What is cannabinoid hyperemesis syndrome?

First described in 2004 by a group of Australian researchers, cannabinoid hyperemesis syndrome (CHS) is a rare medical condition that affects a very small percentage of cannabis users. It comprises three phases:

• Pre-emetic phase: This phase, which can last for months and even years, is characterised by mild symptoms.
• Hyperemetic phase: Characterised by vomiting and abdominal pain, this is the phase when patients become aware of the disease and develop the habit of taking hot showers several times per day, ad this provides significant relief from the symptoms. Paradoxically, some patients try to combat the nausea with marijuana driven by the belief that its antiemetic properties may help reduce the vomiting, when actually the effect is quite the opposite.
• Recovery phase: In this phase patients halt the use of cannabis and symptoms fade until they eventually disappear.

The hyperemetic phase is characterised by:

• Cyclic vomiting
• Back pain
• Symptom relief through hot showers

For some reason yet to be determined, patients report a reduction in nausea and vomiting after taking a hot bath or shower, and even if the reason for this phenomenon is unclear, it provides an excellent means of diagnosis.

In fact, patients suffering from CHS were misdiagnosed with cyclic vomiting syndrome until the disorder was first discovered a decade ago, which was hampered by the fact that cannabis is commonly used as an anti-nausea and anti-vomiting remedy.

Is there a treatment for CHS?

The only effective treatment known to date is the cessation of cannabis use, after which symptoms fade until disappearing completely.

Has legalisation brought an increase in CHS sufferers?

The debate is only just beginning, and while media outlets including the Huffington Post and the Daily Mail have published alarming headlines warning of a rise in hospital admissions for patients reporting the above-described symptoms - a situation they attribute to cannabis having been legalised in states such as Colorado - many have criticised what they considered to be biased information resulting from the stigma that has been attached to the cannabis plant for decades.

In fact, many people attribute the increase in CHS cases to patients being less reluctant to admit cannabis use under the new legal framework. At least this is the conclusion reached by a 2012 study aimed at determining whether the rise in CHS sufferers in Colorado could be related to cannabis liberalisation. According to Mark Malone, the Executive Director of the Cannabis Business Alliance, the new legal environment can by no means account for the increase in patients, as the origin of the disease is unclear yet. "It could simply be an allergy to certain terpenes, to a specific strain or to certain pesticides or fertilizers. The more regulated the cannabis market, the easier it is to control the product," he says.

Is the endocannabinoid system linked in some way to CHS?

Even if the cause of the syndrome has not yet been determined, according to some physicians cannabis abuse could lead to damage and alterations in the endocannabinoid receptors, as no links have been yet established between CHS and CHS sufferers other than prolonged cannabis use. This theory, however, is not supported by evidence and is based on mere conjecture. "The science behind it is not clear. We're just starting to recognize it even exists," says Dr Kennon Heard, an emergency physician at the University of Colorado Hospital in Aurora. "The most likely cause is people using marijuana frequently and in high doses have changes in the receptors in their body, and those receptors become dysregulated is some way, and it starts causing pain."

A malfunctioning of the endocannabinoid receptors?

Could cannabis abuse lead to an overstimulation of cannabinoid receptors that could over time disrupt homeostasis - the stable condition of an organism - causing malfunctioning and pain? Now, while this is certainly a possibility, we can't ignore the fact that cannabis has been commonly used for centuries in different regions throughout the world without CHS cases having been reported until the last decade.

The cannabis community has its say

Even if for now the scientific and medical community attribute CHS to prolonged cannabis use, such a theory does not hold water in the eyes of many, who recall that while cannabis has been used for centuries, it was not until very recently that the disease first emerged, suggesting its origin is not in the plant itself but in pesticides and fertilizers.

 Unlike the black market, the new legal framework has brought about greater control over the product, prompting many growers to replace chemical pesticides with neem oil in order to comply with the new regulations on pest and disease control. However, some argue that despite it being presented as an 'organic' pesticide, the term is no guarantee that neem oil poses no risk to health - many venoms are organic after all.

Neem oil contains a molecule called azadirachtin that is held responsible for CHS by some people, who suggest that this compound could be poisoning neem-grown cannabis oil users.

What is azadirachtin and how does it affect the body?

Found in other organic pesticides as well as in neem oil, the toxicity of this substance has been proven by various scientific studies, which suggest that symptoms of azadirachtin intoxication are similar to CHS symptoms:

• Cyclic vomiting
• Nausea
• Back pain
• Weakness in the limbs
• Depression

Since all the studies that have analysed the symptoms for azadirachtin intoxication so far have focused on oral administration, it is not unreasonable to think that the substance may affect the body differently when inhaled trough the smoke of cannabis. And while the US Organic Materials Review Institute (OMRI) has listed azadirachtin as compliant with organic standards, the real problem with neem oil is not whether it meets the requirements for organic status, but the possible dangers associated with its use in cannabis growing, particularly when applied a few days prior to harvest.

Thus, we at Dinafem recommend limiting the use of neem oil to the growing period, otherwise the pesticide would impregnate the flowers ultimately ending up in the user's body. A theory that opens up the debate on whether the legal cannabis market is implementing sufficient control measures.

The importance of safe crops in the legal market

The cannabis we use needs to be safe, particularly for medical but also for recreational use. And while public opinion is torn between the pros and cons of cannabis legalisation, the markets that have already been regulated, including Canada, Uruguay and some US states, cannot afford to offer a product that has not been subject to the strictest quality controls, as this is precisely one of the major advantages of regularisation. The public deserves organic, pest and disease-free cannabis that raises no safety questions.

In any event, this new syndrome has drawn attention to the need for allocating more resources to research into cannabis and its applications in order to provide consumers in the legal market with a safer product. The regulatory wave is here to stay, so let's do it right.