As recreational cannabis becomes legal in more parts of the United States, doctors are paying closer attention to a painful condition that appears to affect some long-term users of the drug.
Cannabinoid hyperemesis syndrome, known as CHS, causes repeated episodes of severe nausea, vomiting and abdominal pain. The condition has been reported more frequently in emergency departments in recent years, although researchers say it remains poorly understood.
James Swartz, a professor of social work at the University of Chicago, began monitoring possible public health effects after Illinois legalized recreational cannabis in 2020. He and colleagues became interested in CHS after seeing a growing number of medical reports describing the condition among regular cannabis users.
The syndrome was first described by Australian doctors in 2004 after they observed habitual cannabis users experiencing recurring vomiting episodes. CHS can resemble cyclic vomiting syndrome, a disorder that causes repeated bouts of nausea, vomiting and abdominal pain lasting several days before disappearing for weeks or months.
Patients with CHS typically have a history of prolonged cannabis use. Their symptoms can improve after they stop using cannabis. Some patients report temporary relief from very hot showers or baths, although doctors do not fully understand why heat appears to help.
The term “scromiting,” sometimes used online to describe patients screaming while vomiting because of severe pain, has also gained attention. Dr. Thangam Venkatesan, an Ohio State University professor and expert on cyclic vomiting syndrome, has criticized the term as derogatory.
Researchers say the increase in CHS cases may partly reflect greater awareness among emergency physicians. However, the trend has also emerged alongside rising cannabis consumption and a major increase in the potency of available products.
Health Canada data cited by researchers shows that THC concentrations in cannabis have risen sharply from levels historically found in dried plants. Some modern products contain substantially higher amounts of the psychoactive compound, with certain concentrates reaching extremely high concentrations.
Frequent use of high-potency cannabis over a long period appears to be an important risk factor for CHS. Swartz advises users to pay attention to both the strength and frequency of cannabis consumption.
The condition received its own ICD-10 code in 2025, making it easier for doctors to record CHS specifically in medical records.
Researchers are also examining links between heavy cannabis use and mental health disorders. Studies have associated frequent use of high-potency cannabis with a higher risk of schizophrenia and psychosis, although the relationship is complex and may involve underlying genetic and psychological factors.
Mental health conditions also appear to occur alongside CHS in some patients. Experts say it is not yet clear whether people use cannabis to manage existing problems, whether cannabis contributes to those problems, or whether other factors explain the overlap.
Stopping cannabis can be difficult, particularly for people who use it to cope with other concerns. Swartz says treatment needs to address the reasons behind cannabis use rather than simply telling patients to quit.
