Does CHS Alter Bowel Movements?
Cannabinoid Hyperemesis Syndrome (CHS) does not cause diarrhea or altered bowel movements—the syndrome is defined exclusively by cyclic vomiting, nausea, and abdominal pain. 1, 2
Core Clinical Features of CHS
The American Gastroenterological Association explicitly defines CHS by three cardinal symptoms only: stereotypical episodic vomiting, nausea, and abdominal pain, with no mention of diarrhea as a presenting or associated symptom. 2
- CHS is characterized by cyclic episodes of nausea, vomiting, and abdominal pain—but not diarrhea. 2
- The pathophysiology involves CB1 receptor dysregulation in the dorsal vagal complex (which controls emesis), not intestinal motility patterns that would produce diarrhea. 2
- Peripheral CB1 receptor activation affects gastric motility and emptying, not colonic transit acceleration, which explains the absence of diarrhea in CHS. 2
Critical Diagnostic Distinction: CHS vs Cannabis Withdrawal Syndrome
If diarrhea is present alongside vomiting in a cannabis user, consider Cannabis Withdrawal Syndrome (CWS) instead of CHS. 2 This is a crucial clinical pitfall to avoid:
- CHS occurs during active chronic cannabis use with vomiting as the primary symptom. 3
- CWS occurs after cessation of cannabis use (within 24-72 hours) and includes gastrointestinal symptoms such as diarrhea. 3, 2
- Approximately 47% of regular cannabis users experience CWS after stopping heavy and prolonged use, with symptoms including anxiety, irritability, decreased appetite, and gastrointestinal distress including diarrhea. 3, 2
Management of Diarrhea in Cannabis Users
When diarrhea is present in a cannabis user:
- First, rule out life-threatening conditions (acute abdomen, bowel obstruction, mesenteric ischemia, pancreatitis). 2
- Distinguish CHS from CWS based on timing relative to cannabis use: active use suggests CHS (though diarrhea would be atypical), while recent cessation suggests CWS. 2
- For diarrhea in CWS, the American College of Gastroenterology recommends standard antidiarrheal agents such as loperamide. 3, 2
- Avoid opioids entirely as they worsen nausea, carry addiction risk, and do not address underlying pathophysiology. 3
Pathophysiological Explanation
The endocannabinoid system's role in CHS centers on emesis control, not bowel motility:
- CB1 receptors are densely distributed in the dorsal vagal complex, critically important for controlling emesis. 1
- Chronic cannabis use leads to loss of negative feedback on the hypothalamic-pituitary-adrenal axis, resulting in increased vagal nerve discharges contributing to vomiting. 1
- While peripheral CB1 receptors affect gastric motility and gastric acid secretion, the clinical manifestation in CHS is upper GI (vomiting), not lower GI (diarrhea). 1