IMPORTANCE: Cannabinoid hyperemesis syndrome (CHS), ie, recurrent emesis from chronic cannabis use, is increasingly observed in emergency departments (EDs), yet population-level estimates and sociodemographic correlates remain underexplored.

OBJECTIVE: To estimate CHS prevalence in US EDs, assess trends from 2016 to 2022, and examine sociodemographic associations.

DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study, using data from the Nationwide Emergency Department Sample (approximately 85% of annual US ED visits) examined patients aged 12 years and older. Patients with ED visits related to pregnancy, gastroparesis, or chemotherapy were excluded.

MAIN OUTCOMES AND MEASURES: ED visits were grouped into 4 categories. Primary outcome was comparative temporal trends between each of the 4 categories: (1) no cannabis use or cyclic vomiting syndrome (CVS); (2) cannabis-related condition only; (3) CVS only; and (4) both cannabis-related condition and CVS (CHS proxy). Restricted cubic splines modeled temporal trends; multinomial logistic regression identified sociodemographic factors associated with CHS.

RESULTS: The analytic sample included 188 610 906 unweighted visits (806 million weighted); 433 251 323 (54.4%) were female; mean (SD) age, 47.9 years (95% CI, 47.8-48.1 years). CHS increased from 4.4 per 100 000 visits, peaked at 33.1 in quarter 2 2020, and remained elevated at 22.3 in 2022; concurrently, CVS-only declined from 300 to 186 per 100 000 visits. Females had lower CHS risk (RRR, 0.92; 95% CI, 0.88-0.95) as did patients in the South vs Northeast (RRR, 0.46; 95% CI, 0.40-0.53); risk was highest at ages 18 to 25 years (RRR, 3.59; 95% CI, 3.38-3.81) and 26 to 35 years (RRR, 2.26; 95% CI, 2.14-2.40).

CONCLUSIONS AND RELEVANCE: In this cross-sectional study of US ED visits, CHS prevalence increased sharply during the COVID-19 pandemic and remained elevated. The findings highlight the need for continued vigilance and refinements to the clinical recognition of CHS.