Some literature reviews have provided a general overview of the available data on the role of cannabinoids in the treatment of MS symptoms.
Together with disease modifying medicines and corticosteroids for the treatment of relapses, interest in symptomatic treatments is increasing in the field of research on multiple sclerosis therapies.
With regard to symptomatic pharmacotherapies, there is limited evidence supporting efficacy; however, complementary therapies are quite widespread among patients.
In this context, cannabis-based medicinal products have provided encouraging indications in terms of improving multiple sclerosis symptoms.
A descriptive analysis of the literature [1], published by a group of researchers in the UK, took stock of the current knowledge and available data on the efficacy and safety of cannabis-based medicinal products for the symptomatic treatment of multiple sclerosis.
Effects on spasticity
A recent Cochrane collaboration review [2] identified and analysed 4 studies that compared some cannabinoids with placebo in patients with multiple sclerosis: the conclusions indicate that cannabis-based products may increase the number of patients reporting a significant reduction in the perceived severity of spasticity up to 14 weeks. Specifically, treatment with a combination of CBD and delta-9-THC in spray form and with a cannabis extract for oral use is associated with a 2.5 times higher chance of achieving a clinically significant improvement in spasticity, without an increase in severe adverse effects compared to the placebo.
With regard to the cannabis extract, a study conducted in 22 centres in the United Kingdom on 277 patients in total compared the efficacy of the extract with placebo in patients with multiple sclerosis. Patients in the treatment group reported significantly greater improvements in spasticity than the placebo group, with the effect increasing over time. The response rate was 30.8% in the patients treated with cannabis compared to 13.4% of the control group.
At the moment, the combination of CBD and delta-9-THC in spray form is the most studied cannabinoid product in the field of multiple sclerosis and is approved in several countries for the treatment of neuropathic pain and treatment-resistant spasticity [3].
Clinical practice data have also confirmed its usefulness as an adjunctive treatment to other therapies normally used against spasticity, which, however, according to available data, a significant proportion of patients develop resistance to.
With regard to other cannabis-based products, efficacy trials in the treatment of spasticity are limited. What is more, further studies would be required since the common adverse effects of the CBD- and delta-9-THC based product, such as dysgeusia, oral pain and irritation at the administration site, promote discontinuation of treatment. Therefore, the authors of the analysis [1] suggest considering other cannabinoids with a balanced ratio of CBD to delta-9-THC in patients who have achieved improvements but have poor tolerability.
The Australian guidelines for the use of medical cannabis in multiple sclerosis concerning spasticity refer to some literature reviews that point to the likely efficacy of cannabinoids in reducing this symptom [4]. Specifically, with regard to THC:CBD extracts, the document reports the results, although not entirely consistent, obtained by 6 studies, including 5 randomised controlled trials, which prove their efficacy in disease-related spasticity.
Effects on pain
Few clinical trials have investigated the effects of cannabis-based products on pain outcomes in multiple sclerosis patients. Research conducted in neurophysiology indicates that the combination of CBD and delta-9-THC in spray form may improve the sensory response, with a mechanism that provides a rationale for potential analgesic effects [3].
With regard to clinical data, a Cochrane collaboration review [2] concluded, based on the results of a study on 48 patients, that cannabinoids may increase the number of subjects reporting a significant reduction in the perceived severity of chronic neuropathic pain compared to placebo.
Other literature data [1] indicated that taking cannabinoids orally or sublingually is associated with a 10% increase in the number of patients reporting a clinically significant pain reduction compared to the placebo group.
These results have been confirmed by the data from the UK Medical Cannabis Registry on 190 patients, which indicate significant improvements in patient reported outcomes relating to the severity of pain and interference in daily life, also confirmed in subjects treated with a specific CBD oil and delta-9-THC preparation.
Furthermore, a randomised, double-blind, placebo-controlled trial conducted on 66 patients with multiple sclerosis and central neuropathic pain concluded that a medicinal product based on whole dried flos in spray form, containing THC (2.7 mg) and CBD (2.5 mg), is effective and safe in reducing pain and sleep disorders, in addition to standard analgesic therapy [5].
Effects on psychiatric symptoms
So far, there has been little investigation into the efficacy of cannabinoids on anxiety and mood disorders in multiple sclerosis [1].
The data obtained in small case series, albeit confirmed by data from the UK Medical Cannabis Registry, point to the possibility that treatment with cannabis-based products leads to improvements in anxiety symptoms in patients with multiple sclerosis and generalised anxiety disorder.
Cannabinoids and multiple sclerosis: yes or no?
“Although further high-quality, randomised, controlled trials are required, the available data are promising with regard to the usefulness and tolerability of cannabis-based products in the treatment of multiple sclerosis symptoms in people who have not had a sufficient clinical response to first-line therapies,” is the British researchers’ conclusion.
Reference
- Erridge S, Sodergren MH, Weatherall MW. Medical cannabis in multiple sclerosis. British Journal of Neuroscience Nursing 2022;18(Sup3):S28-S31
- Filippini G, Minozzi S, Borrelli F, et al. Cannabis and cannabinoids for symptomatic treatment for people with multiple sclerosis. Cochrane Database Syst Rev. 2022 May 5;5(5):CD013444.
- Cristino L, Bisogno T, Di Marzo V. Cannabinoids and the expanded endocannabinoid system in neurological disorders. Nat Rev Neurol 2020;16(1):9-29.
- Guidance for the use of medicinal cannabis in the treatment of multiple sclerosis in Australia. Available at: https://www.tga.gov.au/resources/resource/guidance/guidance-use-medicinal-cannabis-treatment-multiple-sclerosis-australia
- Rog DJ, Nurmikko TJ, Friede T, Young CA. Randomized, controlled trial of cannabis-based medicine in central pain in multiple sclerosis. Neurology 2005;65(6):812-9.
