New Review Finds Cannabis Could be a Promising Treatment For Multiple Sclerosis
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A new review of research of cannabis and multiple sclerosis (MS) has concluded that medical cannabis formulations demonstrate reasonable efficacy in improving muscle spasms, pain, and sleep-related quality of life for those with MS, with the benefits beginning after just weeks of treatment.
With some of these benefits remaining past the six- or twelve-month mark, the review authors recommend that more long-term studies be done on medicinal cannabis formulations for MS.
In addition, the authors from Kean University, New Jersey, and Saint James School of Medicine, Illinois, say that more studies should be carried out that focus on exploring the molecular mechanisms behind cannabis’ apparent effectiveness, such as its ability to inhibit neuroinflammation and promote healing in the central nervous system.
Medical cannabis formulations improve quality of life
The literature review surveyed human and animal studies from 2007 onwards, which focused on the use of CBD and THC formulations in human MS or in similar animal models of the disease, such as experimental autoimmune encephalomyelitis (EAE). After screening for eligibility, the review was left with 28 studies for examination, 14 human and 14 animal studies.
The majority of the human studies focused on the use of Sativex, an oromucosal spray containing a 1:1 ratio of THC and CBD. The spray has been approved for use in the United Kingdom, European Union, and Canada for the treatment of MS-related muscle spasms.
Nine of the fourteen human studies focused on spasms; on average, the study participants reported a 2.8 point decrease in spasticity severity on a 10-point numerical rating scale. Of these nine studies, three were determined to be low quality evidence using the GRADE evidence framework. The other six were, however, were deemed to be of moderate certainty.
Other studies examined the effects of medicinal cannabis on pain, urinary incontinence, and sleep-related quality of life outcomes. The quality of these studies varied from moderate to very low, but they generally indicated that medical cannabis formulations could significantly increase patients’ self-reported quality of life. Most notably, across the four pain studies, average pain scores reported by MS patients fell by around 3.4 points (on a 10-point scale) after just four weeks of treatment with the 1:1 THC-CBD formulation.
“To increase confidence in the efficacy of medical marijuana as an add-on therapy in MS, higher-quality, multi-year, randomized, double-blind, placebo-controlled clinical trials are warranted to assess long-term tolerability,” the review authors concluded.
Additional trials could also focus on the presence of any significant drug interactions, they said, as well as the prevention of relapses.
Further studies could explain why cannabis works for MS treatment
The remaining 14 studies looked at animal studies in models of MS. For the most part, these studies sought to identify which mechanisms and receptors in the body may be responsible for promoting cannabis’ therapeutic effects on MS symptoms. A number of human studies also included this as a secondary goal.
These studies provided evidence supporting the idea that the body’s natural endocannabinoids can play an important neuroprotective, regenerative, and immunosuppressive role in MS. For example, in one study it was found that the levels of several endocannabinoids detected in the cerebro-spinal fluid were lower in patients with any form of MS, compared to a control group.
Given the importance of the endocannabinoids to MS, the question arose as to whether cannabis-based medicines might modulate the endocannabinoid system in such a way as to elicit MS symptom relief.
Animal studies looking at receptors known to be activated by cannabinoids, including the CB1 and CB2 endocannabinoid receptors and the G protein-coupled receptor 55 (GPR55), appeared to indicate that cannabinoid therapies can help to reduce inflammation and protect nerves against damage by the immune system.
There was some evidence in the animal studies to indicate that cannabis therapies could also support remyelination. MS is the most common demyelinating disease, where the dysfunctioning immune system begins to attack and damage the myelin sheath which protects neurons in the central nervous system. At present, there is no cure for demyelination.
Based on the results of these studies, the review authors concluded that more exploration of the molecular mechanisms behind cannabis’ effect on MS symptoms is needed. Such studies could help identify the exact signaling pathways which are able to reverse nerve damage and promote the healing of central nervous system tissues, they say.