Cannabinoid hyperemesis syndrome: A disorder of the HPA axis and sympathetic nervous system?

Cannabinoid hyperemesis syndrome (CHS), a variant of cyclic vomiting syndrome, is an enigmatic and challenging clinical disorder. As cannabis legalization, use, and potency has increased worldwide over the past decade, so has the prevalence of CHS. These patients often require acute care and inpatient treatment for refractory emesis, electrolyte derangement, dehydration, acute renal failure, and injury to the upper gastrointestinal tract. Routinely-prescribed antiemetics are frequently associated with treatment failure in CHS, necessitating use of sedating agents such as benzodiazepines and antipsychotics. Hydrotherapy with hot water provides short-term symptomatic relief from acute episodes of CHS. The reasons for this may be from chronic and/or excessive cannabis use leading to abnormal stimulation of the hypothalamic–pituitary–adrenal axis (HPA) and sympathetic nervous system (SNS) in CHS patients. Overuse of cannabis may also lead to dysfunction of the endocannabinoid system, which is essential for allostasis of the autonomic nervous system after stress.