MS is a neurological disorder characterized by loss of the protective myelin sheath on neurons in the central nervous system (CNS), which impairs their function and leads to cell death. This degeneration of the CNS causes many symptoms, most notably movement issues such as muscle spasms and loss of coordination, as well as pain, vision loss, and bowel issues. The medicinal properties of cannabis make it a suitable option for treating this disease. In fact, the pharmaceutical product Sativex was the world’s first prescription medicine made from the cannabis plant, and was approved for the primary purpose of treating spasticity associated with multiple sclerosis. Sativex contains about equal amounts of tetrahydrocannabinol (THC) and cannabidiol (CBD), the two primary cannabinoids in cannabis. Several full-scale clinical trials led to its approval and confirmed further efficacy.
The first Phase 3 double-blind, placebo-controlled trial was published in 2011 and found Sativex was effective in reducing spasticity when used as add-on therapy to standard medications. Almost 75% of patients in the cannabis group experienced a 30% improvement, along with better sleep. Four years later, another double-blind, placebo-controlled trial confirmed the benefit of Sativex on spasticity. Yet further, an overview of a decade of clinical evaluations and post-marketing studies, which was published in 2017, determined that Sativex was effective for MS spasticity as well as improving quality of life.
Supporting Preclinical Evidence
Interest in cannabinoids for the treatment of MS has been driven by patient reports of efficacy as well as strong preclinical evidence. A review article published in 2006 by Spanish researchers described several attributes of cannabinoids that would theoretically allow them to benefit MS, including their ability to reduce the expression of pro-inflammatory cytokines (cell signaling proteins) that increase inflammation. Since MS is largely driven the immune system’s attack on neurons, options that can reduce inflammation are paramount for slowing its progression. Cannabinoids are also neuroprotective and may prevent the death of neurons, which at some point becomes irreversible and causes more advanced symptoms in MS.
A 2015 study specifically looked at a “Sativex-like” combination of cannabinoids in the treatment of a mouse model of MS. Extracts of predominantly THC and CBD, known as botanical drug substances (BDSs) because they derive from cannabis and feature a full-spectrum of other cannabinoids, were administered alone and in combination to mice after the development of MS-like symptoms. The combination produced several beneficial effects, including reduced inflammation and less damage of neurons. There was some restoration of myelin as well, which is important given the role of myelin loss in exacerbating MS. Another aspect of MS is the accumulation of chondroitin sulfate proteoglycans (CSPGs) in the spinal cord; while CSPGs are important structural components of human tissue, they can also contribute to inflammation and inhibit regeneration of neurons. The cannabinoid combination was effective in reducing CSPGs, which may have contributed to some of the anti-inflammatory effects. When THC-BDS and CBD-BDS were tested by themselves, CBD-BDS alleviated motor deterioration about as well as both cannabinoids combined. THC-BDS also worked but was reportedly weaker. As isolated cannabinoids, both THC and CBD have been shown to reduce production of proinflammatory cytokines like IL-6 and IL-17, which are involved in the pathogenesis of MS. CBD specifically can also significantly increase levels of the anti-inflammatory cytokine IL-10; therefore, cannabinoids appear to exert a dual action on inflammation by suppressing inflammatory mediators and boosting anti-inflammatory mediators.
New Results from a 2020 Trial
There is still more to learn about the effects of cannabis on other symptoms of multiple sclerosis, and to this end, trials continue to be conducted. A recent study published December 2020 in the journal Multiple Sclerosis and Related Disorders examined the effects of THC-rich, CBD-rich, and THC + CBD products for treating MS symptoms. The average doses consumed in the study ended up being 4mg THC and 7mg CBD, primarily given at once in the evening. Even with these low doses, significant benefits were reflected by decreased scores on various symptom scales. On average, pain decreased from 7 to 4, spasticity decreased from 6 to 2.5, and sleep disturbance decreased from 7 to 3. The authors concluded, “Treatment with medical cannabis oils was safe and well tolerated, and resulted in a reduction in pain intensity, spasticity and sleep disturbances in MS patients. This suggests that medical cannabis oils can be used safely, especially at relatively low doses and with slow titration, as an alternative to treat MS-related symptoms when conventional therapy is inadequate.”
Summary
There is no doubt that cannabis can help MS patients due to the strength of the existing evidence. However, more trials are still needed to examine the impacts of higher doses of THC and CBD, as well as the potential value of other phytocannabinoids like CBG, THCA, and CBDA. As physicians and pharmaceutical companies become more open to the use of medical cannabis, this research will doubtless take place eventually.
