Medical marijuana and MS: What does the research suggest?

The debate over the legal status of medical marijuana in countries around the world has been front page news lately. Marijuana is well-known as a recreational drug, and its use in the medical world is rapidly growing. Medical marijuana has been used to treat nausea that often accompanies chemotherapy, stimulate appetite, and relieve pain. The use of medical marijuana in Canada was legalized in 2001, and as of December 2013 Health Canada reported that there were nearly 40,000 individuals across the country authorized to possess dried marijuana for medicinal purposes.

Photo Credit: 2010 Mark (eggrole) / Flickr Commons

Photo Credit: 2010 Mark (eggrole) / Flickr Commons

Recent changes to laws on the production and use of medical marijuana has prompted questions from many people who use or are considering using medical marijuana, including people living with MS. Some of the questions we’ve heard at the MS Society are about the research on different forms of medical marijuana, and whether research supports a helpful or harmful effect of marijuana when used to treat MS symptoms.

Medical Marijuana and MS

Marijuana, or cannabis, contains many different compounds called cannabinoids. Two cannabinoids of particular interest are Δ-9 tetrahydrocannabinol (THC), the major psychoactive constituent of cannabis, and cannabidiol (CBD), the major non-psychoactive constituent of cannabis.

Cannabinoids exert their effects by binding to and activating specific molecules called ‘receptors’. Binding of cannabinoids to these receptors in the brain can initiate the psychoactive or therapeutic effects of cannabinoids.

Photo Credit: 2010 Mark (eggrole) / Flickr Commons

Photo Credit: 2010 Mark (eggrole) / Flickr Commons

In Canada, cannabis is administered mainly through inhalation. When people with MS or other conditions smoke cannabis they are taking cannabis in its natural form (it is this form that is now highly regulated by the Canadian Government). Nabiximols, which you may recognize by its brand name Sativex, is a pharmaceutical preparation of cannabis in the form of an oral spray, and is the only cannabis-derivative medication approved for MS in Canada.

There are other preparations of cannabis being tested for their ability to relieve MS symptoms such as pain, fatigue, spasticity, bladder dysfunction and mobility. These preparations, like Sativex, are carefully formulated in labs and have fixed concentrations of THC and CBD. The relative amounts of the cannabinoids dictate the therapeutic effects of each preparation.

  • Cannabis extract: taken orally and can contain both THC and CBD, or CBD alone
  • Dronabinol: man-made cannabinoid that is taken orally and mimic the effects of naturally occurring cannabinoids
  • Nabilone: another man-made cannabinoid

Research on smoked cannabis

A study conducted at the University of California examined the short-term effect of smoked cannabis on spasticity. The study included 37 individuals assigned to smoke cannabis (containing 4% THC) or placebo cigarettes once daily for three days. Findings showed that smoked cannabis reduced pain and treatment-resistant spasticity associated with MS better than the placebo group.

Although smoked cannabis may be helpful in relieving MS symptoms, there are potential side effects that must be considered.

A research team led by Dr. Anthony Feinstein at Sunnybrook Research Institute in Toronto previously demonstrated that smoked cannabis can negatively affect cognition in people with MS, specifically their ability to perform tasks related to information processing speed, working memory, executive functions, and visuospatial perception. In a similar, more recent study funded by the MS Society, Dr. Feinstein and colleagues performed real-time brain imaging of two groups of people with MS, cannabis users and non-users, while each group completed a series of cognitive tasks. The study reported disorderly patterns of brain activity in the cannabis group, which suggests that the brain is likely compensating, or working much harder, to overcome the tasks required.

Approximately 40-60% of people with MS experience some level of cognitive impairment, and so it is very important to determine the potential neuropsychological effects of cannabis use, which may add further difficulty to performing basic tasks and thought processes.

Research on other preparations of cannabis

Clinical trials

CAMS (cannabinoids in multiple sclerosis), a study carried out in the UK, was one of the first large-scale trials to examine cannabinoid treatment for MS. 667 participants were enrolled in the 15 week study. Participants were randomly assigned to receive one of two cannabinoid treatments or a placebo treatment. The cannabinoid treatments assigned participants to receive a capsule containing both THC and CBD, or a capsule containing man-made THC. The study produced mixed results. While cannabinoids appeared to have no effect on spasticity compared to the placebo treatment when experimenters measured spasticity using a clinical scale, the people who took cannabinoids during the trial said they experienced some improvement.

MUSEC (Multiple Sclerosis and Extract of Cannabis) was a 12 week phase III clinical trial carried out in the UK which examined the effect of an oral cannabis extract on relief of muscle stiffness and pain. Participants received an oral capsule containing both THC and CBD, or a placebo capsule containing no drug. Patients who took the cannabis capsule demonstrated significant relief from muscle stiffness compared to the placebo group.

CUPID (Cannabinoid use in progressive inflammatory brain disease) examined the effect of treatment with dronabinol. The trial involved 493 people with progressive MS at centres in the UK. Participants took either dronabinol or placebo for three years. Researchers measured changes in progression using the EDSS and MSIS-29 scales as well as MRI scans to show changes in brain volume. Investigators found no effect of dronabinol on the clinical course of progressive MS or on the rate of brain shrinkage.

Cell and animal studies

One area of research into the medical effects of cannabis which I’m very interested in is the effects of cannabis on the immune system. MS is often characterized as a disease driven by the immune system- so how do cannabinoids play into this?

Cannabinoid receptors are located on immune cells, and so researchers are investigating the therapeutic potential of cannabinoids to act as inflammation suppressants. One study published in the British Journal of Pharmacology demonstrated that cannabidiol treatment led to improvements in mice with MS-like disease. Investigation into this effect revealed cannabidiol suppressed T-cell and microglial activity, two key immune cells implicated in MS.

Another interesting study published in Cell Death and Disease showed that CBD protects oligodendrocyte precursor cells (OPCs-cells residing in the brain which are critical to the remyelination process) during inflammation, suggesting CBD may have therapeutic potential for repair and protection of nerves. However, a clinical trial investigating the potential neuroprotective effect of cannabinoids on the course of progressive MS did not reveal such promising results.

What does this all mean?

Development of treatments for MS is a top priority for the MS Society, and we encourage research into all potential avenues that will lead to safe and effective treatment options.

Photo credit: 2007 Scott Beale / Flickr Creative Commons

Photo credit: 2007 Scott Beale / Flickr Creative Commons

In the case of cannabis, there is still uncertainty about its benefits as a treatment for MS compared to the risks. Researchers emphasize that more work is required to investigate whether cannabis or cannabis-derived therapies can mediate common MS symptoms as well as progression.

As with any treatment, I look forward to seeing further advancement in this area, which will provide clearer answers about cannabis use in MS and assist both people with MS and neurologists in making informed decisions about the most effective and appropriate treatment regimens.

9 thoughts on “Medical marijuana and MS: What does the research suggest?

  1. Jackie Webb

    I have ppms and had problems with my spasms and MS hugs until I started using medical marijuana. It’s not a short term process that you can just start taking it and get better; you have to use it as a tool to teach yourself to relax both mentally and physically for it to do much good, but once you begin to relax a bit, it becomes easier. It’s been about 2 years now, and with 1 year of regular pain injections plus the mmj, I am able to get around better. My MS hugs don’t last as long; I can use my upper arms. I’ve learned that the various kinds of marijuana can help or hinder one’s mind, so one can avoid a lot of the initial intoxication and cognitive fogginess by using Sativa marijuanas, that brighten my skills instead of make me relax too much, like a lot of Indica marijuana does.

    I think a lot more information needs to be out there about the kinds of marijuana; how they can be used specifically to pinpoint certain issues you have. While what it does exactly and how we’re trying to find out more is great, the public at large and institutions have to start accepting it as a valid treatment. My GP, for example, knows that I use it, but she is not able to openly support it because her boss does not openly support it in their clinic. There’s no means for me to talk to the clinic director and tell him what an effect it’s had on me. We just have to hope that it gets to him somehow.

    I am *sure* there are a bunch of people who are just using this stuff to be happy. My point often is: so those of us who suffer intensely on a constant basis because our government doesn’t want some other people to be happy? Is monitoring all of this a drain on an already maxed out health system? The answer lies somewhere in between there.

    I’m a disabled person in a single income home. We are paying through the nose for the meds that I already have to take, and I have to buy this on top of it. If I wanted to take oxycodone or another opiate instead, I would be much richer, much more cognitively fogged, somewhat addicted, and still in pain, because opiates don’t work for my pain, but oh boy, the government supports those. =(

    I know you all understand and share how weighed down one can feel from these things – the whole idea of *having to* take marijuana weighed on me because I totally bought into the “only bad people use this” idea. Having used it, I want to introduce all the good people I know to it so they can stop hurting. Neurologists can work on it too, but in the meantime, it should already be in use as a *tool for healing people’s minds and bodies*, and improving their quality of life, because we *know* it can do that. Quality of life is measurable. =)

  2. Sandra

    My brother has progressive MS. He is now in a wheelchair, has a hand control vehicle. The future does not look bright. Regardless, I’ve been doing my own survey of people I know with MS AND THEIR CHILDHOOD YEARS WERE SPENT LIVING VERY CLOSE TO HYDRO LINES. Not the ones that run up your street but the huge sets of towers that run through our countryside. We grew up where two sets ran in our front yard and the rear yard. We lived in the country on 10 acres. A boy across the street also has MS. As well as 3 other people we know. Is there a study on MS and power lines? Should there be?

    1. drkarenlee Post author

      Thank you for your comment Sandra, and for sharing your brother’s story with us.

      MS researchers are examining all potential environmental triggers of MS. To my knowledge, there are a few European studies taking place which are examining the association between distance to power lines and neurodegenerative diseases, however they are not specific to multiple sclerosis and observe very distinct populations. Thus more research is needed to determine causal relationship between power lines and MS. I will be sure to provide updates on these and other similar studies as they become available.

      Dr. K

    2. Curtis Swedgan

      I lived in the country side in Langley B.C and no where near powerlines and when I was in U.B.C for a treatment I met a gentleman that lived two blocks from me. We figured it could be from well water.. since we were both in the same area for 25 years, and that they think its environmental. were yoyu on well water??

    3. carl

      In just a few years, cannabidiol (CBD) has become immensely popular around the world. After initially being discovered as an effective self-medication for Dravet syndrome in children, CBD is now sold and used to treat a wide range of medical conditions and lifestyle diseases. The cannabinoid CBD, a non-psychoactive isomer of the more infamous tetrahydrocannabinol (THC), is available in a growing number of administration modes, but the most commonly known is CBD oil. There are currently dozens, if not hundreds, of producers and sellers of CBD oils active in the market, and their number is increasing rapidly. Those involved vary from individuals who prepare oils on a small scale for family and (Facebook) friends to compounding pharmacies, pharmaceutical companies, and licensed cannabis producers. Despite the growing availability of CBD, many uncertainties remain about the legality, quality, and safety of this new “miracle cure.” As a result, CBD is under scrutiny on many levels, ranging from national health organizations and agricultural lobbyists to the WHO and FDA. The central question is whether CBD is simply a food supplement, an investigational new medicine, or even a narcotic. This overview paper looks into the known risks and issues related to the composition of CBD products, and makes recommendations for better regulatory control based on accurate labeling and more scientifically supported health claims. The intention of this paper is to create a better understanding of the benefits versus the risks of the current way CBD products are produced, used, and advertised.

  3. Dave Campbell

    Medical marijuana can help in lots of health issues so the legalization of marijuana is right. Benefits of medical marijuana can change the life of people who are suffering from unbearable pains and diseases so we should see the positive side of it too.

  4. Brad Eaton

    Living in Canada I must say that I am thrilled that cannabis will be legal soon. There are so many benefits that have been overlooked for so long,. I’m so glad that it’s finally becoming legal nationwide & hopefully the USA will follow


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