Crohn’s disease is a type of inflammatory bowel disease that is believed to be caused by a combination of bacterial, immunological and environmental factors. The disease is progressive and incurable, and causes a range of severe and debilitating symptoms. Substantial evidence indicates that cannabis can help to manage symptoms.
Inflammatory processes are the primary mechanism of Crohn’s disease. The disease may affect any part of the gastrointestinal (GI) tract from the mouth to the anus, but the most commonly affected areas are the colon and the ileum (the large and small intestine), particularly the terminal section of the ileum that connects to the colon. Patches of chronic inflammation can lead to diarrhoea, bleeding and tearing of the GI tract lining, and bowel obstructions. In severe cases, portions of the intestine may need to be removed entirely.
Cannabis is used as a means of self-medication by a significant proportion of Crohn’s sufferers, and is anecdotally reported to provide substantial subjective improvements to the majority of symptoms, including inflammatory pain. Inflammation is well-known to be regulated by the endocannabinoid system, which—as the gut contains very high levels of cannabinoid receptors—has a fundamental role to play in inflammatory diseases of the GI tract.
In various studies, use of exogenous cannabinoids including ??-THC and CBD has been shown to activate the cannabinoid receptors of the GI tract and assist in the reduction of chronic inflammation. Both CB1- and CB2-receptors are present in the GI tract; the latter are usually less common than the former, but are present in far greater concentrations in individuals suffering from inflammatory bowel disease. It has been postulated that the CB2-receptors have an important role to play in modulating inflammatory pain, particularly that originating in the gut.
Diarrhoea is the most common primary symptom of Crohn’s disease. Depending on what part of the GI tract is affected, the stool may be mixed with mucus, pus or blood, and may be more or less watery. A sensation of urgency to defecate is common, along with a sensation of incomplete evacuation (known as tenesmus).
Cannabis has been used to treat diarrhoea for millennia, and modern research has provided empirical evidence of its efficacy. Crohn’s sufferers are thought to experience diarrhoea due to inflammation of the intestinal mucosa (the mucous membrane that lines the GI tract), as well as increased fluid secretion, reduced ability to absorb fluid, and presence of bacterial agents. Cannabis may ease symptoms of diarrhoea in Crohn’s due to its antibacterial properties, as well as its anti-inflammatory effects.
Activation of the CB1-receptors in the GI tract may also play an important role in improving symptoms of diarrhoea by reducing intestinal motility and fluid secretion; it is believed that this occurs through inhibition of acetylcholine released from the enteric nerves (i.e. those found in the peripheral nervous system, which helps regulate the GI tract). Acetylcholine, a neurotransmitter with a wide range of important functions, is well-known to increase peristalsis (gut motility).
Up to 70% of Crohn’s sufferers suffer from chronic pain. In the early stages of terminal ileitis (the form of Crohn’s that affects the terminal ileum), pain in the lower right side of the abdomen is common, and is often mistaken for appendicitis. Pain is generally a result of chronic inflammation, but may be a result of tearing or denudation of the intestinal lining, abdominal distention or bowel obstructions.
Cannabis may help improve symptoms of pain in Crohn’s sufferers by directly acting to reduce inflammation, by reducing the severity of abdominal distention, and by easing the symptoms of diarrhoea through reduction of gut spasms and inhibition of fluid release.
Although no formal studies into the effects of cannabis use on Crohn’s-related pain have been conducted thus far, there have been several questionnaires and surveys of patients, who have reported significant improvements in management of chronic pain. A pilot study conducted in California in 2005 questioned 12 Crohn’s sufferers on their perception of various major symptoms before and after commencing use of cannabis. Cannabis use was reported to improve all evaluated signs and symptoms, including pain—which was reported to rank up to 6.5 out of 10 on a subjective scale of severity prior to cannabis use, and just 2 out of 10 subsequent to cannabis use.
Appetite stimulant (orexigenic)
The aforementioned pilot study also found that patients reported a marked improvement in appetite when using cannabis, from approximately 1 out of 10 to almost 7 out of 10 on the scale. Appetite loss is a common symptom of Crohn’s, and often occurs as a result of chronic nausea and abdominal pain. Severe appetite loss can lead to dramatic unintentional weight loss in particularly bad flare-ups. As well as improving appetite, cannabis use led to less frequent defecation due to its influence on gut motility; these two factors combined caused the majority of patients to achieve weight gain after commencing use of cannabis.
Cannabis use can increase appetite in Crohn’s sufferers by reducing abdominal pain and inhibiting excessive peristalsis; however, it also helps to increase sensations of hunger by directly agonizing certain receptors in the GI tract that usually respond to the presence of ghrelin (an important ‘hunger hormone’ that has also shown signs of being a useful treatment for Crohn’s).
Various studies have shown that presence of ghrelin or cannabinoid agonists such as THC cause increased production of an enzyme—AMP-activated protein kinase (AMPK)—in the hypothalamus. The enzyme is crucial to the metabolic processes that regulate energy homeostasis (energy balance) in the body, and is produced in response to stimulation of the GHS-R1a ghrelin receptors found in the GI tract. Thus, THC can effectively do the job of ghrelin by activating the receptors and directly stimulating the brain to produce sensations of hunger.