occurs in some people but not others.

At this time, the only known way to cure CHS is by quitting cannabis.