Arthritis is a clinical condition characterized by joint pain. According to the Arthritis Foundation of the United States, there are more than 100 types of the disease, but common symptoms include swelling, pain, stiffness and loss of range of motion.

The most common type is called osteoarthritis, or degenerative joint disease, characterized by the wearing away of the protective cartilage at the ends of bones. Another type is known as rheumatoid arthritis, which is when the immune system mistakenly attacks healthy cells, including the synovial membrane that lines the joints. Other more common types include juvenile arthritis, which develops in children; psoriatic arthritis, which affects people with psoriasis; infectious arthritis, which is an infection that spreads to a joint; and gout, caused by the accumulation of uric acid.

The pain, swelling and stiffness associated with arthritis can vary in intensity and between individuals. A case of severe arthritis can cause severe chronic pain that affects the ability to perform everyday activities. Treatments for arthritis focus on relieving pain and swelling through medications, physical therapy and, in some cases, surgery.

Discoveries about the effects of cannabis on arthritis

Preclinical studies suggest that cannabis may help limit damage from different types of arthritis. In an animal study, cannabidiol (CBD), one of the main cannabinoids found in the plant, effectively blocked the progression of the disease. Researchers found that CBD protects joints against serious damage and concluded that the cannabinoid offers potent effects against arthritis 9.

Other studies have found that synthetic cannabinoids offer strong anti-inflammatory and immunosuppressive properties, reducing joint damage in mice with osteoarthritis 4, 9, 10. More recently, cannabinoid treatments have been found to be effective in reducing cartilage wear associated with osteoarthritis 7.

Research has also shown that cannabis can help manage the pain and inflammation associated with the disease. CBD and another important cannabinoid found in cannabis – tetrahydrocannabinol (THC) – activate the two main cannabinoid receptors (CB1 and CB2) of the body’s endocannabinoid system. Studies have shown that the cannabinoid receptor system present in joint synovium can be a therapeutic target, as it treats pain and inflammation associated with osteoarthritis and rheumatoid arthritis 6, 10. These two receptors regulate the release of neurotransmitters and the immune cells of the central nervous system to reduce pain 14. It was discovered that activation of the CB1 receptor significantly decreases sensitivity to pain in the knee joints of rats with osteoarthritis 10. A study found that medicines based on Cannabis significantly improved pain during joint movement, at rest and quality of sleep in patients with rheumatoid arthritis 3. Several preclinical studies have confirmed the anti-inflammatory and analgesic effects of cannabis, and support the idea that the endocannabinoid system is involved in relieving pain associated with arthritis 8.

Recent Studies on Cannabis for Arthritis

• Activation of CB2 receptors reduces osteoarthritic knee pain. Cannabinoid CB2 receptors regulate central sensitization and pain responses associated with osteoarthritis of the knee joint. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3840025/
• CBD has anti-inflammatory and immunosuppressive effects and can be a powerful medicine against arthritis. The non-psychoactive cannabidiol present in cannabis is a treatment for collagen-induced arthritis in murine rats. http://www.pnas.org/content/97/17/9561.full

Referências:

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3. Blake, D.R., Robson, P., Ho, M., Jubb, R.W., and McCabe, C.S. (2006, January). Preliminary assessment of the efficacy, tolerability and safety of a cannabis-based medicine (Sativex) in the treatment of pain caused by rheumatoid arthritis. Rheumatology, 45(1), 50-2. Retrieved from
   https://academic.oup.com/rheumatology/article-lookup/doi/10.1093/rheumatology/kei183.
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   https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4243420/.
7. Kong, Y., Wang, W., Zhang, C., Wu, Y., Liu, Y., and Zhou, X. (2016, June). Cannabinoid WIN‑55,212‑2 mesylate inhibits ADAMTS‑4 activity in human osteoarthritic articular chondrocytes by inhibiting expression of syndecan‑1. Molecular Medicine Reports, 13(6), 4569-76. Retrieved from
   https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4878569/.
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