Medical Cannabis Paradoxical Effects: Cannabinoid Hyperemesis Syndrome and Overreliance on THC
Article Interview with by Codi Peterson
Read time: 3 mins
One of the first widely accepted symptoms that medical cannabis was used as a therapeutic option was chemotherapy-induced nausea and vomiting. Yet, with the globally increasing numbers of medical cannabis patients, a lesser-known but significant paradox is emerging: Cannabinoid Hyperemesis Syndrome (CHS). In this condition, long-term cannabis use can result in severe nausea and vomiting.
In a recent conversation, Codi Peterson, an American paediatric pharmacist specialising in cannabis science, and Adam Isaac Miller, an Australian cannabis industry professional, discuss the complexities of CHS. Exploring how this phenomenon raises important questions about cannabis dosing, patient education, and the broader consequences of industry trends favouring THC potency over cannabinoid diversity.
Understanding CHS: When THC Becomes Problematic
Cannabinoid Hyperemesis Syndrome, first described in 2004, presents as recurrent episodes of intractable nausea and vomiting, regularly accompanied by a desire for hot showers or baths to relieve symptoms. Other symptoms can include abdominal pain, increased thirst and sweating. Unlike typical cases of gastrointestinal pathology, CHS is linked to prolonged cannabis use—particularly high-dose THC-dominant products.
“How can THC be both anti-nausea and pro-nausea?” Peterson asks. “Cannabinoids often exhibit biphasic effects—what works in small doses may cause the opposite in large, chronic doses.” This principle aligns with research suggesting that CB1 receptor overstimulation can dysregulate the body’s endocannabinoid system, leading to paradoxical nausea.
“Not everyone develops CHS, just like not everyone gets caffeine-induced anxiety,” Miller adds. “It likely comes down to genetic susceptibility and usage patterns.” A study by Ethan Russo and colleagues from 2022 identified six genetic markers potentially linked to CHS, indicating that some individuals are more predisposed to developing this condition than others.
The Impact of a THC-Centric Industry
The cannabis industry’s focus on THC potency may be exacerbating the issue. The current cannabis market has evolved to favour high-THC strains, with little regard for other cannabinoids and terpenes that could act as therapeutic equalisers.
“We’ve pigeonholed ourselves into breeding for THC dominance,” Peterson explains. “Consumers chase high THC percentages, but we know that cannabinoids work best in synergy—yet we’ve systematically removed diversity from the plant.”
The impact of increased THC percentage is apparent in retail pricing trends. According to Miller, “People buy based on price and THC percentage. That’s all they’re given to compare, so that’s how they value it. But this race to the highest THC percentage could be harming patients who actually need more balanced cannabinoid profiles.”
The broad-spectrum cannabis formulations with CBD, CBG, and other minor cannabinoids have great potential in their own right and perhaps prospects for mitigating adverse effects associated with THC overuse. Yet, as it stands, industry incentives do not align with promoting balanced products, making patient education a critical component of harm reduction.
Implications for Healthcare Providers
One of the most salient issues is physician awareness - beyond those involved in prescribing or researching medical cannabis. “Emergency departments often misdiagnose CHS,” Peterson notes. “Patients are frequently dismissed or treated with ineffective anti-nausea medications, which don’t work because they’re targeting the wrong mechanism.”
CHS poses a diagnostic challenge, often mistaken for cyclic vomiting syndrome, gastroenteritis, or food poisoning. Many patients undergo extensive, regularly invasive testing before arriving at a CHS diagnosis.
Current best practices suggest haloperidol (Haldol), an older antipsychotic, is the most effective treatment for CHS episodes. “It’s ironic,” Peterson says, “because we’re treating cannabis-induced nausea with a dopamine-blocking antipsychotic, but it works.” Other treatment approaches include benzodiazepines, hydration, electrolyte management, and capsaicin cream, which can mimic the effects of a hot shower by activating TRPV1 receptors.
Some patients find relief from the temporary use of diphenhydramine (the anti-histamine Benadryl), magnesium supplementation or digestive enzymes as acute relief from symptoms at home.
CHS Patient Education and the Importance of Clear Recovery Timelines
One of the major barriers to successfully treating CHS is patient’s disbelief in the cause of their hyperemesis. When diagnosed with CHS, patients often expect immediate relief upon stopping cannabis, but CHS frequently follows a distinct recovery timeline. Peterson outlines that the first-week post-cessation is the most difficult, with sporadic episodes of vomiting persisting for up to 30 days. This delayed resolution of symptoms makes it difficult for patients to recognise the connection and is a key reason why patients can abandon cannabis as the cause and resume cannabis use.
“When patients continue vomiting after quitting, they assume cannabis wasn’t the problem,” Peterson explains. Additionally, most physicians fail to educate patients on how THC metabolites linger in fat stores. For most, symptoms resolve within 4-6 weeks - but patients should be made aware that symptoms can linger.
Beyond nausea and vomiting, other symptoms associated with CHS include prolonged food and smell sensitivities, which may last a year or more post-cessation. Many patients report persistent digestive issues or hypersensitivity to certain odours, further complicating recovery.
Codi recommends a full six months of abstinence and comprehensive patient education to support patients through this transition before potentially reintroducing any cannabinoid treatment.
Moving Beyond the THC Arms Race
Rethinking our approach to THC prescribing and THC-related complications is essential to mitigate the growing prevalence of CHS in both the medical community and the cannabis industry.
Patient Education: Users need to be informed about the risks of chronic, high-dose THC exposure. Miller notes, “We teach people about alcohol moderation. Why don’t we teach cannabis moderation?”
Strain Diversity: Breeding for cannabinoid diversity—incorporating a more balanced approach to cannabis therapy.
Regulatory Adjustments: The addition of labelling requirements beyond just THC percentage, incorporating terpene profiles and minor cannabinoid content.
Physician Awareness & Training: The medical community must recognise CHS early to reduce prolonged suffering and misdiagnosis.
Ever present reminders
The Insiders Extract's latest conversation with Codi Peterson and Adam Miller highlights an often overlooked consequence of medical cannabis use. CHS serves as a stark reminder that the increasing commercialisation of cannabis must be balanced with responsible physician and patient education.
As research on CHS and cannabis pharmacology evolves, academic researchers, healthcare providers and industry leaders must work collaboratively to ensure that cannabis remains a safe and effective option—without falling into the pitfalls of oversimplified marketing and misinformed consumption practices.
Codi Peterson is a pediatric pharmacist and cannabis science educator who serves as the Chief Science Officer of The Cannigma. With a PharmD from Duquesne University and an MS in Medical Cannabis Science & Therapeutics from the University of Maryland, he brings clinical expertise and specialized knowledge to his work in cannabinoid pharmacology. Based in Southern California, Codi maintains an active practice at CHOC Children's Hospital, teaches at UC Irvine School of Pharmacy as an Associate Clinical Professor, and is a founding member of the Pharmacists' Cannabis Coalition of California. Self-described as a "cannabis nerd with a pharmacology problem," he's dedicated to translating complex endocannabinoid science into accessible education for both healthcare professionals and the public.
Disclaimer: This information is shared with a global readership for educational purposes only and does not constitute medical or business advice. All patient-related information has been de-identified OR fictional to protect privacy. Nothing in this article is intended to promote the use or supply of medical cannabis to members of the public.
