What is cannabis hyperemesis syndrome, including its clinical features, diagnostic criteria, treatment, and prognosis?

Cannabis Hyperemesis Syndrome: Patient Information

What is Cannabis Hyperemesis Syndrome?

Cannabis Hyperemesis Syndrome (CHS) is a condition that develops in chronic, heavy cannabis users and causes severe, cyclic episodes of nausea, vomiting, and abdominal pain that can only be cured by completely stopping all cannabis use. 1, 2

CHS occurs in people who have used cannabis regularly (typically 4 or more times per week) for at least one year before symptoms begin. 1, 2 The syndrome is characterized by at least 3 vomiting episodes per year that come in cycles, with each acute episode lasting less than one week. 1, 2

Key Clinical Features

Hallmark Symptoms

• Cyclic vomiting episodes that occur at least 3 times annually, with severe nausea and vomiting that comes in waves 1, 2, 3
• Abdominal pain accompanying the vomiting episodes, reported in approximately 85% of cases 1
• Compulsive hot water bathing or showering to relieve symptoms, which is highly characteristic and occurs in 44-71% of CHS patients 1, 2, 4

Cannabis Use Pattern

• Daily or near-daily cannabis use is documented in 68-97% of confirmed CHS cases 1
• Symptoms typically develop after more than one year of regular cannabis consumption (at least 4 times per week) 1, 2
• The syndrome can occur regardless of how cannabis is consumed—whether smoked, vaped, or eaten as edibles—because the total THC dose and duration of use are the critical factors, not the method of consumption 4

Important Distinction: CHS vs. Cannabis Withdrawal

CHS is not the same as cannabis withdrawal syndrome. 1

• CHS occurs DURING active, frequent cannabis use and causes vomiting while you are still using cannabis 1
• Cannabis withdrawal occurs AFTER stopping cannabis, with symptoms beginning 24-72 hours after cessation and lasting 1-2 weeks 1
• Cannabis withdrawal includes irritability, anxiety, insomnia, decreased appetite, and gastrointestinal symptoms, but these resolve within 2 weeks 1

Diagnosis

Diagnostic Criteria (All Three Required)

1. Cannabis exposure: At least 1 year of regular use (more than 4 times per week) before symptoms started 1, 2
2. Clinical pattern: Episodic vomiting occurring at least 3 times per year, with acute onset 1, 2
3. Definitive confirmation: Complete symptom resolution after at least 6 months of continuous cannabis abstinence (or a period equal to three typical vomiting cycles for you specifically) 1, 2, 4

Why Diagnosis Can Be Delayed

• CHS is frequently underdiagnosed or misdiagnosed because many healthcare providers are not familiar with it 4
• This leads to extensive unnecessary testing and an average diagnostic delay of several years 1
• Many patients do not initially connect their cannabis use to their vomiting symptoms, attributing them instead to food, alcohol, or stress 1

Treatment and Management

The Only Cure: Complete Cannabis Cessation

Complete and permanent cessation of all cannabis use is the only definitive cure for CHS. 1, 2, 4 This is non-negotiable for long-term resolution.

• Partial reduction of cannabis use does not lead to symptom improvement 1
• Switching to edible forms or different strains does not help 4
• Full abstinence is mandatory for symptom resolution 1, 2

Timeline for Symptom Resolution

• Minimum abstinence required: At least 6 months of continuous cannabis abstinence, or a period equal to three typical vomiting cycles 1, 2, 5
• Some patients may see improvement within 3 months, but 6 months is the gold standard for complete resolution 1, 5
• Symptoms will return if cannabis use is resumed 5, 3

Acute Episode Management (Emergency Department)

When experiencing an acute vomiting episode, the following treatments may provide temporary relief:

• First-line: Benzodiazepines (such as lorazepam 0.5-2 mg every 4-6 hours) are the most effective medications for rapid control of CHS-related nausea and vomiting 1, 2
• Second-line: Antipsychotic medications such as haloperidol or droperidol can reduce hospital stay length by nearly 50% 1, 2
• Adjunctive therapy: Topical capsaicin 0.1% cream applied to the abdomen activates specific receptors and provides consistent symptom relief 1, 2, 6
• Hot showers or baths provide temporary symptomatic relief during acute episodes 2, 3

Medications to Avoid

• Opioids (narcotic pain medications) should never be used for CHS because they worsen nausea, carry high addiction risk, and do not address the underlying problem 1, 2, 4, 3
• Ondansetron (Zofran) may be tried but often has limited effectiveness compared to its use in other conditions 1, 2

Long-Term Preventive Treatment

While working toward complete cannabis cessation:

• Tricyclic antidepressants (specifically amitriptyline) are the mainstay of long-term preventive therapy 1, 2, 4
• Dosing: Start at 25 mg at bedtime, increase by 25 mg weekly, targeting a maintenance dose of 75-100 mg at bedtime 1, 2
• This medication can help reduce the frequency and severity of vomiting episodes 2, 4

Psychological Support

• Cannabis cessation counseling is essential for all patients with CHS 1, 2
• Referral to addiction medicine specialists or substance use counselors is strongly recommended to support sustained abstinence 1, 2
• Anxiety and depression are common in people with CHS, and addressing these mental health concerns improves outcomes 1, 2

Prognosis and What to Expect

If You Stop Cannabis Completely

• Complete and sustained cannabis abstinence leads to full symptom resolution in the vast majority of patients 1, 2, 3
• You must remain abstinent for at least 6 months to confirm the diagnosis and achieve complete resolution 1, 2

Risk of Relapse

• Relapse rates to cannabis use exceed 40% in reported studies 1
• If you resume cannabis use after stopping, the vomiting episodes will return 5, 3
• Ongoing support from healthcare providers, counselors, and support groups is critical to maintain abstinence 1

Common Pitfalls and Important Warnings

Patient Denial

• Many patients do not believe that cannabis is causing their symptoms, especially because cannabis is often used to treat nausea in other conditions 1
• However, chronic heavy use creates a paradoxical effect where cannabis becomes pro-emetic (causes vomiting) rather than anti-emetic 7
• You must accept the connection between cannabis use and your symptoms to achieve recovery 1

Unnecessary Medical Testing

• Once CHS is suspected based on your cannabis use pattern and symptoms, extensive diagnostic testing should be avoided 1, 4
• Repeated endoscopies, CT scans, and other investigations are not helpful and delay appropriate treatment 1

Hot Water Bathing is Not a Long-Term Solution

• While hot showers provide temporary relief during acute episodes, they are not a treatment 2, 3
• Relying on hot water bathing without stopping cannabis perpetuates the cycle of illness 3, 8

Partial Measures Do Not Work

• Cutting back on cannabis use, switching to "safer" products, or using only edibles will not resolve CHS 1, 4
• Only complete, permanent abstinence from all forms of cannabis leads to cure 1, 2

Additional Health Risks of Chronic Cannabis Use

• Chronic cannabis use is linked to higher rates of depression and can worsen existing psychiatric conditions 1
• Approximately 10% of adults with chronic cannabis use develop cannabis use disorder (addiction) 1
• Cannabis users have more than twice the risk of motor vehicle accidents compared to non-users 1

When to Seek Emergency Care

Seek immediate medical attention if you experience:

• Severe, uncontrollable vomiting that prevents you from keeping down fluids 1
• Signs of severe dehydration (dizziness, decreased urination, extreme weakness) 7
• Severe abdominal pain that could indicate a life-threatening condition such as bowel obstruction, pancreatitis, or heart attack 1, 4

Summary of Key Points

• CHS is caused by chronic, heavy cannabis use and causes cyclic vomiting episodes 1, 2
• The only cure is complete and permanent cessation of all cannabis use for at least 6 months 1, 2
• Acute episodes can be managed with benzodiazepines, antipsychotics, and topical capsaicin, but never with opioids 1, 2
• Long-term prevention involves amitriptyline and comprehensive cannabis cessation support 1, 2
• Relapse to cannabis use will cause symptoms to return 5
• Professional addiction counseling and mental health support significantly improve success rates 1, 2