People who visited the ER for cannabis had nearly four times the risk of developing an anxiety disorder
Among 12 million Ontarians, those with a cannabis-related ER visit had a 3.7-fold increased risk of anxiety disorder diagnosis within three years, with young males at highest risk (5.7x).
Quick Facts
What This Study Found
Within 3 years of a cannabis ER visit, 12.3% were diagnosed with anxiety (ED/hospital) vs 1.2% general population (aHR 3.69). Including outpatient: 23.6% vs 5.6% (aHR 3.88). Young males: aHR 5.67. Young females: aHR 3.22.
Key Numbers
12,099,144 individuals. 34,822 cannabis ER visits. 3-year anxiety: 12.3% vs 1.2%. aHR 3.69. Young males: aHR 5.67.
How They Did This
Population-based cohort using Ontario administrative data (2008-2019). 12,099,144 individuals without prior anxiety. 34,822 had cannabis ER visits. Cause-specific hazard models.
Why This Research Matters
Cannabis-related ER visits may identify individuals at very high risk for developing anxiety disorders, offering a clinical window for screening and intervention.
The Bigger Picture
Cannabis ER visits are increasing with legalization. If these visits represent high-risk moments, they offer opportunities for brief intervention that could prevent chronic anxiety.
What This Study Doesn't Tell Us
Cannot determine causation. ER visits represent the most severe reactions. Cannot measure use patterns or potency.
Questions This Raises
- ?Would anxiety screening after cannabis ER visits reduce disorder development?
- ?Is the association driven by cannabis causing anxiety or shared vulnerabilities?
Trust & Context
- Key Stat:
- increased anxiety disorder risk within 3 years of a cannabis ER visit, rising to 5.7x for young males
- Evidence Grade:
- Massive population cohort (12 million) with appropriate hazard modeling. Cannot determine causation.
- Study Age:
- 2024 publication using 2008-2019 data.
- Original Title:
- Development of an anxiety disorder following an emergency department visit due to cannabis use: a population-based cohort study.
- Published In:
- EClinicalMedicine, 69, 102455 (2024)
- Authors:
- Myran, Daniel T(16), Harrison, Lyndsay D(4), Pugliese, Michael(13), Tanuseputro, Peter, Gaudreault, Adrienne, Fiedorowicz, Jess G, Solmi, Marco
- Database ID:
- RTHC-05580
Evidence Hierarchy
Looks back at existing records to find patterns.
What do these levels mean? →Frequently Asked Questions
Does cannabis cause anxiety disorders?
This study found a strong association but cannot prove causation. People prone to anxiety may have stronger adverse reactions to cannabis. The relationship likely runs in both directions.
Why are young males at highest risk?
Young males had 5.7x relative risk, possibly reflecting higher-potency use, biological vulnerability during brain development, or lower baseline anxiety diagnosis rates.
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Cite This Study
https://rethinkthc.com/research/RTHC-05580APA
Myran, Daniel T; Harrison, Lyndsay D; Pugliese, Michael; Tanuseputro, Peter; Gaudreault, Adrienne; Fiedorowicz, Jess G; Solmi, Marco. (2024). Development of an anxiety disorder following an emergency department visit due to cannabis use: a population-based cohort study.. EClinicalMedicine, 69, 102455. https://doi.org/10.1016/j.eclinm.2024.102455
MLA
Myran, Daniel T, et al. "Development of an anxiety disorder following an emergency department visit due to cannabis use: a population-based cohort study.." EClinicalMedicine, 2024. https://doi.org/10.1016/j.eclinm.2024.102455
RethinkTHC
RethinkTHC Research Database. "Development of an anxiety disorder following an emergency de..." RTHC-05580. Retrieved from https://rethinkthc.com/research/myran-2024-development-of-an-anxiety
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.