Cannabis hyperemesis syndrome (CHS) is a rare but serious condition affecting some long-term cannabis users, characterised by severe cyclic vomiting and abdominal pain. As cannabis use continues to rise globally and more countries move towards legalisation, understanding CHS has become increasingly important for both recreational users and medical cannabis patients.
What is Cannabis Hyperemesis Syndrome?
CHS is a complex condition that typically develops in daily cannabis users after several years of regular use. The condition causes repeated episodes of severe nausea, vomiting (sometimes referred to as “scromiting” – a combination of screaming and vomiting that captures the intensity of these episodes) and abdominal pain that can last for days. Peculiarly, many sufferers find that hot showers or baths temporarily relieve their symptoms – a characteristic feature that often helps diagnose the condition.
The syndrome, first documented in 2004, usually develops after 10-12 years of regular cannabis use, though timeframes can vary. CHS predominantly affects young adults aged 18-39 years and is more common in males. A 2019 review of 271 cases found that 69 per cent of people with CHS were male. Despite affecting a relatively small percentage of cannabis users overall, its impact can be severe enough to require hospitalisation.
The three phases of CHS
CHS symptoms present in three stages: the prodromal phase, the hyperemetic phase, and the recovery phase.
1. Prodromal Phase
- Early morning nausea
- Mild abdominal discomfort
- Anxiety about vomiting
- Normal eating patterns usually maintained
- May last months or years
- Often leads to increased cannabis use as people try to relieve symptoms
2. Hyperemetic Phase
- Intense, overwhelming vomiting episodes
- Severe abdominal pain
- Reduced food intake and weight loss
- Dehydration risks
- Compulsive hot showering for temporary relief
- Usually triggers medical intervention
3. Recovery Phase
- Symptoms resolve after cannabis cessation
- Return to normal eating patterns
- Can last days or months
- Symptoms typically return if cannabis use resumes
Why does CHS occur?
While cannabis is well-known for its anti-nausea properties, particularly in medical applications like chemotherapy-induced sickness, long-term use can paradoxically trigger CHS in some individuals. The exact mechanism isn’t fully understood, nor is it known why some people get CHS and others don’t. Research suggests it involves the complex interaction of cannabinoids with CB1 and CB2 receptors throughout the body. One theory suggests that CHS is a result of the overstimulation of these cannabinoid receptors in the endocannabinoid system (ECS).
CB1 receptors are primarily found in the brain and central nervous system, but also exist in the digestive tract, while CB2 receptors are mainly located in immune tissues. Long-term use may alter how these receptors function, particularly in the digestive tract, leading to the characteristic symptoms of CHS.
Diagnosis and treatment
Diagnosing CHS can be challenging, and many patients experience symptoms for years before receiving a correct diagnosis. Key diagnostic criteria include:
- Long-term, regular cannabis use
- Severe cyclic nausea and vomiting
- Abdominal pain
- Temporary relief from hot showers
- Symptoms that resolve with cannabis cessation
Treatment typically involves:
- Immediate cessation of cannabis use
- IV fluids for dehydration
- Anti-nausea medications (though traditional options like ondansetron are often ineffective in CHS cases, and stronger medications like haloperidol may be required)
- Pain management
- In some cases, hospital admission is required for severe cases
- Some patients report relief from capsaicin cream applied to the abdomen
How long does it take to recover from CHS?
Recovery from CHS varies significantly between individuals, but understanding typical timelines can help set realistic expectations for the healing process.
Most people notice their symptoms beginning to subside within 10 days of completely stopping cannabis use. However, severe symptoms may persist during this initial period, and medical supervision is often recommended.
Full resolution of CHS symptoms typically takes several weeks to months. The exact timeframe depends on factors including:
- Duration and frequency of previous cannabis use
- Individual metabolism and physiology
- Overall health status
- Whether any complications developed during acute episodes
Prevention and long-term outlook
The only proven way to prevent CHS is to stop using cannabis entirely. While this might be challenging for some users, especially those using cannabis medicinally, continued use typically leads to recurring episodes.
For medical cannabis patients concerned about CHS, it’s important to:
- Discuss symptoms with your prescribing clinician
- Monitor any early warning signs
- Consider treatment alternatives if symptoms develop
- Seek immediate medical attention for severe vomiting episodes
The bottom line
While CHS affects only a small proportion of cannabis users, its prevalence rises dramatically among heavy users, and its impact can be severe. Cannabis is a powerful plant that is improving – even saving – the lives of thousands of people around the world. Whilst it does have immeasurable therapeutic potential, it’s clear that cannabis isn’t for everyone. As use becomes more widespread and accepted, understanding conditions like CHS becomes increasingly important for both medical patients and recreational consumers. All cannabis users should be aware of CHS warning signs and seek medical attention if symptoms develop.
