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Study breakdown

Cannabinoid Hyperemesis Syndrome: When Cannabis Causes the Nausea It's Known to Treat

Case ReportPreliminary evidence
The takeaway

A case report and literature review highlighted cannabinoid hyperemesis syndrome, where chronic cannabis users experience severe cyclical vomiting that only resolves with cannabis cessation.

Read this if you use cannabis regularly and experience unexplained cyclical nausea or vomiting.

Cannabis cessation resolved symptoms in the majority of CHS patients.

What the researchers found

The authors presented a case of cannabinoid hyperemesis syndrome (CHS) encountered in an outpatient clinic and reviewed the existing literature. CHS is characterized by cyclical episodes of severe nausea and vomiting in chronic cannabis users, often accompanied by compulsive hot bathing, which patients discover temporarily relieves symptoms.

The condition is paradoxical because cannabis is well known for its anti-nausea properties, yet chronic use can trigger this severe vomiting syndrome. Understanding the diagnostic criteria and risk factors can prevent unnecessary and expensive investigations, as patients often undergo extensive workups including imaging and endoscopy before CHS is recognized.

Abstaining from cannabis leads to symptom resolution in the majority of patients.

Why it matters

CHS is frequently misdiagnosed because clinicians may not connect vomiting with cannabis use, given cannabis's well-known anti-nausea properties. Patients often undergo expensive and invasive testing before the diagnosis is considered. Greater awareness can reduce healthcare costs and lead to faster symptom resolution.

The numbers in context

The literature review covered patients over 18 years of age with CHS. Abstaining from cannabis resolved symptoms in the majority of patients.

How the study worked

This was a case report from an outpatient clinic combined with a literature review using PubMed, limited to patients over 18 years of age with cannabinoid hyperemesis syndrome.

What this study cannot tell us

Case reports provide the lowest level of evidence for clinical decision-making. The pathophysiology of CHS remains poorly understood, and the review does not quantify how common the condition is among chronic cannabis users.

How to read the evidence

Preliminary evidence from a case report and literature review. CHS is a recognized clinical entity, though the evidence base consists primarily of case reports and series.

When this study was published

Published in 2016. CHS has become more widely recognized since this publication as cannabis use has increased.

The bigger picture

As cannabis use increases with legalization, CHS cases are becoming more common. The condition challenges the simple narrative that cannabis is universally anti-nausea and highlights how chronic use can produce effects opposite to those seen with acute use.

Questions still open

  • What is the mechanism by which chronic cannabis use switches from anti-emetic to pro-emetic effects? Why does hot bathing provide temporary relief? What proportion of daily cannabis users develop CHS? Are there genetic or consumption pattern risk factors?

Common questions

What is cannabinoid hyperemesis syndrome?
CHS is a condition where chronic cannabis users develop cyclical episodes of severe nausea and vomiting. Patients often discover that hot showers or baths temporarily relieve symptoms. The condition resolves when cannabis use stops.
How is CHS different from normal nausea?
CHS follows a cyclical pattern with distinct phases: a prodromal phase of morning nausea, a hyperemetic phase of intense vomiting, and a recovery phase when cannabis use stops. The compulsive hot bathing behavior is a distinctive feature.

Read the original research

Cannabinoid hyperemesis syndrome.

BMJ case reports, 2016

Citation

Parekh, Jai D; Wozniak, Susan E; Khan, Kamran; Dutta, Sudhir K. (2016). Cannabinoid hyperemesis syndrome.. BMJ case reports, 2016. https://doi.org/10.1136/bcr-2015-213620

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