Although treatment for multiple sclerosis (MS) has advanced significantly in recent years, symptom management remains challenging, prompting many patients to seek alternative approaches such as cannabis for symptom relief. In a survey conducted by the National Multiple Sclerosis Society, 66% of respondents indicated that they currently use cannabis for this purpose.1
Medical cannabis use is now permitted in 30 states and Washington, DC.2,3 Because of conflicts between state and federal drug laws, there is no such thing as a medical cannabis prescription. Instead, patients must obtain certification from a physician who is approved to certify patients for participation in the program, based on one of numerous conditions, including MS. Once certified, patients receive a card that allows them to purchase medical marijuana from designated dispensaries.
With increasing legalization and social acceptance regarding the use of cannabis, it is anticipated that the number of people using it to manage symptoms of MS will increase as well. However, evidence supporting the benefits of cannabinoids varies widely in terms of quality and bias.
A 2018 systematic review examined randomized controlled trials pertaining to the symptoms with the strongest evidence base, including 2 that are relevant to MS: pain and spasticity.4 The authors found that patients taking cannabinoids were more likely to achieve pain reduction of at least 30%, with a risk ratio of 1.37 (95% CI, 1.14-1.64) and number needed to treat of 11. Most studies investigating the effects of cannabinoids on pain focused on neuropathic pain. In addition, a positive global impression of change in spasticity was observed (risk ratio 1.45; 95% CI, 1.08-1.95; number needed to treat=7). These specific benefits are recognized by the American Academy of Neurology as having strong supporting evidence.5
There is also “indirect evidence that reductions in spasticity, pain, and fatigue may result in improvements in the mobility of [people with] MS,” according to another recent paper.3 The authors further noted that cannabis use has been shown to reduce the intake of prescription drugs that have more numerous and serious side effects, including opioids, benzodiazepines, and antidepressants. Findings published in 2017, for example, demonstrated that 77% of frequent opioid users had reduced consumption since initiating cannabis use, and many patients also decreased their use of antianxiety (72%), migraine (67%), and sleep-promoting (65%) medications.6
To learn more about how medical cannabis is currently being used among patients with MS, Neurology Advisor spoke with Clyde E. Markowitz, MD, director of the Multiple Sclerosis Center at Penn Medicine and associate professor of neurology at the Hospital of the University of Pennsylvania, and Thorsten Rudroff, PhD, FACSM, assistant professor in the Department of Health and Exercise Science at Colorado State University, and adjunctive assistant professor in the Department of Radiology at the University of Colorado Medical School.
Neurology Advisor: What are some of the most pronounced benefits of cannabinoids for MS and how are they currently being used to treat MS symptoms?
Dr Markowitz: To date, the major active metabolites [identified] in medical marijuana are Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD), and these have been found to have benefits in individuals with MS, particularly regarding pain and spasticity. Whether there are other benefits is less proven. Animal data suggest immunomodulatory and neuroprotective effects, but these have not been adequately studied in humans.7,8
Dr Rudroff: Cannabinoids are effective for the treatment of pain and spasticity in people with MS. There is scientific evidence9 supporting the effectiveness of cannabinoids with a 1:1 ratio of CBD:THC, as noted during a recent meeting sponsored by the National Institutes of Health, Marijuana and Cannabinoids: A Neuroscience Research Summit, in 2016. People with MS are currently self-medicating with cannabis. There are no specific guidelines, so patients must figure out which cannabis product is best for them.