Cannabis-related emergency room visits increased significantly from 2004 to 2011, especially among teens | Research

The takeaway

Cannabis-related ER visits rose substantially over an eight-year period, with adolescents showing the largest increase in cannabis-only visits and Black Americans disproportionately represented.

Read this if you want to understand trends in cannabis-related emergency visits before widespread legalization.

Adolescent cannabis-only ER visits jumped by 80 per 100,000 from 2004 to 2011

What the researchers found

Between 2004 and 2011, cannabis-only ER visit rates increased from 51 to 73 per 100,000 people aged 12 and older, while cannabis-polydrug visit rates rose from 63 to 100 per 100,000. Both trends were statistically significant.

Adolescents aged 12 to 17 showed the largest increase in cannabis-only ER visits, with a rate difference of 80 per 100,000. Non-Hispanic Black individuals had the most prevalent cannabis-related ER visits across racial and ethnic groups.

Among cannabis-involved visits, older patients were more likely to be hospitalized rather than treated and released, suggesting more severe outcomes with age.

Why it matters

This data captures a period of shifting cannabis attitudes and early legalization efforts in the US. The disproportionate increase among adolescents and racial disparities in ER presentations highlight populations that may need targeted public health attention as cannabis policy continues to evolve.

The numbers in context

Cannabis-only ER visits: 51 to 73 per 100,000 (2004-2011, p=0.004). Cannabis-polydrug visits: 63 to 100 per 100,000 (p<0.001). Adolescents aged 12-17 had the largest rate increase (80 per 100,000 difference).

How the study worked

Researchers analyzed data from the Drug Abuse Warning Network (DAWN), a national surveillance system tracking drug-related ER visits from 2004 to 2011. They examined trends in visit rates stratified by cannabis-only versus polydrug involvement, age, and race/ethnicity. Logistic regression was used to identify factors associated with hospitalization.

What this study cannot tell us

DAWN data relies on ER reporting, which may vary across facilities. Cannabis "involvement" in an ER visit does not necessarily mean cannabis caused the visit. The data ends in 2011, before most state legalizations took effect. Self-reported substance use in ER settings may be unreliable.

How to read the evidence

National surveillance data from DAWN covering eight years. Large sample and systematic data collection, but limited by the observational nature of ER reporting.

When this study was published

Published in 2016, covering data through 2011. DAWN was discontinued, but newer surveillance systems have continued tracking cannabis-related ER trends.

The bigger picture

Rising cannabis-related ER visits during a period of increasing normalization raises questions about whether greater availability and use naturally leads to more acute incidents, or whether other factors like potency increases, edible products, or changing help-seeking behavior contributed. Understanding these patterns is essential for public health planning in legalized markets.

Questions still open

Have cannabis-related ER visits continued to increase after 2011 with widespread legalization? What proportion of these visits involved cannabis as the actual cause versus an incidental finding? Are the racial disparities in ER visits driven by use patterns, access to care, or policing differences?

Common questions

Does this mean cannabis is becoming more dangerous?

Not necessarily. Increased ER visits could reflect more people using cannabis, higher-potency products, new forms like edibles, or simply more willingness to seek medical help. The data cannot distinguish between these explanations.

Why were adolescents the most affected group?

The study found adolescents had the largest rate increase but did not determine why. Possible factors include increasing availability, decreasing perceived risk among teens, and lower tolerance leading to more acute reactions.

Read the original research

Trends and Correlates of Cannabis-involved Emergency Department Visits: 2004 to 2011.

Journal of addiction medicine, 10(6), 429-436

View on PubMed ↗

Citation

Zhu, He; Wu, Li-Tzy. (2016). Trends and Correlates of Cannabis-involved Emergency Department Visits: 2004 to 2011.. Journal of addiction medicine, 10(6), 429-436.