Cannabinoid Hyperemesis Syndrome ER Visits Surged During COVID and Stayed High | Research

The takeaway

Emergency department visits for cannabinoid hyperemesis syndrome increased from 4.4 to 33.1 per 100,000 visits during 2016-2022, peaking during COVID-19, with young adults ages 18-25 at 3.6 times higher risk.

emergency physicians, gastroenterologists, heavy cannabis users, public health officials

What the researchers found

CHS-proxy visits increased from 4.4 per 100,000 ED visits in 2016 to a peak of 33.1 in Q2 2020, remaining elevated at 22.3 in 2022. Concurrently, CVS-only visits declined from 300 to 186 per 100,000. Highest risk: ages 18-25 (RRR 3.59) and 26-35 (RRR 2.26). Females had slightly lower risk (RRR 0.92). Southern US had lower risk vs. Northeast (RRR 0.46).

Why it matters

CHS is increasingly recognized but still frequently misdiagnosed as cyclic vomiting syndrome. The sharp rise during COVID may reflect increased cannabis consumption during lockdowns, and the sustained elevation suggests this is not a temporary phenomenon.

The numbers in context

806 million weighted ED visits. CHS rate: 4.4 to 33.1 per 100,000 (peaked Q2 2020), 22.3 in 2022. CVS declined: 300 to 186 per 100,000. Risk: 18-25 years RRR 3.59; 26-35 years RRR 2.26. Female RRR 0.92. South vs. Northeast RRR 0.46.

How the study worked

Cross-sectional analysis of the Nationwide Emergency Department Sample (~85% of annual US ED visits), 2010-2022. 188.6 million unweighted visits (806 million weighted). CHS proxied by co-occurrence of cannabis-related condition and cyclic vomiting syndrome. Restricted cubic splines and multinomial logistic regression.

What this study cannot tell us

CHS identified by proxy (cannabis diagnosis + CVS diagnosis), which may over- or underestimate true prevalence. ICD coding changes during study period. Cannot determine if COVID-era increase was from more cannabis use or more ED visits for vomiting.

How to read the evidence

Very large national dataset covering ~85% of US ED visits, but CHS identified by diagnostic code proxy rather than clinical confirmation.

When this study was published

2025 publication with 2016-2022 data.

The bigger picture

The decline in CVS diagnoses as CHS rises suggests improved recognition of CHS — many previously diagnosed CVS cases may actually have been CHS. The COVID surge and sustained elevation indicate that CHS will become an increasingly common ED presentation.

Questions still open

How many current CVS diagnoses are actually unrecognized CHS?
Will CHS rates continue to rise with increasing cannabis potency?

Common questions

What is cannabinoid hyperemesis syndrome?

CHS is recurrent severe vomiting caused by chronic cannabis use. This study found CHS-related ER visits surged 7.5-fold between 2016 and 2020, with young adults 18-25 at highest risk. Hot showers often provide temporary relief.

Is cannabinoid hyperemesis syndrome becoming more common?

Yes. This study of 806 million US ER visits found CHS visits increased from 4.4 to 33.1 per 100,000 between 2016 and 2020, and remained elevated at 22.3 in 2022. The rise may reflect both increased cannabis use and better clinical recognition.

Read the original research

Cannabinoid Hyperemesis Syndrome, 2016 to 2022.

JAMA network open, 8(11), e2545310

View on PubMed ↗Publisher’s paper ↗

Citation

Swartz, James A; Franceschini, Dana. (2025). Cannabinoid Hyperemesis Syndrome, 2016 to 2022.. JAMA network open, 8(11), e2545310. https://doi.org/10.1001/jamanetworkopen.2025.45310