What Is Cannabinoid Hyperemesis Syndrome?

Long-term use of cannabis can lead to a condition called “cannabinoid hyperemesis syndrome” (CHS), which is characterized by repeated episodes of vomiting. Cannabinoids are compounds (e.g., THC, CBD, etc.) found in the Cannabis sativa plant. They bind to cannabinoid receptors in the brain, spinal cord, GI tract, and other cells in the body. “Hyperemesis” means severe vomiting. CHS can cause serious health issues if left untreated.

It is unclear how common cannabinoid hyperemesis syndrome is. One U.S. study found that among self-reported frequent marijuana users who visited the ER for treatment, approximately 33% showed symptoms of CHS. A Canadian study found that between 2014 and 2021, ER visits associated with CHS-related issues dramatically increased by 13-fold.

Symptoms

The main symptom of cannabinoid hyperemesis syndrome is repeated vomiting or dry-heaving (as many as five times an hour). Other symptoms include the following:

• Intense abdominal pain
• Fear of vomiting
• Loss of appetite
• Persistent nausea (typically in the morning)
• Scromiting (such intense pain that it causes screaming while vomiting)
• Weight loss
• Dehydration

Phases

Cannabinoid hyperemesis syndrome is divided into three phases: prodromal, hyperemetic, and recovery.

1. Prodromal phase
   The prodromal phase is most common in adults who have used cannabis since their teenage years. Symptoms include abdominal pain, morning nausea, and the fear of throwing up without actually vomiting. This phase can last from months to years.
2. Hyperemetic phase
   The hyperemetic phase typically lasts 24 to 48 hours. Symptoms include severe nausea and recurrent vomiting. Individuals in this phase will often restrict their food intake and compulsively shower or bathe to alleviate symptoms.
3. Recovery phase
   The recovery phase involves stopping the use of cannabis. Symptoms lessen and gradually cease over the course of a few months.

Causes

The cause of cannabinoid hyperemesis syndrome is unclear. One theory suggests that repeated overstimulation of endocannabinoid receptors impacts the body’s ability to control nausea and vomiting. It is unknown why some individuals who use cannabis on a long-term basis get CHS and other chronic cannabis users do not. Genetics may be involved.

Risk factors

Long-term use of cannabis (typically 10‐12 years) is the leading risk factor for cannabinoid hyperemesis syndrome. CHS tends to impact individuals who have been using cannabis since adolescence and/or who use cannabis more than once a week.