Cannabis hyperemesis patients had similar hair THC levels as recreational users without vomiting | Research

The takeaway

Hair cannabinoid analysis found similar THC concentrations in people with cannabis hyperemesis syndrome and recreational users without symptoms, suggesting heavy use is necessary but not sufficient to trigger the condition.

Emergency physicians, cannabis users experiencing cyclic vomiting, and researchers studying cannabinoid adverse effects.

220 vs 150 pg/mg (similar)

What the researchers found

Hair cannabinoid concentrations were similar between cannabis hyperemesis patients (THC median 220 pg/mg), recreational user controls (150 pg/mg), and emergency department controls (270 pg/mg). The only significant difference was a 2.6-fold lower THC:CBN ratio in hyperemesis cases compared to recreational user controls.

Why it matters

Cannabis hyperemesis syndrome remains poorly understood. This study suggests it is not simply caused by consuming more cannabis than others. Individual susceptibility likely plays a role, similar to motion sickness or morning sickness.

The numbers in context

Hair THC: cases 220 pg/mg (median), recreational controls 150 pg/mg, ED controls 270 pg/mg. THC:CBN ratio was 2.6-fold lower in cases (95% CI 1.3-5.7). Hair CBD was often unquantifiably low in all groups. 46 total subjects analyzed.

How the study worked

Age- and sex-matched case-control study comparing hair cannabinoid concentrations (THC, CBN, CBD, THC-COOH) in 16 cannabis hyperemesis patients, 16 recreational user controls, and 14 emergency department controls. All subjects had positive urine THC.

What this study cannot tell us

Small sample size (16 cases). Hair analysis reflects average exposure over months but cannot capture acute dosing patterns. The THC:CBN ratio finding needs replication. Specific cannabis products and consumption methods were not controlled.

How to read the evidence

Rated preliminary due to small sample size and the novel nature of using hair analysis for this condition.

When this study was published

Published in 2019. Cannabis hyperemesis syndrome continues to be an active area of emergency medicine research.

The bigger picture

If hyperemesis were purely dose-dependent, heavy users would show higher cannabinoid levels. They did not. This points toward idiosyncratic susceptibility, which could eventually lead to identifying who is at risk before symptoms develop.

Questions still open

What does the lower THC:CBN ratio in hyperemesis patients mean mechanistically? Are there genetic factors that predispose certain heavy users to hyperemesis? Could the THC:CBN ratio serve as a biomarker for risk?

Common questions

What is cannabis hyperemesis syndrome?

A condition characterized by repeated episodes of severe vomiting in regular cannabis users. It is often relieved by hot showers and resolves with cannabis cessation.

Does using more cannabis cause hyperemesis?

Heavy use appears necessary, but this study found that hyperemesis patients did not have higher hair THC levels than heavy users without symptoms. Individual susceptibility likely plays a role.

What was different about the hyperemesis patients?

The only significant difference was a lower THC:CBN ratio in their hair, meaning they had relatively less THC compared to cannabinol. The significance of this finding is unclear.

Read the original research

Hair cannabinoid concentrations in emergency patients with cannabis hyperemesis syndrome.

CJEM, 21(4), 477-481

View on PubMed ↗Publisher’s paper ↗

Citation

Albert, Khala; Sivilotti, Marco L A; Gareri, Joey; Day, Andrew; Ruberto, Aaron J; Hookey, Lawrence C. (2019). Hair cannabinoid concentrations in emergency patients with cannabis hyperemesis syndrome.. CJEM, 21(4), 477-481. https://doi.org/10.1017/cem.2018.479