Cannabis: An MS researcher's perspective

I have been interested in the effects and side effects of smoked cannabis for many years. Having been involved in multiple sclerosis research and patient care, I’ve had a significant minority of my patients report smoking cannabis on a regular basis – indicating that it helps with pain, spasticity or both.

In a disease without a cure, such as MS, good symptom management is important and if indeed smoked cannabis is proving helpful, then these potential benefits need to be weighed against the possible side effects of further cognitive dysfunction.

Forty to sixty percent of people with MS will have cognitive difficulties. These problems relate to working memory, speed of information processing and problem-solving abilities. To date my research group in Toronto has published two papers showing that people with MS who smoke cannabis are likely to experience even greater cognitive challenges. This suggests that cannabis may, and I stress may, have cognitive dysfunction as an important side effect. The most recent of my two published papers was a very careful comparison of cognitive abilities in a group of 25 people with MS who smoked cannabis and a demographically and a disease-matched group of 25 people with MS who did not. The rates of cognitive impairment in the MS cannabis group were twice what they were in the non-cannabis smoking group – particularly related to a further delay in speed of information processing and greater difficulties with problem-solving or executive function.

I have used the word “may” above because to date our sample sizes have been modest. We are currently embarked on a third cannabis study where the cognitive results appear thus far to replicate the earlier ones. We have incorporated functional MRI in this new study to see how the brains of cannabis smokers differ from those of people with MS who do not smoke when it comes to solving a particular cognitive problem. The data for this aspect of the study has not yet been completely analyzed. 

I believe that it is important for researchers to look carefully at the side effects and potential benefits of cannabis. To date, we have no clear figures on how many people with MS may smoke or ingest cannabis. Within the broader Canadian general population we know that 15-20 percent will have used cannabis at some point in their lives. Recent data from the general population show quite convincingly that should a person start using cannabis as a teenager and continue use on a regular basis into mid-life then cognitive problems are likely to arise. We do not yet have that same degree of certainty with respect to people with MS.

There are many uncertainties with respect to cannabis and only good research will be able to clarify them. Given that three separate studies from my lab have arrived at the same conclusions, the advice that I give my patients is as follows: should you be contemplating using cannabis because you believe it will help your pain or spasticity or both, do so with an understanding that it might cause cognitive problems or further aggravate existing cognitive problems. Like many situations in medicine the physician and the patient must weigh up the benefits and risks of any intervention. Should one side of the equation outweigh the other, then the clinical course becomes clearer. In time, as more data come in from my lab and those of my colleagues, the uncertainties that currently exist will almost surely give way to a clearer set of do’s and don’ts when it comes to cannabis treatment guidelines.
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Anthony Feinstein, PhD

Anthony Feinstein, MPhil, PhD, MRCPsych, FRCPC, is a behavioral scientist, professor of Psychiatry at the University of Toronto and Chair of the Medical Advisory Committee of the MS Society of Canada.

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  • Terri   Jun 11, 2013 9:35 AM
    I tried cannabis about 5 years ago for MS. All it did was give me a "high", giggle, and fall down. I am not saying it won't work for anyone, I am just saying it didn't work for me. I can fall down and giggle just fine without it.
  • James   Jun 11, 2013 9:40 AM
    I don't smoke on a regular basis, nor am I a huge advocate that blindly believes in the healing power of MJ. With that being said, I have smoked marijuana as a way to control my pain level when I was off my medications. It worked for me. I'm not sure if it was because I was high enough to forget the pain in my limbs, but it sure did let me sleep. I think we need to treat marijuana use for people with MS the way we treat the drug: different on a case-to-case basis.
  • Deanna Kier   Jun 11, 2013 9:59 AM
    I smoke when the pain gets unbearable and yes it helps. Pain pills makes me sick and I wouldn't want to be addicted to them anyways. Canibus is not addicting''''''
  • Deborah   Jun 11, 2013 10:07 AM
    My cognitive dysfunction is much worse with Gabapentin and all of my prescribed meds, than it has EVER been, while smoking fact, it's the complete opposite, for me. MJ increases my mental capacity, alleviates the pressure behind my eyeb alls, holds down my neuropathy to a dull roar, when it's usually so awful, it makes me weep...and gives me some appetite, because with all of the meds I take, I've los tover 30 ponds in the last year. Smoking a bowl also ensures that I get enough fluids in my system, because of it's "Cotton-Mouth" properties. Having been aised among the Lakota Sioux (Rosebud Rez, in South Dakota) and subsequently moved deepinto New Mexico with the Navajo and Spanish cultures, it's tthe same, as far as the healers are concerned: it is a medicine, not a party drug. The Shaman all know it, curanderas know it, and many current doctors os western medicine, know it, it helps me tremendously, and as a side effect, makes me happy and hopeful. Check the side effects of all of my pharmaceutical prescribed meds. For me, it's a no-brainer....and it's natural....from our Creator. So.....this is my most humble opinion. Happy Tuesday!

    chamomile, it is a known medicine in nearly every


    laves, ch amomile, or one of the countless herbs, put here like all of the others, and has many good medicinal usages
  • Catherine Faire   Jun 11, 2013 10:08 AM
    Pot has so many bad side effects. I don't understand why people ignore the harm it can do. I have a family member in a home from pot. He is clueless as to what day/year/location it is. I don't take pain killers. Magnetic bracelets helped my hands. I'd rather be in pain than walk around in a diaper because I couldn't remember to go to the bathroom or where it was like my brother in law. He isn't the only one either. I have a couple of others messed up. Smoking pot is full of carcinogens and a known allergen. To see a Dr push for smoking it is disturbing to me.
  • Holly wickizer   Jun 11, 2013 10:14 AM
    I am an individual with ms that currently had no cognitive symptoms or lesions I'm that area of my brain. I have been looking into how this would b an option for pain relief from other ms issues like nerve cabbage pain and severe spasticity. I'm very interested in your study and if to are looking for patients that I would fit into one of your studies I would greatly appreciate if you would consider me or could send me singe more information about your studies. I look forward to hopefully bring asked to become involved or at least learning more information about this. Thank you.
  • Linda Guest   Jun 11, 2013 10:15 AM
    After reading your findings re smoking cannabis i have to say that as a ms sufferer who does have spasms be it mainly towards evening time and throughout the night. My sleeping pattern was a nightmare. A friend introduced me to cannabis so i decided to give it a go. After two nights, smoking it only at night my spasms were vastly reduced and my back pain was bearable where as before cannabis the pain was intolerable. I only smoke one joint per day and now im alot more settled and mainly pain free.
    The spasms are now minor by comparison. You dont need to smoke it as it can be combined within food too.
  • Ann   Jun 11, 2013 10:42 AM
    For my mother who was in the final stages of progressive MS it was a miracle. She could not eat or sleep. Because I feared she would have trouble smoking it I added it to a cookie recipe. One cookie per day gave her relief from pain, made her hungry and allowed her to sleep a full 8 hours. I am glad I could do something to help her be comfortable during her final days.
  • Denise Johnson   Jun 11, 2013 10:45 AM
    When smoking or ingesting MMJ, it is important to use the proper strain. MMJ has two very different type of effects of folks, depending on the strain. If you are having muscle spasms or pain, or feeling anxious, or having difficulty with sleeping go with a Indica strain. If you need something to get you up and going (from fatigue) then you want a Sativa strain. I you smoked sativa for pain you will not have much or any help from it. The type of stain matters. MMJ has helped me than any other drug I have received from a doctor. I can use a indicia to help me sleep, I have absolutely no side effect the next morning like I would have from a sleeping pill. I do editables which is the best way to take it. It also last four times longer than smoking. I am happy to live in a state that embraces MMJ. I am able to grow my own, It has been a blessing for me.
  • shannon custer   Jun 11, 2013 11:13 AM
    why cant we ask Montel Williams ? He is an advocate for smoking and the helpful benefits of it.
  • Wanda Wood   Jun 11, 2013 11:56 AM
    What are the side effects of the THC pill. Are they the same? Don't think I want to smoke it. Does the pill make you high?
  • Ronnie   Jun 11, 2013 11:57 AM
    I have m.s. desperately looking for a compassionate doctor in NJ for a referral too Greenleaf Compassion center any help is greatly appreciated:-)
  • Wendy   Jun 11, 2013 12:23 PM
    You do not have enough information to make any assumption on the benefits or lack of benefits. You need more research! My sister suffers and is a PO, she would not consider smoking because of the legalization but some days I feel sad that she suffers.
  • Christine   Jun 11, 2013 1:32 PM
    There are stains that are high in CBDs and low in THC. CBD is the part that helps with pain and spasticity without making you very "high". I am lucky to live in a state where it is legal and where my doctor monitors their patients. I do not use it often but when things get bad it's a life saver.
  • AnonyMS   Jun 11, 2013 1:48 PM
    @Catherine Faire
    Come on now. No one is "in a home from pot". Either you are lying or you were lied to. The brother in law was taking something else if he is in a diaper.
    I have smoked 15+ years nearly every day and I can find the bathroom just fine.
    While it does affect everyone differently (just like MS itself), I have never heard or seen a study of a person disabled like this from cannabis.

    The worst side effect I have witnessed with my own eyes over many many years was one person got very paranoid for a short while.

    Also, you DO NOT have to SMOKE cannabis to ingest it. There are many SMOKELESS options.
  • AnonyMS   Jun 11, 2013 2:02 PM
    Dr. Feinstein,
    Did your study include various strains and types of cannabis?
    Indica's and Sativa's each have their own affect on cognitive function with their varying levels of TCH/CBD.

    Some important variables are being dismissed or forgotten. Too much to have three different trials and to call the results conclusive...

    I would bet you receive slightly different results with the same study comparing THC to CBD strains.
    I have to dismiss cannabis cognitive research that do not disclose this kind of information as it is incomplete.
  • Carla Ricca   Jun 11, 2013 2:13 PM
    I have MS & have smoked & consumed Cannabis daily for the past 2 years & am no longer on ANY prescription medications. I do not have any cognitive issues, if anything I function much better. I have not had ANY negative side-effects, but instead have discovered much relief from muscle spasms, nerve pain & overall have been able to live a productive life without taking 20 pills.

    For those who are afraid of trying it but are desperately seeking relief, cannabis can be taken in many forms & smoking isn't required, and I promise you won't regret it. Just remember that pharmaceutical drugs are a 1000 times worse for you than cannabis!
  • shirley ann tobin-wilson   Jun 11, 2013 2:14 PM
    has any testing been done on hemaphiliac? my son is 32 .he has no factor 8 at all. he's been through the pill stage and he doesn't want too go back, but what choice does he have

  • Christina M   Jun 11, 2013 2:16 PM
    Smoking/ingesting Cannabis may NOT be for Every MS Sufferer. Just as Baclofen or Valium may not be for every MS Sufferer. That's why experts say to discuss it with your doctor BEFORE you start self-medicating. Side effects come with just about EVERY prescription, so why would anyone think cannabis would be any different. That being said - Anti-depressants affect the cognitive responses of people until their bodies build up a tolerance to it, most pain killers do the same. Just about any drug that is classified as a CNS Depressant affects a persons cognitive responses, with that in mind, I can't see any GOOD doctor advising a person to combine cannabis with other like medicines UNLESS symptoms are soo severe that it's the only way a person will gain any kind of relief.. Lastly, nowhere in this article or Any other article that I've read on this topic does it say that the subjects of this kind of research were HIGH! It does not indicate how much these patients smoked/ingested. You CAN ingest cannabis WITHOUT getting high! There's my two-cents worth! :-)
  • Amanda   Jun 11, 2013 4:12 PM
    I was dx in 04 and I was depressed all the time until I started smoking cannabis. Pills, antidepressants make me sleep Way to much, and was not able to care for my children. Now I'm awake and cooking dinner.It's been a Great Help.
  • Tim Hendricks   Jun 11, 2013 8:17 PM
    I used marijuana back in the 70's and 80's but quit i 1988 when my son was born. i van't used since then. The medications I have used for my tremors don't seem to work very well. I will not take any pain medication that is opium based or the ones you can get addicted too. Over the counter pain medicine do little for me but that's what I am using now. If I did start using cannabis again I would use it only in small amounts. My problem is my state does not allow medical marijuana. I believe if a person doesn't abuse it they shouldn't have any problems or side effects.
  • Geoff boon   Jun 12, 2013 7:34 AM
    Hi Doc i 2 have ms and i find that theres alot more relefie from hurb than any pill unless u want 2 become a zombie life is hard enugh without paying so much 4 it :(
  • Sue   Jun 12, 2013 9:34 AM
    After observing the result of long term pain management with opiate based meds, muscle relaxers etc. I would much prefer to see my spouse smoke marijuana than to be stupored and fall asleep while I am talking to him or his losing his memory from pain pills....sort of a deceiving study. There are pluses and minuses to all treatment options. I don't think any level of pain and/or pain management narcotic options all cause some congitive difficulty. It is a trade off.
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    nichke  Jun 19, 2013 6:12 PM
    Thank you for addressing this. After battling ten years with pain management I chose to try marijuana. Luckily, it is legal for medical use here in California. What I've found is that it does help overall with my pain but is not a magic bullet. It allows me to relax which lessens the muscular-skeletal pain. However, my short term memory while I'm using marijuana is basically nonexistent. So for me, yes it provides pain relief and most certainly alters cognition. Just thought I'd share.
  • jose Allen   Jun 21, 2013 4:26 AM
    Are there any studies that explore a possible connexion between the use of cannabis in youth or by parents and the later developement of M.S.?
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    billyballgame  Jun 22, 2013 1:58 AM
    I use cannibus nightly as a sleep aid, and it works wonders. I rarely have issues with pain. I do worry about cognitive issues, though.
  • Theresa13  Jun 26, 2013 12:54 PM
    I so believe in Cannabis. I wish MD would approve it
  • Lynn McClatchey   Jul 7, 2013 10:43 AM
    As a nurse working with patients in pain,some with MS, I thank you for your balanced reporting on a treatment given much media attention. I agree that cannabis treatment guidelines are WHAT PEOPLE NEED to understand this alternative therapy. People in chronic pain and families who are standing by watching often lose perspective when choosing treatments. Honest, reliable information to promote informed choices is so important. Thank you.
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    crazygoin66  Jul 8, 2013 4:55 PM
    I am allergic to pain meds. ugh I would have no way of managing my pain with out it! Georgia needs to get with the program. lol
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    sarasmile4  Jul 16, 2013 10:39 PM
    I have noticed a difference in mental clarity when you use a vaporizer or make an edible as compared to burning paper and butane. Or is that just wishful thinking?
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    monicadynak  Jul 17, 2013 11:53 AM
    Sara I have noticed the same thing. Smoking it just like normal does not have the same effect for me as eating/vaporizing. I have also noticed Hash is more of a 'pain killer' for me
  • Zak A H   Dec 14, 2015 4:48 PM
    I am an MS patient of 11 years and I have just started the treatment to control my MS from progressing and to relieve some of the symptoms (I struggle to walk and need support to keep balance). It has been several weeks since I started however I have not yet felt or seen any improvement in my health. In fact, I feel as though my health has gotten worse. Is this to be expected before I see any sign of improvement? I understand that my body is getting used to the new chemicals and may need some time to repair before I start to feel better, but I'm not as optimistic and confident of this treatment as I was before. Therefore, I am interested in knowing about your experience especially how it affected you at first, and when you began to see improvement in your health. MS is a daily battle and I'm eager to meet more patients like me, who may be in some way be able to help me with advice through their personal experience. I look forward to your replies or comments.
    With thanks,