Marijuana & MS: An interview with Dr. Robert Fox

This month, we sat down with Dr. John DeLuca and Dr. Robert Fox to discuss your questions about marijuana and MS, as part of our new Discussion of the Month feature. Read our interview with Dr. Fox of the Cleveland Clinic below. Our interview on marijuana and cognition with Dr. DeLuca can be found here.

Would you please briefly explain the research that you have conducted related to cannabis use for MS?

I am the managing director of the North American Research Committee on Multiple Sclerosis (NARCOMS). NARCOMS is a voluntary registry for research, treatment, and MS education that actively follows over 14,000 people living with MS. The main component of NARCOMS is a semiannual survey asking participants about their lives with MS, with occasional additional surveys. All NARCOMS surveys are confidential and some are anonymous. In one such recent survey we asked participants about their views and habits of marijuana use (including medical marijuana and medications derived from marijuana).

More than 5,600 of our NARCOMS participants responded to this special survey, conducted over the course of a month [August 2014]. Results indicated that 63% of respondents had tried marijuana at some point prior to their MS diagnosis, and 53% have thought about using it for MS. However, only 26% reported having used marijuana for their MS. And, less than half of those who have thought about using it for MS have spoken to their physician about it. Full results of this survey will be released in early 2015.

Do you have any advice for people who are considering using marijuana to manage their MS symptoms and not sure how to approach this topic with their doctors?

It isn’t uncommon for people to be reluctant to talk about private or personal issues regarding their healthcare. Topics that one generally keeps private — such as bladder, bowel or sexual difficulties — can be somewhat awkward to talk about with a physician. And I think marijuana can bring up similar feelings for some people. In many states marijuana is still illegal, and indeed under federal law marijuana is illegal, even though some state laws have legalized it in different fashions. I think altogether that does create a stigma around marijuana that can often make patients hesitant to bring it up with their physician. This reluctance can be overcome if the patient is just honest with his or her doctor about their interest in and perhaps concerns about the use of cannabis as a potential treatment for MS symptoms.

Is there any advice or cautions that you offer to people who may want to consider cannabis to treat symptoms of MS?

I think people who may consider cannabis for their MS symptoms should first talk to their physician about it. It’s important that their physician is aware of their interest, and can give them specific advice regarding the potential impact of cannabis on their health. That said, recently there has been some work to better understand the potential role of cannabis in treating MS. 

In April of this year, a panel of The American Academy of Neurology reviewed complementary and alternative medical treatments in MS. They found that oral cannabinoid therapies (either as pills or sprays) are effective in lessening patient-reported MS symptoms of spasticity (muscle stiffness from MS) and pain related to spasticity in MS. So there does appear to be good evidence supporting a benefit of cannabis on spasticity and pain from spasticity. On the other hand, there clearly can be cognitive effects of cannabis on people with MS. So, people need to recognize that while there may be some benefits of this line of treatment on some MS symptoms, it could impact cognition or thinking.

Of course, it is also important to recognize the local legality of cannabis whenever clinicians make recommendations to patients.

So, you mentioned pain and pain from spasticity – has it been studied in relation to other symptoms?

Yes, researchers looked at cannabis with tremor, and it was found not to be helpful. It has also been studied in slowing down MS disease progression, but that study was negative. So right now, we don’t have evidence to suggest that it slows down progressive MS. The only clear evidence we have to support a benefit in MS right now is patient-reported benefit on spasticity and pain from spasticity.

If someone were to consider using cannabis, should he or she still continue their other treatments?

Where appropriate, cannabis should only be considered a potential treatment for symptoms of MS. It should not be considered as a replacement treatment for disease modifying therapies of MS. We don’t have evidence that cannabis alters the underlying course of the disease. It should not be used instead of a disease modifying therapy that has been recommended by a patient’s physician.

Do we know anything about how cannabis may interact with other medications that people are taking?

There are a lot of things we don’t know about cannabis, which includes the long-term complications of cannabis with a particular focus on cognition, as well as its potential interactions with other medications that MS patients may be taking.

Is there an ideal dosage of marijuana that someone might take?

One of the challenges of smoked cannabis is regulating and standardizing the dose of cannabinoid that is delivered to a patient who takes it — and it is very hard to standardize that and to keep it consistent over a period of time, because of variation in the preparation of cannabis. The oral cannabinoid preparations have helped by standardizing the dose, but translating that to smoked marijuana is very difficult.

While we are on the topic of smoking, a lot of people are really concerned about the negative effects of smoking. Have there been any studies or information about the efficacy of other delivery systems?

Outside of the US there are some pharmacologic preparations of cannabinoids that do not involve smoking. I think it is reasonable to presume that they would be safer mechanisms of delivering cannabinoid therapies, since they don’t have the side effects of smoking. Smoking cannabis has the same potential risk as smoking tobacco. In fact, typical cannabis users will inhale more deeply and will hold the potential carcinogens (cancer-causing chemicals) in the lungs longer, which may further increase the safety risk with smoked cannabis.

How can people get involved in NARCOMS?

NARCOMS is open to any person with MS who is interested in participating in MS research. Visit for information. By participating in NARCOMS, patients can help contribute to research on their disease, all from the comfort of their own living room, kitchen, or wherever they happen to be. By completing surveys just twice a year — and occasional additional surveys — people with MS can help improve our overall understanding of MS. There are many ways that people can get involved in research, and this is perhaps one of the simplest.

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