Among nearly 25,000 cannabis-associated ER visits by 15-24 year olds, 21.7% involved syncope (fainting), and the prevalence of syncope was 8.6 times higher among cannabis users than non-users.
Emergency medicine physicians, cannabis users, public health communicators, adolescent health providers
What the researchers found
Analyzing NEISS data from 2019-2022, researchers found that among 24,922 cannabis-associated injuries in young people aged 15-24, 5,400 (21.7%) also involved syncope. The prevalence of syncope among cannabis users was 8.6 times higher than among non-users (PR=8.6, 95% CI: 7.1-10.2). Most injuries were to the head and neck, with falls being the most common mechanism, suggesting syncope leads to fall-related injuries.
Why it matters
Cannabis-related syncope is underrecognized as a cause of injury in young people. The 8.6-fold higher prevalence suggests a strong association that may be clinically significant, particularly as cannabis potency and use increase.
The numbers in context
24,922 cannabis-associated injuries (ages 15-24); 5,400 with syncope (21.7%); syncope prevalence ratio 8.6x vs non-cannabis users (95% CI: 7.1-10.2); most injuries to head/neck; falls most common mechanism
How the study worked
Cross-sectional study using the National Electronic Injury Surveillance System (2019-2022). Identified cannabis-associated injuries among 15-24 year olds presenting to emergency departments and screened for concurrent syncope. Calculated prevalence ratios comparing syncopal rates between cannabis users and non-users.
What this study cannot tell us
NEISS captures injuries leading to ER visits, not all cannabis-related syncope events. Cannot determine causation. Cannabis association based on screening, not confirmed as the cause of syncope. Cannot assess THC dose, product type, or timing relative to use. No information on underlying cardiovascular conditions.
How to read the evidence
Moderate: national surveillance data with large sample, but cross-sectional design and cannot confirm cannabis as the cause of syncope.
When this study was published
2025 publication using 2019-2022 data
The bigger picture
Syncope after cannabis use is likely related to orthostatic hypotension (blood pressure drop on standing), a known cardiovascular effect of THC. As cannabis products become more potent, the incidence and severity of syncope-related injuries may increase.
Questions still open
- Is syncope risk dose-dependent with THC potency?
- Should cannabis users be counseled about orthostatic precautions?
Read the original research
Syncope among adolescents and young adults seeking treatment for cannabis-related injuries.
The American journal of emergency medicine, 92, 109-113
Citation
Hammig, Bart; Bordelon, Abigail. (2025). Syncope among adolescents and young adults seeking treatment for cannabis-related injuries.. The American journal of emergency medicine, 92, 109-113. https://doi.org/10.1016/j.ajem.2025.03.003
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