Cyclic Vomiting ER Visits Nearly Doubled After Colorado Marijuana Liberalization | Research

The takeaway

After Colorado liberalized medical marijuana in 2009, emergency department visits for cyclic vomiting nearly doubled, and those patients were 3.6 times more likely to report marijuana use.

Read this if you experience nausea or vomiting with regular cannabis use or are interested in how legalization affects emergency care.

1.92x increase in cyclic vomiting ER visits post-liberalization

What the researchers found

Researchers compared emergency department visits for cyclic vomiting before and after Colorado's 2009 medical marijuana liberalization. The prevalence nearly doubled, rising from 41 per 113,262 visits to 87 per 125,095 visits.

Patients presenting with cyclic vomiting after liberalization were 3.6 times more likely to have documented marijuana use compared to those before liberalization.

The researchers could not determine whether the increase was due to more marijuana use, more honest reporting of use, or both.

Why it matters

This was an early population-level study linking marijuana policy changes to measurable shifts in emergency department presentations, contributing to growing recognition of cannabinoid hyperemesis syndrome as a clinical entity.

The numbers in context

Prevalence ratio: 1.92 (95% CI 1.33-2.79); OR for marijuana use documentation: 3.59 (95% CI 1.44-9.00); 36 patients across 128 visits; 2,574 total visits reviewed

How the study worked

Cross-sectional study reviewing 2,574 emergency department visits at a Colorado hospital. Identified 36 patients with cyclic vomiting across 128 visits using ICD-9 codes and Rome III diagnostic criteria. Compared prevalence and marijuana use documentation before and after 2009 liberalization.

What this study cannot tell us

Single hospital study. Cannot distinguish between actual increases in cannabinoid hyperemesis and increased recognition or reporting. Cross-sectional design cannot prove causation. Small number of cyclic vomiting cases (36 patients).

How to read the evidence

Single-center cross-sectional study with a clear temporal comparison, though small case numbers and inability to confirm causation limit conclusions.

When this study was published

Published in 2015 using pre/post 2009 data. Colorado has since fully legalized recreational marijuana, and cannabinoid hyperemesis syndrome is now more widely recognized.

The bigger picture

As cannabis access expands, clinicians need to recognize cannabinoid hyperemesis syndrome. The Colorado data suggested this was not just a rare case report phenomenon but a measurable trend tied to policy changes.

Questions still open

How much of the increase reflects true cannabinoid hyperemesis versus increased marijuana disclosure? Have similar trends appeared in other states that liberalized cannabis? What is the actual prevalence of cannabinoid hyperemesis among regular users?

Common questions

What is cyclic vomiting syndrome?

It is a condition characterized by recurrent episodes of severe nausea and vomiting, with symptom-free intervals between episodes. When caused by chronic cannabis use, it is called cannabinoid hyperemesis syndrome.

Could the increase just be from better reporting?

Possibly. After liberalization, patients may have been more willing to disclose marijuana use, and clinicians may have been more likely to ask. The study could not separate this from actual increases in the condition.

Read the original research

Cyclic vomiting presentations following marijuana liberalization in Colorado.

Academic emergency medicine : official journal of the Society for Academic Emergency Medicine, 22(6), 694-9

View on PubMed ↗Publisher’s paper ↗

Citation

Kim, Howard S; Anderson, John D; Saghafi, Omeed; Heard, Kennon J; Monte, Andrew A. (2015). Cyclic vomiting presentations following marijuana liberalization in Colorado.. Academic emergency medicine : official journal of the Society for Academic Emergency Medicine, 22(6), 694-9. https://doi.org/10.1111/acem.12655