Trends in Emergency Department Visits Involving Cannabis Hyperemesis Syndrome Identified Using a New Diagnosis Code — United States, January 2023–May 2026

Summary & key facts

Researchers checked U.S. emergency room records from January 2023 to May 2026 to see how often doctors recorded cannabis hyperemesis syndrome, a condition of repeated nausea and vomiting linked to frequent cannabis use. After a new, specific diagnosis code started on October 1, 2025, recorded CHS visits jumped from about 3.4 per 10,000 emergency visits to about 11.3 per 10,000, and monthly counts were roughly 3.7 times higher than before. The increase was largest for people aged 15 to 24 and for females, but the report says the rise may be partly because hospitals started recognizing and coding CHS better, not necessarily because many more people got sick.

Key facts:

• About 200,000 emergency department visits from January 2023 to May 2026 involved cannabis hyperemesis syndrome.
• Before the new diagnosis code, CHS appeared in about 3.4 out of every 10,000 emergency visits in September 2025.
• In October 2025, right after the new code began, CHS recordings rose to about 11.3 out of every 10,000 emergency visits.
• Across the eight months after the new code started, monthly CHS records were roughly 3.7 times higher than the monthly average from January 2023 to September 2025.
• Higher proportions of CHS-related emergency visits were seen in people aged 15 to 24 and in females, with the increase becoming more noticeable in some groups after the code change.
• The report cautions that the sudden and lasting rise in recorded cases might partly reflect better recognition and coding by clinicians, not only an actual increase in how many people develop CHS.

Abstract

Cannabis hyperemesis syndrome (CHS) is a condition characterized by cyclical nausea and vomiting and is associated with frequent cannabis use. Data from CDC's National Syndromic Surveillance Program were analyzed to examine trends in CHS-involved emergency department (ED) visits before and after implementation of a new, CHS-specific International Classification of Diseases, Tenth Revision, Clinical Modification diagnosis code on October 1, 2025. Monthly CHS-involved ED visits per 10,000 all-cause visits were assessed overall and by demographic characteristics. During January 2023-May 2026, a total of 199,565 ED visits involved CHS. During January 2023-September 2025, the proportion of ED visits that involved CHS remained mostly steady. In the first month after implementation of the new diagnostic code, the proportion of CHS-involved ED visits increased from 3.35 per 10,000 ED visits in September 2025 (preimplementation) to 11.26 per 10,000 ED visits in October 2025 (postimplementation). During the first 8 months after implementation of the new code (October 2025-May 2026), average monthly proportions of CHS-involved ED visits were 3.7 times as high as the monthly average during January 2023-September 2025. Higher proportions of CHS-involved ED visits were observed among persons aged 15-24 years and females, with more pronounced impacts among some demographic groups after code implementation. The abrupt, sustained increase might partly reflect improved recognition and coding of CHS rather than a true rise in incidence. These findings highlight a likely underestimated impact of CHS, suggesting the need to strengthen education about the risks associated with frequent cannabis use, expand ongoing surveillance efforts, and improve clinical recognition of CHS through continuing medical education and implementation of routine cannabis use assessment in ED settings.

Topics

Bipolar Disorder and Treatment Cannabis and Cannabinoid Research Psychedelics and Drug Studies

Categories

Health Sciences Medicine Pharmacology

Tags

Code (set theory) Diagnosis code Emergency department Emergency medicine Medical diagnosis Medical emergency Medical record Medicine MEDLINE Pediatrics

Substances

Cannabis

Conditions & symptoms

Substance abuse disorder