CBD Oil and Medical Marijuana

Reviewed by: HU Medical Review Board | Last reviewed: August 2023

The cannabis plant has been used in a variety of ways for thousands of years, and cannabis and its derivatives are being looked at as a potential therapy for inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn’s disease (CD). However, more research is needed—particularly large-scale trials that are randomized and double-blinded, meaning neither the doctors nor the patients know if they are getting the actual treatment or a placebo—before cannabis can be justified as a proven therapy for IBD.1

Traditionally, the smoking form of cannabis has been called marijuana, although some oral formulations are now also called marijuana. However, cannabis for recreational or medicinal use is illegal by federal law. Contrary to the federal policy, several individual states have passed laws making medical marijuana legal, and a few states have also made recreational use of marijuana legal.1 Each individual should consult with their doctor and the laws of the state they reside in before considering the possibility of using medical marijuana.

Why do people with inflammatory bowel disease use medical marijuana?

As with other complementary and alternative practices, some people with IBD use cannabis if other medications or treatment options haven’t relieved their symptoms—particularly symptoms of pain, nausea, and lack of appetite—as well as to improve their overall mood. Some people with IBD turn to complementary and alternative practices like medical marijuana because it gives them a sense of control over their disease, by giving them something that they can actively do to combat their symptoms. Others feel that options like medical marijuana may have less side effects than other treatments. However, there haven’t been enough research studies conducted on cannabis in people with IBD to fully evaluate the safety and potential risks.1

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How common is the use of medical marijuana in people with inflammatory bowel disease?

There are no widespread studies that have been conducted to determine how many people with IBD use marijuana, and such studies remain difficult considering the illegality of cannabis in many states. However, there are a few studies that shed some light on the use of cannabis in IBD:

  • A 2007 study from Spain that surveyed 214 patients with IBD found that nearly 10% used some form of cannabis.2
  • In 2011, a Canadian study that evaluated 291 patients with IBD found that among people with UC, 50.5% reported use during their lifetime and 11.6% were current users of cannabis. Among people with CD, 48.1% had used it during their lifetime and 15.9% were current users. Between 33–50% of those who had used cannabis at some point in their lifetime reported using medical cannabis specifically for the relief of symptoms of IBD.3
  • A study in the U.S. in 2013 surveyed 292 patients with IBD and found that 12.3% actively used marijuana, and 32% of lifetime users stated they used marijuana to help control IBD symptoms.4

While these studies use self-reported data, cannabis is being used by people with IBD, and patients report that cannabis helps their symptoms of abdominal pain, nausea, and diarrhea. However, these results have not been confirmed by measuring inflammatory markers or biopsies of intestinal tissue.1

What is CBD oil?

The active compounds in the cannabis plant are called cannabinoids. The two most well-known cannabinoids are THC (delta-9-tetrahydrocannabinol) and CBD (cannabidiol). THC has been associated with reduction of nausea and pain, increased appetite, and psychological effects like euphoria and altered sensory perception, which can make users feel “high” or intoxicated. CBD does not produce intoxicating effects, but it produces sedative effects that can help reduce convulsions, nausea, and inflammation.5,6 CBD oil contains all or mostly CBD, with little to no THC included; however, there are a variety of preparations with varying doses of CBD and THC.

How does CBD oil or medical marijuana work in the body?

Researchers have discovered that the human body has an endocannabinoid system (ECS). (“Endo” means internal or within the body.) The ECS is distributed throughout the body and plays a part in regulating many functions, including pain, mood, appetite, and the movement of the gastrointestinal system. The ECS is comprised of the cannabinoids the body produces, the receptors on which they act, and the enzymes that are involved. The ECS receptors are cannabinoid 1 and 2 (CB1 and CB2), and both CB1 and CB2 are found in all layers of the intestines. THC and CBD have similar shapes to the internal cannabinoids and work on the same receptors.1,5

Using biopsy tissue from people with IBD, results from one study suggest that people with IBD may have lower levels of the natural or internal cannabinoids, which may play a role in the chronic inflammation that is characteristic of IBD. This study only evaluated 41 people with CD and 33 people with UC, so with the small number of patients, additional research is needed to confirm these results. However, it does provide information on how cannabinoids are important in gut function and may offer a potential target for treatment.1

What are the risks of using CBD oil or medical marijuana?

The long-term negative effects of CBD oil or medical marijuana are not known. Few studies have been conducted on the long-term safety of cannabis, and those that have been completed are conflicting or are of poor quality. The medical field has identified several potential complications, including psychological addiction, a lowering of IQ, impaired immune function, decreased fertility, increased risk of motor vehicle accidents, and psychological issues like anxiety, paranoia, and psychosis.1,5

The short-term side effects of cannabis are better understood and include temporary impairment of short-term memory and concentration, increase in anxiety or paranoia, lowered blood pressure, increased heart rate, and impaired motor skills.5

Most of the psychotropic effects from medical marijuana are seen with THC.

In addition to the known and potential risks of using medical marijuana, there is the potential that medical marijuana might help to relieve some symptoms of IBD without actually treating the underlying disease (i.e. the chronic inflammation).1

What are the challenges with medical marijuana?

With cannabis being illegal nationally in the U.S., there has been a lack of funding for research, as well as concerns about the legality of research. More research is needed to fully understand the potential risks and benefits of cannabis in diseases like IBD.

The illegality of medical marijuana also means there is no oversight or regulation on quality. Without any regulation, various products available to consumers could contain potentially dangerous ingredients, and the levels of THC and CBD can vary greatly in different preparations.1,5