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Cannabis has been used medicinally and recreationally for over 5000 years. It is a complex plant, which contains over 500 chemical components. Of these, at least 100 are unique to the cannabis plant – the cannabinoids. The plant-derived cannabinoids are termed phytocannabinoids. The major phytocannabinoids, and those we know most about, are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). THC possesses psychoactive effects, while CBD is non-psychoactive (i.e. it does not alter perception or consciousness).
The biological activity is mainly linked to the major cannabinoids THC and CBD. However, it is becoming clear that a wider range of cannabinoids and other constituents of the cannabis plant may be involved in its various therapeutic effects. These include the cannabinoids tetrahydrocannabivarin (THCV), cannabichromene (CBC), and cannabigerol (CBG). These minor cannabinoids are thought to subtly modulate or enhance biological effects when taken therapeutically.
The other main compounds in cannabis are the terpenes. These are aromatic compounds which give cannabis varieties distinctive smells and tastes. Terpenes may have additive therapeutic action, meaning they may work together with cannabinoids to modify or enhance medicinal effects. To date, more than 120 different terpenes have been identified in cannabis. Unlike cannabinoids, all major terpenes present in cannabis (e.g. myrcene, alpha-pinene, and beta-caryophyllene) can be found abundantly in nature. It is thought that the terpenes work together with cannabinoids to modify or enhance their effects. This is known as the “entourage effect”.
The human brain and other organs contain naturally-occurring cannabinoid (CB) receptors and the chemicals that bind to them. This is called the human endocannabinoid system (ECS). The role of the ECS is to maintain our body’s ability to function normally by influencing the functioning of other systems. It plays a critical role in our nervous system and regulates multiple physiological processes. This includes the adjustment of our response to pain, appetite, digestion, sleep, mood, inflammation, and memory. The ECS also influences seizure thresholds (i.e. in epilepsy), coordination, and other processes such as the immune system, heart function, sensory integration (touch, balance, sense of space), fertility, bone physiology, the central stress response system (the HPAA), neural development, and eye pressure.
There is ongoing clinical research supporting the use of medicinal cannabis in many conditions including:
- Chronic pain, particularly pain associated with the nervous system;
- Nausea, loss of appetite, weight loss, and vomiting associated with chemotherapy or radiotherapy used in the treatment of cancer, and anorexia and cachexia in HIV/AIDS;
- Pain and muscle spasms or cramps associated with multiple sclerosis or spinal cord damage;
There is also ongoing research on its use in epilepsy (particularly the drug-resistant childhood epilepsies), Gilles de la Tourette syndrome, therapy-resistant glaucoma, fibromyalgia, post-traumatic stress disorder, sleep disorders, bladder dysfunction, symptoms of Parkinson’s disease, and depression.
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