man smelling cannabis plant
Is cannabis-induced vomiting fact or fiction?

If you consume cannabis on the regular, there’s something you need to know.

The herb is often used as a powerful anti-nausea aid. However, can the plant actually make nausea and vomiting worse in some cases?

A new condition is on the rise and experts think that excessive cannabis consumption may be the trigger.

Over the past fifteen years, medical professionals have documented a growing number of cases of intense vomiting seemingly triggered by prolonged cannabis use.

Coined as “cannabinoid hyperemesis syndrome” an estimated 32.9 percent of chronic cannabis consumers may develop symptoms, according to projected data published in a 2018 study published in the journal Basic and Clinical Pharmacology and Toxicology.

The study included 155 individuals who consumed cannabis more than 20 days out of the month. Of those included, roughly one third experienced intense nausea and vomiting associated with the emerging condition.

By most standards, the cannabis plant is considered reasonably safe to consume.

With few lasting side effects and no known fatalities, the herb is considered one of the most inoffensive substances available.

The cannabis plant also has a long history as a natural anti-nausea and vomiting aid, used by humans for thousands of years with no report of cyclic vomiting in the past.

However, for whatever reason, these newly identified side effects of cannabis consumption are making waves in emergency departments and in the headlines.

What is cannabinoid hyperemesis syndrome?

headache
Do you know anybody who has experienced cannabinoid hyperemesis syndrome?

Simply stated, cannabinoid hyperemesis syndrome (CHS) is a newly defined medical condition that causes bouts of severe vomiting after regular cannabis consumption.

The symptoms of CHS can be very disruptive to everyday life. Nausea, cyclic vomiting, and severe stomach pains are the most common presentations.

However, symptoms may begin slowly over time, causing patients to experience bouts of nausea and stomach pains that do not automatically lead to vomiting.

In most cases, this pain, nausea, and vomiting can be relieved by taking a hot shower. So, many patients expected to have CHS become compulsive bathers.

According to a growing collection of case studies, CHS can affect both men and women. However, the condition appears to affect men more often than their female counterparts.

CHS most commonly presents itself in those who have consumed cannabis heavily for prolonged periods of time, often beginning in the teenage years and continuing daily or weekly.

In a 2011 study published in the journal Current Drug Abuse Reviews, the authors indicate that “in nearly all cases there is a delay of several years in the onset of symptoms preceded by chronic marijuana abuse.”

They also suggest that daily cannabis consumption was often more than three sessions in a given day. However, after a few weeks of abstinence from cannabis, symptoms go away in the majority of cases.

What causes cannabinoid hyperemesis syndrome?

cannabis leaf on hand
Several working theories have been floating around about what causes cannabinoid hyperemesis syndrome.

First proposed in 2004, over 175 cases of CHS have been identified in the clinical literature. However, exactly why CHS occurs in some consumers is not known.

As authors write in a 2016 review on the subject published in the Journal of Medical Toxicology:

“There are many suggested pathophysiologic mechanisms of CHS, though evidence for each is minimal.”

Some theorists suggest that patients have the herb’s primary psychoactive compound to thank for these devastating symptoms.

Tetrahydrocannabinol (THC), the molecule that causes the famous cannabis “high” may slow down gastrointestinal motility and prevent food from properly leaving the body. This backed-up food is hypothesized to trigger the body’s vomiting reflex in the brainstem.

Other theorists have a different take on the matter.

Some suggest that metabolites of THC and other molecules may build up in the fatty tissues of the brain, causing a toxic reaction.

Others still suggest that excessive cannabis use is also causing cell receptors that normally reduce nausea and vomiting to temporarily deactivate.

However, all of these theories are presented with only low-quality evidence thus far, making it difficult to determine what exactly is happening in these cases.

The only consistent risk factors seem to be prolonged weekly or daily consumption of high-dose cannabis. Yet, it is also important to recognize that these symptoms are not present in all chronic consumers.

The Medical Toxicology authors continue, ‘it is not clear why cannabis appears to suppress emesis under certain circumstances and induces it in others. It is also unknown why only some individuals develop CHS when the use of cannabis is so widespread.”

Is CHS real?

man not well
Many cannabis enthusiasts have strong reason to doubt CHS is real.

While a growing body of evidence suggests that cyclic vomiting is a very real condition that presents itself in some chronic cannabis consumers.

However, the newly defined pathology has received some criticism.

In 2006, Australian researchers published a letter regarding CHS in the journal Gut. They write,

“Cannabis has been consumed for many centuries and is currently used by millions of people in many countries. It is hard to believe that a distinctive syndrome caused by cannabis has never been noted before by users or clinicians.”

In addition, the authors suggest that there was no distinctive evidence that cannabis is the exact cause in this situation. They argue that the phrase “cannabinoid hyperemesis is “unduly presumptive.”

They continue, “some of these cases appeared to improve with abstinence and then relapsed when patients were “rechallenged” with cannabis, but neither the patients nor the authors appear to have been blinded in the rechallenge. The proposed biological explanation is weak.”

Unfortunately, data coming out this far seem to offer support for rather than deny the existence of cannabis-induced nausea and vomiting.

For example, a 2016 study published in Academic Emergency Medicine found that cases of cyclic vomiting emitted to the emergency department have significantly increased in the state of Colorado after adult-use cannabis legalization.

How to prevent cannabinoid hyperemesis syndrome

For those who have been diagnosed with CHS, avoiding cannabis is considered the most effective way to reverse symptoms.

However, for herb-lovers hoping to stay safe with the plant, there are a few things you can do to prevent unwanted nausea and vomiting.

1. Consume in moderation

The number one way to prevent CHS is to avoid heavy cannabis consumption. This means treating cannabis more like an occasional treat than a daily habit.

A joint following a weekend dinner? Excellent. Four joints a day, every day, for 15 years? Perhaps not as excellent for those concerned about CHS.

2. Take breaks

man resting on sofa
Taking a cannabis break could mean finding other activities to distract you.

If you have been consuming cannabis frequently, consider taking a break.

While “tolerance breaks” may not be beneficial for those who have been diagnosed with CHS, taking regular and prolonged periods of abstinence from the plant may be helpful in reducing the likelihood that you will develop a cannabinoid toxicity.

Though, to be clear, no research has specifically indicated that tolerance breaks are helpful in preventing CHS.  

3. Keep a journal

Many medical cannabis consumers rely on large daily doses of the plant as a part of their treatment plan.

Now that CHS is recognized as a more legitimate condition, it is of the utmost importance to work closely with a medical professional and monitor your symptoms and overall wellbeing with the plant.

Keeping a journal regarding what strain or products you are using, the brand, and the amount may be helpful in allowing you and your care team to better identify how best to utilize cannabis to meet your specific needs.

Recording any changes that occur over time, such as the sudden onset of stomach pain, may also provide a good indication of how well your cannabis medicines are working for you.

4. Save cannabis for later in life

The majority of cases of CHS involve individuals who began consuming the herb as teens or adolescents and then continued to consume for years into adulthood.

Research has shown that simply delaying the age in which you start consuming cannabis can drastically affect the likelihood of a person becoming dependant on the herb and consuming it in excess.


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