Increase in Cannabis-Related Vomiting Syndrome Cases Reported in the US

A seldom-seen vomiting disorder linked to long-term cannabis use is becoming more frequently reported in American emergency departments. Known as cannabinoid hyperemesis syndrome (CHS), the condition involves intense and repeated episodes of nausea, stomach pain, and vomiting.

CHS was first identified in the United States in 2009. Initially, it lacked a national diagnostic code, which made monitoring cases difficult. Emergency room visits remain one of the primary ways to track its occurrence.

Research from the University of Illinois Chicago shows that between 2016 and 2022, CHS-related ER visits rose from about 4 per 100,000 patients to 22 per 100,000. Although still considered rare, the conditions increasing frequency warrants attention, particularly since its symptoms can be prevented by stopping cannabis use.

Not all cannabis users will develop CHS. The syndrome tends to affect only a small fraction of users, often younger individuals, and is associated with frequent or prolonged use. Symptoms usually begin gradually in the early years of cannabis consumption, with mild morning nausea or abdominal discomfort, and can persist for years. Severe episodes typically occur later, producing relentless vomiting and nausea lasting one or two days.

Interestingly, hot showers or baths can temporarily ease these symptoms, while ceasing cannabis use can fully resolve the condition. During the COVID-19 pandemic, studies found a notable rise in CHS prevalence in US emergency departments, likely influenced by increased stress, isolation, and cannabis consumption.

The research analyzed over 800 million ER visits nationwide from 2016 to 2022. Most CHS patients were around 30 years old, with a slight female majority. Cases were more frequent in the Western and Northeastern US than in the South. The rise in reported cases could be due either to increased cannabis use or improved awareness and diagnosis of the syndrome.

CHS is often misdiagnosed as cyclical vomiting syndrome, which requires different treatment. Correct diagnosis involves ruling out other potential causes and confirming cannabis use, though some patients may not disclose this information.

Experts note that the absence of a noticeable increase in CHS before 2020, despite wider cannabis legalization and access to high-potency products, may reflect underdiagnosis or misclassification. The surge in cases post-2020 may be due to both greater exposure and improved diagnostic awareness.

Further research and better diagnostic methods are necessary to determine the true prevalence of CHS. The study was published in JAMA Network Open.

Author: Aiden Foster