Cannabis Hyperemesis ER Visits Rose 13-Fold in Ontario, Driven by Commercialization
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.
Quick Facts
What This Study 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).
Key Numbers
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 They Did This
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.
Why This Research 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 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.
What This Study Doesn't 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.
Questions This Raises
- ?Would regulating product potency or limiting retail density reduce CHS rates?
- ?Is the gender shift (more women during commercialization) related to product type preferences?
Trust & Context
- Key Stat:
- 13-fold increase; commercialization drove the jump
- Evidence Grade:
- Large population-based interrupted time-series using linked administrative data covering all Ontario residents.
- Study Age:
- Published in 2022
- Original Title:
- Changes in Emergency Department Visits for Cannabis Hyperemesis Syndrome Following Recreational Cannabis Legalization and Subsequent Commercialization in Ontario, Canada.
- Published In:
- JAMA network open, 5(9), e2231937 (2022)
- Authors:
- Myran, Daniel Thomas(2), Roberts, Rhiannon(2), Pugliese, Michael(13), Taljaard, Monica, Tanuseputro, Peter, Pacula, Rosalie Liccardo
- Database ID:
- RTHC-04091
Evidence Hierarchy
Looks back at existing records to find patterns.
What do these levels mean? →Frequently Asked 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.
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Cite This Study
https://rethinkthc.com/research/RTHC-04091APA
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
MLA
Myran, Daniel Thomas, et al. "Changes in Emergency Department Visits for Cannabis Hyperemesis Syndrome Following Recreational Cannabis Legalization and Subsequent Commercialization in Ontario, Canada.." JAMA network open, 2022. https://doi.org/10.1001/jamanetworkopen.2022.31937
RethinkTHC
RethinkTHC Research Database. "Changes in Emergency Department Visits for Cannabis Hypereme..." RTHC-04091. Retrieved from https://rethinkthc.com/research/myran-2022-changes-in-emergency-department
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.