Marijuana-Related Hospitalizations, ER Visits, and Poison Control Calls All Increased in Colorado After Legalization
In Colorado, marijuana-related hospitalizations doubled (274 to 593 per 100,000), ER visits with marijuana codes had 5x more mental illness, and poison control calls nearly doubled again after recreational legalization in 2014.
Quick Facts
What This Study Found
Analyzing Colorado health data from 2000-2015, the study documented escalating marijuana-related healthcare contacts across three measures.
Hospitalizations with marijuana-related billing codes increased from 274 per 100,000 in 2000 to 593 per 100,000 in 2015, more than doubling over the period. The increase accelerated after both medical (2010) and recreational (2014) liberalization.
Among ER visits with marijuana-related codes, the prevalence of mental illness was five-fold higher (5.07) than ER visits without marijuana codes, suggesting a strong association between marijuana-related emergencies and psychiatric conditions.
Poison control calls remained stable from 2000-2009, then significantly increased from 42 to 93 after medical marijuana policy liberalization in 2010. After recreational legalization in 2014, calls increased another 79.7% (from 123 to 221). Calls involving children under 17 also increased after 2014.
Key Numbers
Hospitalizations: 274 to 593 per 100,000 (2000-2015). Mental illness prevalence in marijuana ER visits: 5.07x higher than non-marijuana visits. Poison control calls: 42 (2009) to 93 (2010, post-medical), then 123 to 221 (2013-2014, post-recreational, +79.7%). Under-17 calls also increased after 2014.
How They Did This
Retrospective analysis using Colorado Hospital Association data (hospitalizations and ER visits with marijuana billing codes), and Regional Poison Center marijuana exposure calls, from 2000 to 2015.
Why This Research Matters
Colorado is the most-studied natural experiment in cannabis legalization. These data provide concrete evidence that legalization is associated with increased marijuana-related healthcare utilization. The five-fold higher rate of mental illness among marijuana ER visits is particularly important for understanding the psychiatric dimensions of cannabis use.
The Bigger Picture
These increases likely reflect multiple factors: true increases in marijuana use and related problems, increased willingness to disclose marijuana use when legal, better diagnostic coding, and greater availability of high-potency products. Disentangling these factors is critical for accurately assessing legalization's public health impact.
What This Study Doesn't Tell Us
Billing code-based analysis may capture marijuana mentions that are incidental rather than causal. Increased coding and disclosure after legalization may inflate the apparent increase. The study cannot determine what proportion of increased healthcare contacts represents genuinely new problems versus better detection. No comparison state data was included.
Questions This Raises
- ?How much of the increase reflects true new health problems versus better detection and reporting?
- ?Are specific products (edibles, concentrates) driving the increase?
- ?Has the rate of increase stabilized as the legal market has matured?
Trust & Context
- Key Stat:
- Marijuana-related hospitalizations: 274 to 593 per 100,000. Poison control calls: +79.7% after recreational legalization
- Evidence Grade:
- Strong evidence from comprehensive state-level healthcare data spanning 15 years.
- Study Age:
- Published in 2017, using data through 2015. Colorado's market has continued to evolve.
- Original Title:
- Marijuana and acute health care contacts in Colorado.
- Published In:
- Preventive medicine, 104, 24-30 (2017)
- Authors:
- Wang, George Sam(15), Hall, Katelyn, Vigil, Daniel(2), Banerji, Shireen, Monte, Andrew, VanDyke, Mike
- Database ID:
- RTHC-01548
Evidence Hierarchy
Looks back at existing records to find patterns.
What do these levels mean? →Frequently Asked Questions
Did legalization increase marijuana-related health problems in Colorado?
The data shows significant increases in marijuana-related hospitalizations, ER visits, and poison control calls. However, some of the increase likely reflects better detection and reporting after legalization rather than entirely new health problems. The true proportion of each is unknown.
Why do marijuana-related ER visits have so much mental illness?
ER visits with marijuana codes had 5x higher mental illness than those without. This could reflect marijuana triggering acute psychiatric episodes, people with mental illness using marijuana more often, or both. The data cannot determine the direction of causation.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-01548APA
Wang, George Sam; Hall, Katelyn; Vigil, Daniel; Banerji, Shireen; Monte, Andrew; VanDyke, Mike. (2017). Marijuana and acute health care contacts in Colorado.. Preventive medicine, 104, 24-30. https://doi.org/10.1016/j.ypmed.2017.03.022
MLA
Wang, George Sam, et al. "Marijuana and acute health care contacts in Colorado.." Preventive medicine, 2017. https://doi.org/10.1016/j.ypmed.2017.03.022
RethinkTHC
RethinkTHC Research Database. "Marijuana and acute health care contacts in Colorado." RTHC-01548. Retrieved from https://rethinkthc.com/research/wang-2017-marijuana-and-acute-health
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.