Cannabis & Cognition: An interview with Dr. John DeLuca

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 about marijuana and cognition with Dr. DeLuca, Senior Vice President of Research & Training at Kessler Foundation, below. And check back tomorrow as we talk with Dr. Fox about how to talk to your doctor about marijuana, whether or not to continue on your other medications, what we know about various forms of cannabis and cannabinoids, and more.

Dr. DeLuca, would you please explain the difference between cannabis and cannabinoids?

Cannabis is the name of the plant that people refer to when they talk about marijuana. Marijuana is more of the lay term, usually associated with the psychoactive form of cannabis. Cannabinoids are the chemical components contained within cannabis the plant. There are approximately 85 cannabinoids in cannabis. The one that people typically think about is THC which is the psychoactive cannabinoid within cannabis.

Cannabinoids activate specific receptors throughout the body, particularly in the nervous system and the immune system, which is where THC would have its psychoactive effect. However, there presumably are other effects that are physiological in nature, because of how they react with the receptors. There is some evidence suggesting that these cannabinoids affect pain sensation, mood, appetite, memory and concentration.

What do we know about some of the short-term cognitive effects of cannabis use?

There are acute effects of cannabis use that have been fairly well recognized in the scientific community. These include decreased reaction time as well as effects on concentration, processing speed and memory performance. It can also have a potential impact on driving. At particularly large doses, cannabis can cause anxiety, depression, even hallucinations and delusions, in addition to more severe cognitive problems. However, it’s important to understand that there are no simple answers for every single individual – it depends on a number of factors.

And what about research on cannabis and cognition specifically related to people with MS?

There have been a few studies on persons with MS – one of which was recently published in 2014. The majority of study results have been consistent in that they suggest an impact on cognitive impairment. These studies involved chronic users compared to non-users, which means that they don’t tell us much about people who use cannabis on occasion. The primary effects seem to be decreasing processing speed.

Other studies show decreases in working memory executive functioning, visual-spatial perception, and memory. And one study even found a twofold increase in global cognitive dysfunction. So, the research studies to-date pretty consistently show that there are cognitive problems associated with chronic cannabis use. Now, this is important, because this is in a population that is already at risk of cognitive problems. It is really important for people with MS to understand this and consider this when thinking about using it to treat MS symptoms.

Is there anything else you would recommend people who are considering using cannabis to treat some of their MS symptoms to consider?

When you have a disease such as MS that affects the brain, it’s important to consider that THC can have negative consequences on cognition that might be detrimental – specifically on areas of the brain such as the hippocampus (which would involve memory), amygdala (which would involve emotional learning and emotional processing), and prefrontal cortex (which can affect working memory).

On the other hand, some research suggests that cannabis can help with things like pain, or bladder function. I think that the discussion needs to be a weighing of risks and benefits of both cannabis and other treatments that can be utilized to treat the same symptoms. I think that we need more research to find out whether it’s really the THC cannabinoid that is beneficial, or some other cannabinoids within the use of cannabis that might be better for treatment of specific symptoms.

The other important point to consider is if you just get cannabis from the street, you don’t know what’s in it. You don’t know dosage. You don’t know if there is anything other than the cannabinoids which are involved. So, oftentimes people think of marijuana as just marijuana but it varies a lot, and it varies by intensity, dosage, and it varies by cannabinoids that are within it. It’s easy to presume that because cannabis is a plant and it is found in nature, it is not going to have negative effects on you, but more research needs to be done to understand the benefits and side effects. 

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  • lkcjody  Oct 30, 2014 3:47 PM
    How effective is the synthetic version?
  • Tom Biel   Oct 30, 2014 3:47 PM
    What about PAHs in smoke from Marijuana? That's Poly-aromatic-hydrocarbons carcinogens found in cigarette smoke. Also possible trace metals and pesticides. These could be unintended consequences to medical marijuana.
    Thank you,
  • ben   Oct 30, 2014 4:08 PM
    When I was first diagnosed with ms it was right out of high school... the Dr think I have had it for a while. The only time I ever had any kind of symptoms is when I quit smoking marijuana to get a job. After a couple weeks of non smoking my legs and arms went numb. I was helping my symptoms while in high school while smoking.
  • Birtha   Oct 30, 2014 4:57 PM
    Marijuana does help with MS and alot of other sicknesses. No smoke comes from marijuana. It is your choice which way you want to consume it. It is a plant / a herb. Whatever you puchase puchase it from someone you trust. I don't know what food manufacturer do with the food but I trust them enought to buy their product. It is the same transaction with marijuana. We (people with MS) must be our on advocate!

    These dortors are only giving open ended information. Nothing they are stating is solid or concrete. They are, probably, working for some big pharmaceutical company. Help stop the suffering, please!
  • John   Oct 30, 2014 6:10 PM
    Dont ask a doctor. Ask the patient who is on the medication. They will know if it works.
  • John   Oct 30, 2014 6:10 PM
    Dont ask a doctor. Ask the patient who is on the medication. They will know if it works.
  • Mr Obee   Oct 30, 2014 6:16 PM
  • Sharon Bush   Oct 30, 2014 6:35 PM
    I choose to smoke marihuana after working full time instead of alcohol. It helps me relax before bedtime. Also, I was constantly having MS bear hugs ( not hardly--more like boa constrictor) and a friend brought me a special brownie and now my "hugs" have been gone for over a year. There was not one RX that achieved this result. Thank God for good friends.
  • Melody Houseworth   Oct 30, 2014 7:49 PM
    I have MS and I hate taking pills, & I have pain all the time, plus my memory is really bad too. I have talked about this with my Doctor & he said it could help. Please let me know if this will help me in any way Please & Thank you & God Bless
  • gloria corbitt   Oct 30, 2014 8:30 PM
    If people can get pain medication and od on it y cant they have marijuana and it only makes you so high for one thing and it really helps the people that really needs it...
  • Catherine Bailey   Oct 30, 2014 8:41 PM
    does cannabis have eny effects on vision? or cancer?
    I have MS and breast cancer. seems that the Copaxone and Methotrexate triggered the CA twice before they agreed that it was triggering the cancer. Have been very rempted to try to find a reliable source to try this drug. Thanks for telling some specifics. Helps confirm my reluctance.
  • Catheeine Bailey   Oct 30, 2014 8:42 PM
    What about the effects of the synthetic version?
  • marsha   Oct 30, 2014 8:46 PM
    I have been a daily smoker for 48 years. My memory is perfect. I had my first attack of optic neuritis at 20. After twenty years, I was finally diagnosed at 40, by a Belgium neurologist. He asked how fast the attacks occurred. Slowly, I responded. What helps you? Smoking pot! I was fortunate not to have engaged in an uptight neurologist. Realizing that some strains actually make you feel symptoms more, I tend to stay with Sativa. It gives me lot's of energy. We all get this miserable disease differently. I would never use edibles as one has no idea of dosage. So if you want to try it, take a few sips off a pipe or joint and see how you feel. I am now in a progressive state but my life is filled with activity.
  • pam turner   Oct 30, 2014 10:46 PM
    Thank you for this has been an insight for me to understand why it may not be suitable for other medical problems..i have signed petitions for its use for people who are facing death, or people who face a future of chronic pain .
  • sandra   Oct 31, 2014 3:11 AM
    lets find a cure/////// keep movin!
  • Chris   Oct 31, 2014 8:04 AM
    I think a more important study would be the efficacy of cannabis in relation to the side effects as compared to pharmaceutical pain killers and disease modifying medications. The list of negative, debilitating, and potentially deadly side effects of pharmaceuticals compared to some possible memory loss and slowing of cognitive function with cannabis seems like a no-brainer to me.
  • S. Kemp   Oct 31, 2014 9:37 AM
    Cannabis user for sever years to control spasms and pain. Use vaporizer to minimize lung damage. I fret when leaving town because it helps me so much. Use minimal amount, no "high" feeling at all. My ability to walk is improved for a bit, clarity of thinking based on my LUMOSITY scores, no pain , no spasms.
    How can you argue with that?
  • Bobbie Cayce   Oct 31, 2014 10:45 AM
    I've been reading about marijuana and MS. My 43 yr old son was diagnosed 2 years ago, possibly as a result of GWS. My question is this, is alcohol less or more dangerous than marijuana ? He likes a couple Jameson at night.
    He is/has been a hard working and busy man but is now on short term disability. I worry about depression especially with the combo of drinking. Wouldn't marijuna be much less harmful.
  • LAURIE GARVIN   Oct 31, 2014 2:44 PM
    Not comfortable using cannibals My memory is not that bad..
  • Jim   Oct 31, 2014 4:53 PM
    There was no mention of the Cannabis that has a higher concentration of CBD as opposed to THC. I understand that it is the CBD that has the great medicinal benefits.
  • marie Dicken   Nov 2, 2014 11:52 AM
    i have never used cannabis but will try anything for the pain
  • Lynda   Nov 3, 2014 1:55 AM
    Much more research needs to be done. As a controller of severe pain, it works well and in improving bladder function. Used as a tincture or taken as a capsule, should not give the same side effects as smoking it will. Cognition issues in taking the cannabis in this form I can't comment on at this stage
  • stephanie   Nov 3, 2014 7:28 PM
    Could you tell me,as a patient who gas relapsing unremitting Ms..and also a long time sufferer with RSD...who is currently on Copaxone shots and 4800mg of Garbapentin ...who cannabis be an outlet to me as more of a "Nerve pain " sufferer???
  • Avatar
    Anne-Clare  Nov 4, 2014 7:30 PM
    It is strange I know but I have ADHD and cannibas has the opposite effect on me. It increases my concentration, energy, focus, and helps with MS spasms. The problems I find with using cannibas is it interrupts my sleep, causes extreme vivid dreaming, and I develop a headache. So, for me, it has the usual positive, and negative effects.
  • Avatar
    Anne-Clare  Nov 4, 2014 7:30 PM
    It is strange I know but I have ADHD and cannibas has the opposite effect on me. It increases my concentration, energy, focus, and helps with MS spasms. The problems I find with using cannibas is it interrupts my sleep, causes extreme vivid dreaming, and I develop a headache. So, for me, it has the usual positive, and negative effects.
  • Natalie   Nov 5, 2014 6:12 PM
    Really now. It certainly can't be any worse for us than any of the other Poisons that are prescribed to use for pain, muscle spasms and those that supposedly slow the progress of the disease. The potential side effects of such drugs and those actually experienced by those of us 'using' the poisons are just as bad and in some cases Worse than what smoking a joint or popping a cannabis pill might do to us.

    Legalize cannabis. Make it readily available and easy to buy. It's our bodies and our choice.
  • classic58woman  Nov 19, 2014 11:41 AM
    I'm interested in medical, pills don't work, constant progression, pain, walking getting worse daily use cane and rollater, Drs in denial, they don't know enough👺 I do I cross referenced and live this daily. My diagnosis: non specified multiple sclerosis, adverse onset, cerebral degenerations, dementia early onset Alzheimer's 😡 pills, pills,bpills👊 no medical help, no therapies, no assistance 😓 I am my own caregiver been homebound since June 2012😧 I'm not afraid ✨ I know genetics, environment, BACTERIA, viruses, processed foods and chemicals play a large role in these diseases
  • Fudge   Jan 10, 2015 10:47 PM
    aryt, good to see that Some research has been done one MS and dope. I have been a "chronic" alcohol and weed fiend since i was 14 and 17 respectively, found out i had MS about 6 month ago. Of course, if anything, the news has made me drink and smoke more, it helps numb the pain of the needles, so long as i time them so im not too inebriated to deliver the injection. My memory was never good anyway and processing cognitively always had a delay, since i was a lad. I'm a drummer, i never thought MS would even be anywhere near consideration for all the diseases i could have, but even intoxicating myself as much as i have, taking the odd crazy like coke or MDMA, DMT or mushrooms, ive so far learnt that a nyt off the copaxone doesnt do any harm so long as you make sure you get the next day, the lumps can be a *****! for me its that the needles have never really got any easier, medicating the way i have been has been helpful but ive had no real advice from the doctors as they just dont know about an individuals chemical health or of any interactions any of these drugs could have. As to MS, apart from the optic neuritis, ive never noticed it impede much of my live, the occasional weakening of some muscles or some sleepless nyts but im still drumming fine, a process that requires mind and body cooperation. beiing a musician i find myself inebriated more often than not, but i have to take care of myself and try to remain responsible over how i go about messing with drugs, ii do my research and never go off the deep end, not had any problems so far. i could do with doctors being able to understand my perspective of living with MS and in general more, i would happily offer myself to be a guinea pig. these days research and funding into medicine and health is sparse, i would like to see more doctors like House! I suppose the only advice i could ever give is to just hack it, it hurts, its not nice, but find your own way of dealing with it, soon there will be a solution. I always have a good meal, meditate/relax for a bit, listening to good happy chill music throughout, remember to breathe properly, day at a time i can deal with this, i wish that anybody dealing with this also can find their way to live a fun happy life too, together we will all beat this, hold tight, peace