Chemists have identified over 400 natural compounds in the cannabis plant, but when discussing its medical applications, two compounds in particular receive the lion’s share of attention: THC (tetrahydrocannabinol; pronounced tetra-hydro-ca-NA-bi-nall) and CBD (cannabidiol; pronounced ca-na-bi-DYE-all).

Just as each of us has a circulatory system to move blood and nutrients through our bodies and an immune system to defend against infection, we also have an endocannabinoid system. Although it occupies many parts of the body, the highest concentration is in the brain. The system affects a broad spectrum of physical processes, such as mood, pain perception, appetite and immune responses.

Both THC and CBD are cannabinoids, meaning they can bind to certain receptors in the endocannabinoid system, and alter the typical manner in which cells (particularly nerve cells in the brain) “talk” to one another. This marvellously complex communication process results in a wide range of physical phenomena, from regulating our immune systems to actually forming our thoughts.

THC is the chemical that causes the mind and/or body “high” commonly associated with cannabis consumption. The amount of THC in medical cannabis can vary widely, typically from just under 10% to over 30%. In addition to its psychoactive effects, it’s thought that THC may block the neural pathways that carry pain signals. Also, some studies suggest THC is a much more effective anti-inflammatory than commonly prescribed drugs such as aspirin and cortisone. This has led many healthcare practitioners to recommend THC-rich strains to patients with nerve-related pain.

Paradoxically, some of the characteristics associated with the euphoric cannabis experience have significant benefits for relieving symptoms of disease. The stimulation of appetite (the “munchies”) for example, is ideal for someone suffering side effects of chemotherapy or AIDS-related wasting syndrome. The impairment of memory and the sleep-inducing effects of THC may be desirable for treating symptoms of post-traumatic stress disorder (PTSD). There is also research being done on using THC to treat cancer, Alzheimer’s disease and common sleep apnea.

CBD is generally considered non-psychoactive—it doesn’t get you “high.” This has led many patients and healthcare practitioners to choose CBD oils and CBD-rich cannabis flowers to relieve symptoms while avoiding (or minimizing) the altered consciousness that some consider undesirable.

Certainly the most well-publicized application of CBD has been as an anticonvulsant in the treatment of certain severe forms of epilepsy. In part because of its extremely low toxicity and lack of psychoactive effects, it has been administered to epileptic children, notably in the case of Charlotte Figi, who was featured in a 2013 television documentary. (A high-CBD/low-THC extract called Charlotte’s Web was developed and named for her.) There is also growing acceptance of CBD to reduce or eliminate the tremors associated with multiple sclerosis, Parkinson’s disease and certain spinal cord injuries. 

Although purified CBD extracts have shown significant promise as effective medicine, test results from studies of isolated THC (such as the synthesized version called Marinol) have so far been inconclusive. But since consuming THC-rich products derived from whole cannabis flowers has provided relief to so many patients, some medical cannabis advocates have suggested the “entourage effect” may be responsible for the difference. The entourage effect speculates that therapeutic properties are expressed most effectively only when THC is allowed to interact with other compounds present in the cannabis flower. Studies are underway to examine whether this is indeed the case, and—if so—which compound or compounds are involved. In the meantime, patients seeking therapeutic effects from THC-rich medicine may want to opt for smoking, vaporizing or consuming edibles derived from whole cannabis flowers.

CBD and THC are only two of the at least 104 cannabinoids so far identified in the cannabis plant. What, if any, health benefits these other cannabinoids may have will require much more research. In the meantime, if you’re considering medical cannabis as a treatment option, be sure to consult with your Licensed Producer and your healthcare practitioner, who will be glad to advise you on which existing strains and consumption methods may be best for you.                

For more information:

From the Canadian AIDS Society
HIV/AIDS and the Therapeutic Use of Cannabis
Cannabis as Therapy for People Living with HIV/AIDS: “Our Right, Our Choice

From the Arthritis Society
Position Paper: Medical Cannabis
Medical Cannabis—A Guide to Access

From Canadians for Fair Access to Medical Marijuana
Getting Started

From Wellness Soldier
Information on Medical Marijuana