Activation of neurological cannabinoid receptors can aid in preventing nausea and vomiting, particularly so in patients undergoing chemotherapy. Considering the usual effects of THC and other cannabinoids on receptors in the brain, cannabinoid hyperemesis syndrome (CHS) seems to be a paradoxical condition. So why do some individuals suffer from this syndrome?

First described in 2004, CHS typically affects long term consumers of cannabis more so than casual users. It is a condition characterized by chronic cannabis use, cyclic episodes of nausea and vomiting, and excessive bathing or showering with hot water to abate the symptoms and to find relief. As more states legalize cannabis for medical and adult recreational use, emergency departments across the country are seeing a rise in the number of individuals diagnosed with Cannabinoid Hyperemesis Syndrome (CHS).

It has been proposed that receptors in the brain stop responding to cannabis in their usual manner in some individuals. Meanwhile, cannabinoid receptors in the gastrointestinal track that seem to have the opposite effects on nausea and vomiting are still activated. When this happens, gastrointestinal receptors that are no longer overshadowed by the effects of cannabis in the brain lead to abdominal discomfort, pain, and nausea.

CHS is divided into three stages; prodromal, hyperemetic, and recovery phases. In the prodromal phase, individuals may experience early morning nausea and abdominal pain, though most will continue with normal eating patterns. Some may increase their consumption of cannabis, seeking relief from the general discomfort. This phase is often misdiagnosed due to nonspecific symptoms and may last for months to years.

RELATED: How Safe Is It To Smoke Marijuana Every Day?

In the hyperemetic phase, individuals have continued nausea, multiple episodes of vomiting, increased abdominal pain, decreased food intake and weight loss, as well as dehydration. During this period, hot showers tend to alleviate the discomfort and nausea. This phase may continue until an individual completely discontinues use of cannabis. It usually takes one to two days for the hyperemetic phase to resolve.

Treatment is palliative in the hyperemetic phase as it takes time for the endocannabinoid system to return to an inactivated state. IV fluids are given to prevent or treat dehydration, antiemetics and proton pump inhibitors are given to decrease vomiting and nausea, as well as capsaicin cream applied to the stomach.¹ Finally, in the recovery phase an individual will begin to resume normal eating habits and will stop suffering from gastrointestinal issues. This phase may last days or weeks, however symptoms may come back upon use of cannabis.

RELATED: 10 Glorious Cannabinoids In Marijuana And What They Can Do For You

It has been theorized that the recent uptick in cases of CHS may be due to the increased availability of high potency THC products.¹ However, a recent Canadian study indicates that other factors may be at play. Two groups were compared, one suffering from CHS, and one that consisted of cannabis users who were not. The study found there was not an obvious correlation between cannabinoid concentrations in individuals and CHS occurring.4 In any case, further research on the specific cannabinoids and receptors involved will be necessary to fully understand CHS moving forward.