Cannabis Users Knew Less About Its Negative Effects Than Non-Users in an ER Survey | Research

The takeaway

Emergency department patients who used cannabis scored significantly lower on knowledge of negative short-term and long-term effects compared to non-users, suggesting a concerning knowledge gap among the people most directly affected.

Healthcare providers in emergency settings, public health educators, and cannabis users interested in self-education.

Users scored 1.78/5 on long-term harm knowledge vs 2.38/5 for non-users

What the researchers found

Cannabis users scored 2.51/5 on negative short-term effects knowledge versus 3.28/5 for non-users (p = 0.004), and 1.78/5 on negative long-term effects versus 2.38/5 for non-users (p = 0.002). The most common reasons for use were anxiety (40%), pain (38%), recreation (37%), sleep (28%), and depression (20%).

Why it matters

If cannabis users are less aware of potential harms than non-users, public health messaging may not be reaching its target audience. The finding that 76% of ED patients had used cannabis in their lifetime highlights how mainstream use has become, making accurate health literacy even more important.

The numbers in context

N = 169 (65.5% consent rate from 258 eligible). 75.7% reported lifetime cannabis use. Users vs non-users: short-term knowledge 2.51 vs 3.28/5 (p = 0.004), long-term knowledge 1.78 vs 2.38/5 (p = 0.002). Top reasons: anxiety 40%, pain 38%, recreation 37%, sleep 28%, depression 20%.

How the study worked

Prospective survey of 169 consenting ED patients at Penn State Health (May-August 2024). Participants were asked about cannabis use patterns, reasons for use, and knowledge of positive and negative effects. Thematic analysis identified knowledge themes. Users and non-users were compared on knowledge accuracy scores.

What this study cannot tell us

Single-center study at one Pennsylvania hospital. Convenience sample of ED patients may not represent the general population. Knowledge scores were based on researcher-defined "correct" answers, which may not capture nuance. Small sample size limits subgroup analyses.

How to read the evidence

Prospective survey with statistical testing and reasonable response rate, but limited by single-center design and small sample.

When this study was published

Published in 2025 with data from May-August 2024.

The bigger picture

This study adds to growing evidence that cannabis normalization may outpace health literacy. As legal access expands, the emergency department could serve as an important touchpoint for brief educational interventions about cannabis effects.

Questions still open

Would brief ED-based educational interventions improve cannabis health literacy? Is the knowledge gap driving riskier use patterns, or is it simply a correlate of use?

Common questions

What negative effects did users not know about?

The study found gaps in knowledge about both short-term effects (like cognitive impairment and coordination) and long-term effects (like addiction potential and respiratory impacts). Users were more likely to emphasize positive effects.

Why were so many ER patients cannabis users?

The 75.7% lifetime use rate likely reflects both the general population trend toward higher use and the demographics of emergency department patients, who may have higher rates of substance use overall.

Read the original research

Comparison of Perspectives on Cannabis Use Between Emergency Department Patients Who Are Users and Non-users.

The western journal of emergency medicine, 26(6), 1598-1604

View on PubMed ↗Publisher’s paper ↗

Citation

Marco, Catherine A; Becker, Lena; Egner, Matthew; Erturk, Quincy; Sharma, Ayush; Vail, Taylor; Soderman, Caroline; Morrison, Nathan; Sandelich, Stephen. (2025). Comparison of Perspectives on Cannabis Use Between Emergency Department Patients Who Are Users and Non-users.. The western journal of emergency medicine, 26(6), 1598-1604. https://doi.org/10.5811/westjem.47368