About one-third of daily marijuana smokers in an ED survey met criteria consistent with cannabinoid hyperemesis syndrome | Research

The takeaway

A survey of 155 daily marijuana smokers (20+ days/month) at an urban ED found that 32.9% met criteria consistent with cannabinoid hyperemesis syndrome, suggesting CHS may affect approximately 2.75 million Americans annually.

Read this if you smoke marijuana daily and experience nausea or vomiting, especially if hot showers provide relief.

32.9% of daily marijuana smokers met CHS criteria; ~2.75 million Americans estimated affected

What the researchers found

Researchers surveyed patients aged 18-49 at the oldest public hospital in the United States, screening for those who smoked marijuana at least 20 days per month.

Of 2,127 patients approached, 155 met the criteria of smoking 20 or more days per month. Among these frequent users, 32.9% (95% CI: 25.5-40.3%) met criteria for a phenomenon consistent with cannabinoid hyperemesis syndrome (CHS).

CHS classification was based on reporting nausea and vomiting combined with rating hot showers as 5 or more on a 10-point relief scale. Hot shower relief is considered a hallmark symptom of CHS that distinguishes it from other causes of cyclic vomiting.

Extrapolating to the general population, the researchers estimated that approximately 2.75 million Americans (95% CI: 2.13-3.38 million) may suffer annually from a phenomenon similar to CHS.

Why it matters

CHS has been considered rare, but this is the first study attempting to estimate its prevalence among heavy users. A 33% rate among daily smokers, if confirmed, would make CHS far more common than previously assumed and an important consideration for cannabis users and clinicians.

The numbers in context

2,127 patients approached, 155 met daily smoking criteria. 32.9% (95% CI: 25.5-40.3%) met CHS criteria. Estimated 2.75 million Americans annually (2.13-3.38 million). Used 20+ days/month as frequent use cutoff.

How the study worked

Cross-sectional questionnaire administered to a convenience sample of ED patients aged 18-49 at an urban public hospital. Screened for marijuana use 20+ days/month. CHS defined by nausea/vomiting plus hot shower relief rating of 5+/10. National prevalence extrapolated from sample.

What this study cannot tell us

Convenience sample from a single urban ED is not representative of all cannabis users. The CHS classification relied on a proxy measure (hot shower relief rating) rather than clinical diagnosis. Self-reported marijuana use frequency may be inaccurate. The national prevalence extrapolation from a single-site ED sample is speculative. The survey could not rule out other causes of nausea and vomiting.

How to read the evidence

Single-site convenience sample with proxy CHS classification provides moderate evidence on prevalence, though the estimate requires validation in larger, representative samples.

When this study was published

Published in 2018. Cannabis potency has increased since, potentially affecting CHS prevalence. Awareness and diagnosis of CHS have also improved.

The bigger picture

Clinicians have long described CHS as rare or very rare without data to support that characterization. This prevalence estimate, while requiring validation, suggests CHS may be substantially underdiagnosed and that emergency department visits for cyclic vomiting in cannabis users should routinely consider CHS.

Questions still open

Would a clinical diagnosis of CHS confirm the 33% prevalence among daily users? What frequency and duration of use triggers CHS? Do specific cannabis products or consumption methods increase CHS risk?

Common questions

How common is cannabinoid hyperemesis syndrome?

This study found 32.9% of people who smoke marijuana 20+ days per month met criteria consistent with CHS. If extrapolated nationally, approximately 2.75 million Americans may be affected. However, this was a single-site study and the estimate needs validation.

How was CHS identified?

Patients who smoked marijuana 20+ days per month and rated hot showers as 5 or more out of 10 for nausea/vomiting relief were classified as having CHS-consistent symptoms. Hot shower relief is considered a hallmark distinguishing feature of CHS.

Read the original research

The Prevalence of Cannabinoid Hyperemesis Syndrome Among Regular Marijuana Smokers in an Urban Public Hospital.

Basic & clinical pharmacology & toxicology, 122(6), 660-662

View on PubMed ↗Publisher’s paper ↗

Citation

Habboushe, Joseph; Rubin, Ada; Liu, Haoming; Hoffman, Robert S. (2018). The Prevalence of Cannabinoid Hyperemesis Syndrome Among Regular Marijuana Smokers in an Urban Public Hospital.. Basic & clinical pharmacology & toxicology, 122(6), 660-662. https://doi.org/10.1111/bcpt.12962