Do Cannabis and Cannabis-Based Drugs Harm Your Brain?

Do Cannabis and Cannabis-Based Drugs Harm Your Brain?

By Staff.

Long-term use of either cannabis or cannabis-based drugs impairs memory, say researchers who found that mice exposed to the drug long-term had “significant memory impairments” and could not even discriminate between a familiar object and a novel one.

The researchers, from Lancaster and Lisbon Universities, studied the effects of the cannabinoid drug WIN 55,212-2 in mice, and believe their study has implications for people who use cannabis-based drugs to combat chronic pain and other conditions.

More and more people are using the drug long-term due to its legalization in several countries, while more potent varieties are available for recreational users.

Here’s what the researchers found:

  • Long-term exposure impairs learning and memory in the animals
  • Brain imaging studies showed that the drug impairs function in key brain regions involved in learning and memory
  • Long-term exposure to the drug impairs the ability of brain regions involved in learning and memory to communicate with each other, suggesting that this underlies the negative effects of the drug on memory

Dr. Neil Dawson, the lead researcher from Lancaster University said “This work offers valuable new insight into the way in which long-term cannabinoid exposure negatively impacts on the brain. Understanding these mechanisms is central to understanding how long-term cannabinoid exposure increases the risk of developing mental health issues and memory problems.”

He also highlighted the relevance of the work to those using cannabinoid-based therapies to treat medical conditions like chronic pain and others.

“Cannabis-based therapies can be very effective at treating the symptoms of chronic diseases such as epilepsy and multiple sclerosis, and dramatically increase the quality of life for people living with these conditions. We need to understand the side effects that these people may experience so that we can develop new interventions to minimize these side effects”.

Professor Ana Sebastiao, lead researcher at the University of Lisbon, said: “As for all medicines, cannabinoid based therapies have not only beneficial disease-related actions, but also negative side effects. It is for the medical doctor to weight the advantages of the therapy, taking into consideration quality of life and diseases progression, against the potential side effects.”

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Authored by: Staff

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I know from experience cannabis is not free of side effects and there don’t seem to be good studies into the harms of long term use. CBD alone does not work for Chronic Pain (Uni of Glasgow Med School Peer reviewed research 2017). The THC is what works for chronic pain. I have established all I am saying here for myself, via repeat experiences.
1. Cannabis has an horrendous WITHDRAWAL SYNDROME and
2, it makes my skin itch, especially after being in water, a shower, bath, swim etc.
Something g pretty complex we don’t yet understand is going on when CBD and THC is in our bodies. Natural does not mean side effect or harm free and never has. What about digitalis (Foxglove)? It will stop your heart if consumed.


I have only been using MMJ for a couple of years now, and only when absolutely necessary. My memory is better when it isn’t plagued by constant, unrelenting pain from CRPS, Fibromyalgia, and a host of other diseases, as well as PTSD and severe panic and anxiety disorder. Marijuana helps with all of these and I don’t have the side effects of all the other medications from Big Pharma. This “study” is just more anti MMJ propaganda.

One enormous problem with the study is that it uses a synthetic toxin instead of real cannabis. The fact that a synthetic toxin destroys memory means what, exactly, about cannabis itself?

This is junk science at it’s very worst. If I were a taxpayer in Europe I would sue these scientists for defrauding the government.




Even if this is found to be true, I would much rather deal with the side effects of a natural substance over a derived drug whose end results have not been studied on a long term basis, especially given the fact that cbd/thc does NOT create an addiction!!! Kind of have to call BS/Propoganda/Persausion on this given the “It is for the medical doctor to weight the advantages of the therapy, taking into consideration quality of life and diseases progression, against the potential side effects.” quote… doctors are NOT all knowing just because they are Doctors!


I don’t believe this. My memory and cognitive issues began with chronic pain. I didn’t begin Cannabis until 2 years after my injury for pain from Crps.

Howard Techau

Ummm…. Where are the results of this study? You talk about it, but you show no results or how it was done. Not very scientific. Also, the drug used is not a true cannabis drug. WIN 55,212-2 is a chemical described as an aminoalkylindole derivative, which produces effects similar to those of cannabinoids such as tetrahydrocannabinol (THC) but has an entirely different chemical structure.

Cindy Deim

All drugs have some side effect. Long-term use of most any drug probably isn’t good for you. It’s a choice you make when ur in pain. We should all be able to make that choice.


Replace doctors with government! Why not replace researchers with students? This really is getting ridiculous at this point isn’t it? If it weren’t real life it would be funny!


Why talk about pot when there is not a opiate dispensing doctor Who would continue treating someone who tested positive for pot. Now once you can get fired okay now you have to see how long you can exist on something else. Pot, controlled substances. Xcetera. Good luck with that for anyone with severe pain. Can you stay stoned 24/7? I’m sorry, but I honestly think if they want The Chronic pain patient gone! No pain patient, no opiate! Any questions?


I smoked marijuana briefly in college. To this day, I can’t remember that period of time. It’s blank. I am afraid now to try cannabis. Maybe I’m particularly sensitive, but I don’t feel I can try this pain control method.


I remember the saccharine studies that said it causes cancer, but those mice were given equivalent of 1 gallon of it per day for entire study! So, how much of this engineered, apparently much more powerful than than natural cannabis, compound was given and for how long? Yes, cannabinoids can affect your brain but most products are not engineered, just taken from a natural substance. Besides, it really can help lessen the pain, so are some memory problems worth it? Only you can decide!


There IS NO chronic pain cannabis. There is just marijuana. No studies even prove mj relieves pain. Studies do show it relaxes you and you don’t care as much. That is not the same. Some of us want to care.

In my experience, the people I knew 30 years ago were already showing signs that indicate this.


I am not a mouse in spite of my name.I say bs on riduculous study.They are undoubtedly using a huge amount compared to size of thier brains.Also the side effects of many of big pharma drugs have horrendous side effects including death.Thhey are still prescribed.Many opiods cause memory issue.Look at antibiotics ,tedon rupture,capillary leak syndrome.Endless list of terrible side effects from all drugs out there.A little bit of memory seems just about nothing when compared to other medications.I can’t name one drug thats potential side effects that are that innocous.Seriously student studies,really reaching to find fault with cannabis

William Dorn

Opioids have been used safely for thousands of years to treat pain. This fact does not change just because some anti opioid zealots make up false statistics. Cannabis and opioids should be allowed to be used for any medical condition if prescribed by a doctor without government interference.

First mice only live 4-5 max.years. Second how much cannabis were they exposed to? Were they exposed 24hr.per day ? You can not compare these cheesy studies done by students as they believe is true. I for one don’t trust any studies students do period. They are not professionals and certainly not scientists. I call [edit]. College students get real. Redicoulous to think it’s factual. I’ve smoked off and on since my twenties (I’m 61) and my memory is fine until recently illness & pain starting causing my ability to remember small things but,i think most of it was caused by extreme chronic pain. Flares ups are times when I’ve had trouble remembering little things. I had an exceptional memory my entire life. So I absolutely don’t believe a word of these students school project because they are indeed projects to get required credits in college.


Yes, more negative data like this must be taken into account. There is no medication or herb or plant based modality used for chronic pain that doesn’t have negative side effects. I personally believe for some chronic pain cannibis be it smoked or taken in the form of CBD has been proven to really reduce chronic pain. People may say their pain is the worst it ever has been yet say if they smoke it or use CBD then say it helps tremendously. It is a psychoactive drug that may give the person a feeling of well being. It should not be marketed as a replacement for opioids, only an alternative modality. Studies have proven smoking marijuana in developing minds does adversely affect the brain.