Cannabis Hyperemesis ER Visits Rose 13-Fold in Ontario, Driven by Commercialization | Research

The takeaway

Emergency department visits for cannabinoid hyperemesis syndrome increased 13-fold over 7.5 years in Ontario, with cannabis commercialization (not legalization itself) associated with the sharpest increase.

Cannabis regulators, emergency medicine providers, public health policymakers

13-fold increase; commercialization drove the jump

What the researchers found

CHS ED visits increased from 0.26 to 3.43 per 100,000 population over 7.5 years (13-fold). Legalization alone was not associated with an immediate change, but commercialization (expanded retail and product variety) was associated with a 49% immediate increase (IRR=1.49). Women showed larger increases than men during commercialization (IRR 1.49 vs 1.08).

Why it matters

This is the first study to distinguish the effects of legalization from commercialization on CHS. The finding that retail expansion and product variety drove the increase has direct regulatory implications.

The numbers in context

12,866 ED visits from 8,140 individuals; 13-fold increase; mean age 27.4; 51.5% female; 8.8% hospitalized; commercialization IRR 1.49; 16.6% had prior mental health visits

How the study worked

Interrupted time-series analysis of linked health administrative databases covering all Ontario residents 15+ from January 2014 to June 2021, examining CHS ED visits across three periods: pre-legalization, legalization, and commercialization.

What this study cannot tell us

Commercialization period coincided with COVID-19, which may have independently affected cannabis use and ED visits. ICD coding for CHS may have improved over the study period.

How to read the evidence

Large population-based interrupted time-series using linked administrative data covering all Ontario residents.

When this study was published

Published in 2022

The bigger picture

The distinction between legalization and commercialization is critical for policy. Simply making cannabis legal did not spike CHS rates, but making it commercially accessible with diverse products did.

Questions still open

Would regulating product potency or limiting retail density reduce CHS rates? Is the gender shift (more women during commercialization) related to product type preferences?

Common questions

Did cannabis legalization increase emergency visits for hyperemesis?

Legalization alone was not associated with an immediate increase. However, commercialization (expanded retail stores and product variety) was associated with a 49% jump in CHS ED visits.

How common is cannabinoid hyperemesis syndrome?

In Ontario, CHS ED visits increased 13-fold from 0.26 to 3.43 per 100,000 population. The condition resulted in 12,866 ED visits from 8,140 individuals over 7.5 years, with 8.8% requiring hospitalization.

Read the original research

Changes in Emergency Department Visits for Cannabis Hyperemesis Syndrome Following Recreational Cannabis Legalization and Subsequent Commercialization in Ontario, Canada.

JAMA network open, 5(9), e2231937

View on PubMed ↗Publisher’s paper ↗

Citation

Myran, Daniel Thomas; Roberts, Rhiannon; Pugliese, Michael; Taljaard, Monica; Tanuseputro, Peter; Pacula, Rosalie Liccardo. (2022). Changes in Emergency Department Visits for Cannabis Hyperemesis Syndrome Following Recreational Cannabis Legalization and Subsequent Commercialization in Ontario, Canada.. JAMA network open, 5(9), e2231937. https://doi.org/10.1001/jamanetworkopen.2022.31937