Despite the extraordinary progressions in cannabis medicine and the necessary push for changes to its legislation, advocates should not be blind to the very real – and often serious – complications of excessive cannabis use. As they say, too much of anything is good for nothing.
Holding an unreservedly positive view of this plant allows us only to overlook any unwanted effects, which would actually do far more harm than good. We’re here to help you better understand cannabis hyperemesis syndrome – a rare, but damaging, potential side effect of using cannabis.
What is cannabis hyperemesis syndrome?
Cannabis hyperemesis syndrome, or CHS for short, is a condition that occurs in people with a long history of cannabis use. It is characterised by:
- Abdominal pain
Taking regular hot showers or baths as a way to soothe nausea is another indicator of having CHS.
The symptoms of CHS can be grouped into three separate phases. The first is the prodromal phase, where the individual experiences nausea, abdominal discomfort, and potentially anxiety due to a fear of vomiting. The second is the hyperemetic phase, characterised by vomiting, dehydration, and weight loss. In the days or months following cannabis cessation is the recovery phase, where CHS symptoms subside.
Due to CHS being a relatively newly discovered condition, first documented in 2004, there hasn’t been a huge amount of research into its causes or potential treatments. So far, the only proven way to fully eliminate CHS symptoms is to stop using cannabis.
What causes it?
The only known cause of CHS is frequent, long-term cannabis use. CHS is most common in early middle-aged adults who use cannabis at least once a week and have done since adolescence. A review, published in 2017, found that 97% of patients with CHS use cannabis at least weekly, with 75% doing so for over a year.
Since it only affects a small proportion of regular users, it is thought that genetics play a role in CHS symptom onset, but there is no conclusive evidence to support this idea.
Exactly how cannabis might induce chronic nausea and vomiting isn’t fully known, but one theory suggests that it is a result of the overstimulation of cannabinoid receptors in the endocannabinoid system (ECS).
The ECS is a complex cell-signalling network that spans the entire brain and body. By coordinating a myriad of biological functions, the ECS acts as our universal regulator; it aims to keep every bodily system in balance. It does this through the activity of cannabinoid (CB) receptors, which are modulated by the signalling of either endocannabinoids or plant-derived cannabinoids.
THC and CBD – the two major cannabinoids in the cannabis plant – can activate CB receptors, both directly and indirectly. Since the ECS also plays a prominent role in digestion and gut function, chronic exposure to these cannabinoids is likely to overstimulate CB receptors in the gastrointestinal tract and, in turn, induce nausea and abdominal pain.
Isn’t cannabis used to treat nausea?
Cannabis has shown to be hugely effective at managing nausea and stimulating appetite. In one recent study, published in the Journal of Clinical Gastroenterology this month, researchers investigated the effects of cannabis self-administration on nausea symptoms in 886 participants across 3 years. They found that, on average, 96% of patients reported nausea relief within one hour of using cannabis.
Since many people rely on this therapeutic benefit of cannabis, the risk of developing CHS may spark concern in some users – allow us to explain. Both THC and CBD are biphasic; they have opposite effects at low and high doses. It’s therefore likely that occasional low doses can be used to relieve nausea but chronic THC exposure may worsen nausea. This would explain why CHS tends to only occur in heavy, long-term cannabis users.
CHS: diagnosis, treatment, and support
The diagnosis of CHS isn’t often straightforward. This is likely because, in regions with legal restrictions on THC, patients aren’t usually entirely honest about their cannabis use to medical professionals. However, this could also be because many doctors don’t receive adequate training on the effects of cannabis – both positive and negative.
To overcome this issue, a group of researchers have proposed diagnostic criteria for CHS, which involves three categories of symptoms:
- The essential criteria for diagnosis
- Over a year of cannabis use
- Major features
- Weekly cannabis use
- Severe, recurring nausea and vomiting
- Symptoms that resolve when the person stops using cannabis
- Symptoms relief with hot showers or baths
- Supporting features
- Younger than 50 years old
- Significant weight loss (>5 kg)
- Normal bowel habits
Other than cannabis cessation, there is no known cure for CHS. There are, however, some medications that doctors may be able to prescribe for symptom relief. These could include pain relief medications, IV fluid replacement, anti-sickness medicines, or capsaicin cream.
If a person continues to use cannabis despite experiencing CHS symptoms, this could lead to potentially life-threatening complications. According to the NHS, these could include muscle spasms, seizures, kidney failure, or heart rhythm abnormalities, among others. In rare cases, CHS could even cause death as a result of hyponatremic dehydration (low sodium levels).
It is, however, important to acknowledge that cannabis cessation is often not as simple as “just stopping”. Although it is an inherently non-addictive substance, cannabis can still be abused. And since the psychological aspect of addiction can be just as challenging as physical dependence, this makes breaking a behavioural habit considerably difficult.
People who begin using cannabis as teenagers are between 4 to 7 times more likely to become dependent than those who started in adulthood. As most patients with CHS also started using cannabis in adolescence, this heightened risk of psychological dependence can make quitting even harder.
Whatever your reason for wanting to quit cannabis, CHS or not, support is available. It is not uncommon to experience mild withdrawal symptoms when you stop using cannabis, which could include:
- Problems sleeping
- Strange dreams
- Irritability and mood swings
- Cravings for cannabis
Withdrawals aren’t pleasant, but they do get better with time, and it’s much easier to get through them with support from family, friends, or professionals. Withdrawal symptoms can also be made easier with small changes to your daily routine. Prioritising calming habits in the evenings, such as having a warm bath, reading, or practising mindfulness, can massively help to boost your mood. Similarly, waking up and going to bed at the same time each day can be a huge help when trying to improve your sleeping pattern.
Cannabis is a powerful plant that is improving – even saving – the lives of thousands of people over the world. Whilst it does have immeasurable therapeutic potential, it’s clear that cannabis definitely isn’t for everyone.
If you feel that you, or someone close to you, is struggling with cannabis hyperemesis syndrome, do not hesitate to contact a medical professional. For tips for quitting and further support, please see here.