Keynote Presentation: Cannabinoid Hyperemesis Syndrome: Investigating the Mystery with Live Q&A

Cannabinoid hyperemesis syndrome (CHS) is a constellation of intractable vomiting, abdominal pain and hot bathing behavior that solely occurs in the context of heavy chronic use of THC-predominant cannabis or CB1 agonists. It is associated with frequent emergency visits with high associated expense ($30-90K USD). Considerable morbidity and even some fatalities have been reported. The definitive treatment is abstention from cannabis usage, but parenteral haloperidol and cutaneous application of capsaicin ointment can provide symptomatic relief. The etiology of CHS may relate to biphasic dose responses to THC, a paradoxical shift of THC from partial agonist to antagonist of CB1, or effects on the TRPV1 receptor. After ethics approval, a screening questionnaire was posted online. Kits were sent to assess the DNA of patients fulfilling CHS criteria to assess single nucleotide polymorphisms (SNPs) or other mutations as compared to controls without this disorder. 585 people took the survey. Most were high frequency users of cannabis flower or concentrates (93%), using multiple grams/d of THC-predominant material. 15.6% carried diagnoses of cannabis dependency of addiction, and 56.6% experienced withdrawal symptoms. 87.7% of patients with diagnosis or symptoms indicative of CHS were improved after cannabis cessation, most suffering recurrence rapidly after resumption of use. 40 patients returned kits for genomic analysis, 28 CHS patients who carried formal CHS diagnosis and had consistent symptom profiles, and 12 controls with heavy cannabis usage and no CHS symptoms. Findings included mutations in genes coding COMT (p=0.0009), TRPV1 (p=0.021), CYP2C9 (p=0.0414), DRD2 (p=0.027) and ABCA1 (p=0.008), relating to CHS pathophysiology and clinical manifestations. These results shed light on CHS pathophysiology and additional risk factors of this important emerging public health issue.

Learning Objectives: 

1. Define cannabinoid hyperemesis syndrome (CHS) as a condition affecting chronic cannabis users with nausea, vomiting, abdominal pain and hot bathing behavior.

2. Identify CHS pathophysiology.

3. Review the genomic susceptibilities related to a CHS diagnosis.