Multiple sclerosis (MS) is a chronic degenerative disease of the central nervous system that causes inflammation, muscular weakness and a loss of motor coordination. Over time, MS patients typically become permanently disabled and, in some cases, the disease can be fatal. According to the US National Multiple Sclerosis Society, about 200 people are diagnosed every week with the disease — often striking those 20 to 40 years of age.
Survey data indicates that patients with MS frequently turn to cannabis for symptomatic relief,[1-3] with some studies estimating that nearly one-in-two MS patients report current use of the substance.[4-5] Many of these patients report that their use of cannabis results in symptomatic improvements and allows them to reduce their use of prescription medications.[6]
Numerous studies, including randomized, placebo-controlled trials, affirm the safety and efficacy of either cannabis or whole-plant cannabis extracts in MS patients.[7-20] For example, in a clinical trial sponsored by the University of San Diego, “Smoked cannabis was superior to placebo in symptom and pain reduction in participants with treatment-resistant spasticity.”[21] In recent years, health regulators in numerous countries, including Canada, Denmark, Germany, New Zealand, Spain, and the United Kingdom have approved the prescription use of plant-derived cannabis extracts in patients with MS. Long-term use of these extracts has been shown to be safe and effective.[22] The administration of comparably low doses of plant-derived extracts has also been shown to be efficacious and well-tolerated in human trials.[23]
Preclinical models suggest that cannabinoids may also inhibit MS progression in addition to providing symptom management. Writing in 2003 in the journal Brain, investigators at the University College of London’s Institute of Neurology reported that administration of the synthetic cannabinoid agonist WIN 55,212-2 provided “significant neuroprotection” in an animal model of multiple sclerosis. “The results of this study are important because they suggest that in addition to symptom management, … cannabis may also slow the neurodegenerative processes that ultimately lead to chronic disability in multiple sclerosis and probably other disease,” researchers concluded.[24] Other researchers have reported similar findings, documenting that “the treatment of EAE mice with the cannabinoid agonist WIN55,512-2 reduced their neurological disability and the progression of the disease.”[25] The administration of plant-derived cannabinoids has also been shown to boost immune function in subjects with MS, suggesting a “disease-modifying potential of cannabinoids [for] MS” patients.[26]
Longitudinal trials also suggest that cannabis therapy may slow down the clinical progression of MS in humans.[27] Observational data from an extended open-label study of 167 multiple sclerosis patients concluded that the use of whole plant cannabinoid extracts relieves symptoms of pain, spasticity and bladder incontinence for an extended period of treatment (mean duration of study participants was 434 days) without requiring subjects to increase their dose.[28] Results from another two-year open-label extension trial report that the administration of cannabis extracts is associated with long-term reductions in neuropathic pain in select MS patients. On average, patients in that study required fewer daily doses of the drug and reported lower median pain scores the longer they took it.[29] Investigators have suggested that these results would be unlikely in patients suffering from a progressive disease like MS unless the cannabinoid therapy was halting its progression.
While there exists growing worldwide acceptance of the use of cannabis extracts for MS, not all patients respond to such treatments. However, in some instances, those non-responsive to extracts have responded favorably to herbal cannabis products.[30] These results emphasize that cannabis flower should remain a legal therapeutic option, even in jurisdictions where medical cannabis extracts are already available by prescription.
REFERENCES
[1] Clark et al. 2004. Patterns of cannabis use among patients with multiple sclerosis. Neurology 62: 2098-2010.
[2] Rudroff and Honce. 2017. Cannabis and multiple sclerosis: The way forward. Frontiers in Neurology 8: 299.
[3] Banwell et al. 2016. Attitudes to cannabis and patterns of use among Canadians with multiple sclerosis. Multiple Sclerosis and Related Disorders 10: 123-126.
[4] Reuters News Wire. August 19, 2002. “Marijuana helps MS patients alleviate pain, spasms.”
[5] Braley et al. 2020. Cannabisnoid use among Americans with MS: Current trends and gaps in knowledge. Multiple Sclerosis Journal – Experimental, Translational and Clinical 6 [open access journal].
[6] McCormack et al. 2019. Multiple Sclerosis and use of medical cannabis: A retrospective review evaluating symptom outcomes. Neurology 92 (Supplement).
[7] Kindred et al. 2017. Cannabis use in people with Parkinson’s disease and Multiple Sclerosis: A Web-based investigation. Complementary Therapies in Medicine 33: 99-104.
[8] Farzaei et al. 2017. Efficacy and tolerability of phytomedicines in multiple sclerosis patients: A review. CNS Drugs 31: 867-889.
[9] Chong et al. 2006. Cannabis use in patients with multiple sclerosis. Multiple Sclerosis 12: 646-651.
[10] Rog et al. 2005. Randomized, controlled trial of cannabis-based medicine in central pain in multiple sclerosis. Neurology 65: 812-819.
[11] Wade et al. 2004. Do cannabis-based medicinal extracts have general or specific effects on symptoms in multiple sclerosis? A double-blind, randomized, placebo-controlled study on 160 patients. Multiple Sclerosis 10: 434-441.
[12] Brady et al. 2004. An open-label pilot study of cannabis-based extracts for bladder dysfunction in advanced multiple sclerosis. Multiple Sclerosis 10: 425-433.
[13] Vaney et al. 2004. Efficacy, safety and tolerability of an orally administered cannabis extract in the treatment of spasticity in patients with multiple sclerosis: a randomized, double-blind, placebo-controlled, crossover study. Multiple Sclerosis 10: 417-424.
[14] Zajicek et al. 2003. Cannabinoids for treatment of spasticity and other symptoms related to multiple sclerosis: multicentre randomized placebo-controlled trial. The Lancet 362: 1517-1526.
[15] Page et al. 2003. Cannabis use as described by people with multiple sclerosis [PDF]. Canadian Journal of Neurological Sciences 30: 201-205.
[16] Wade et al. 2003. A preliminary controlled study to determine whether whole-plant cannabis extracts can improve intractable neurogenic symptoms. Clinical Rehabilitation 17: 21-29.
[17] Consroe et al. 1997. The perceived effects of smoked cannabis on patients with multiple sclerosis. European Journal of Neurology 38: 44-48.
[18] Meinck et al. 1989. Effects of cannabinoids on spasticity and ataxia in multiple sclerosis. Journal of Neurology 236: 120-122.
[19] Ungerleider et al. 1987. Delta-9-THC in the treatment of spasticity associated with multiple sclerosis. Advances in Alcohol and Substance Abuse 7: 39-50.
[20] Denis Petro. 1980. Marijuana as a therapeutic agent for muscle spasm or spasticity. Psychosomatics 21: 81-85.
[21] Corey-Bloom et al. 2012. Smoked cannabis for spasticity in multiple sclerosis: a randomized, placebo-controlled trial. CMAJ 10: 1143-1150.
[22] M. Trojano. 2016. THC:CBD observational study data: Evolution of resistant MS spasticity and associated symptoms. European Neurology 75: 4-8.
[23] Gustavsen et al. 2021. Safety and efficacy of low-dose medical cannabis oils in multiple sclerosis. Multiple Sclerosis and Related Disorders 48 [online ahead of print].
[24] Pryce et al. 2003. Cannabinoids inhibit neurodegeneration in models of multiple sclerosis. Brain 126: 2191-2202.
[25] de Lago et al. 2012. Cannabinoids ameliorate disease progression in a model of multiple sclerosis in mice, acting preferentially through CB(1) receptor-mediated anti-inflammatory effects. Neuropharmacology 62: 2299-2308.
[26] Killestein et al. 2003. Immunomodulatory effects of orally administered cannabinoids in multiple sclerosis. Journal of Neuroimmunology 137: 140-143.
[27] Pryce et al. 2015. Neuroprotection in experimental autoimmune encephalomyelitis and progressive multiple sclerosis by cannabis-based cannabinoids. Journal of Neuroimmune Pharmacology 10: 281-292.
[28] Wade et al. 2006. Long-term use of a cannabis-based medicine in the treatment of spasticity and other symptoms of multiple sclerosis. Multiple Sclerosis 12: 639-645.
[29] Rog et al. 2007. Oromucosal delta-9-tetrahydrocannabinol/cannabidiol for neuropathic pain associated with multiple sclerosis: an uncontrolled, open-label, 2-year extension trial. Clinical Therapeutics 29: 2068-2079.
[30] Secca et al. 2016. The use of medical-grade cannabis in patients non-responders to nabiximols. Journal of Neurological Sciences 15: 349-351.