Marijuana’s Long Term Effects On The Brain Finally Revealed!


With a drug war against marijuana still raging in more countries than not, the question of how long-term marijuana use effects the human brain is a pivotal question in its legalization.  Although alcohol remains legal despite heaps of evidence to the dangers of long-term use, the fight to make marijuana available both with regard to its medical properties (especially in selectively killing cancer cells) and non-medical uses has frequently hinged on the various claims made about marijuana’s effects on the recreational user.


Luckily, the debate can finally move out from the realm of opinion into scientific evidence as researchers from the University of Texas just published their research into the long-term effects of marijuana use on the brain in PNAS (Proceedings of the National Academy of Sciences).cannabis-brain

The researcher helped dispel the dying myth that marijuana use lowers IQ, and actually provides more evidence to marijuana’s potential role in fighting Alzheimer’s. The research revealed that earlier onset of regular marijuana use leads to greater structural and functional connectivity in the brain. The most significant increases in connectivity appear as an individual begins using marijuana, with results showing that the severity of use is directly correlated to greater connectivity.

Although these results will need to be confirmed with a larger sample (this was based on roughly 100 participants), the preliminary results do seem promising. More research will need to be done in order to see if these differences are caused by, or simply associated with, long term marijuana use. They also found reduced gray matter in the OFC (orbitofrontalcortex) in long-term users (which is a brain region associated with addiction). It is unclear whether this region is simply smaller in regular users (explaining their regular use) or if the use actually contributed to structural brain changes. These results will also need to be contrasted with other researcher showing that cannabinoids actually promote brain cell growth (neurogensis) even in adults.


Michael Thomas writing for


Get Your Anonymous T-Shirt / Sweatshirt / Hoodie / Tanktop, Smartphone or Tablet Cover or Mug In Our Spreadshirt Shop! Click Here



  1. I want to share my opinion…
    in fact marijuana users can lose some brain power but, just if they use it very often and cobined with a bad environnement… like if you somoke just for smile à bit every day..
    I smoke often, and I think its “good” if you try to devlop you imagination or to share your opinion on something and try to devlop it to à level that after you could not… sorry for something….

    • There are smokers and smokers,
      those who do it to relax, to feel good, while they are working or beeing creative…
      and those who knock themself out…
      and those who just do it, to do it.
      Stupidy will not go away by a sticky…and it will grow by lazyness…I wonder how the results will look on persons, who smoke a sticky and read a book after, will the scan than show a grow and what is the cause of it, the book or the weed…I bet it depends on who is paying the study.

    • 100 is a large enough sample set to gain preliminary data and calculate statistical significance. as long as the subjects were selected at random and the tissue was tested blind then a lot of data can be gained from such a study.

    • Has no effect on the result. if you test 1000 people. The result would still be the same. Cannabis do damage to your brain. IF you like it or not.

    • Sucks to live in Texas, I guess. But srsly, I don’t know how much of it is just stereotype but aren’t the majority of Texas (or at least the Texan gouvernment) strongly conservative and republican?
      I mean, the stereotype we have here in Germany (or at least where I live) about Texans is gunshooting Monstertruck riding drunk guys that go to church and beat their wifes. Ofc thats an exaggerated and probably wrong stereotype but there is always a bit of truth in those…

      • I moved to Texas expecting to see all of that.. in Dallas where im at yo dont see any of that no cowboy hats or any of that shit..

      • I moved to Kentucky, where the stereotype is they may their cousins, have no teeth, and a ton of ppl named bud… My findings were as followed… The first person I met when I moved was named bud, he also was missing quite a few teeth, the first person I went on a date with had his wife leave him for her 2nd cousin…my best friends sister is now married and has a baby with her mother’s ex husband…and yes, dentists in the area I lived in primarily didn’t mess with root canals or any other type of method to save a tooth, they just pull it. So there ya go, it depends on where you live within that state, but it does seem to be truth.

        And since this conversation is in regards to cannabis and scientific facts… I’ve seen PPL ruin their lives who smoked marijuana, but it’s because they were using it incorrectly and their mental health was very unstable. Marijuana IS a downer after the initial high. It’s not good for ppl with depression in my personal OPINION. I smoked in my day, never abusively but I was around PPL who abused it. I know that when I was high, it made me analyze things quite a bit more than normal, but it didn’t make me smarter, the knowledge was there already. I just didn’t use that knowledge. And I suppose after I came down, some of the questions I might have thought of during the high, may have gotten answered. I’m often an over thinker, a worrier, and I’m a very quick learner. None of that started AFTER I smoked weed. Alcohol has also ruined Ppls lives. Some prescription medication approved by the fda had ALSO ruined some Ppls lives. It IS a fact that some things effect some PPL differently than it does others. All of you that are sitting here arguing clearly had your opinion before you read this article. Your gonna have the PPL who believe it’s bad and ppl who believe it’s good for medical reasons and those who just want it recreationally. Scientists can’t tell what it’s gonna do for everyone… It’s just like a prescription drug. They can only study it so far. This whole process is going to take decades to get an idea of who can tolerate it and who can’t. Yes it’s been shown to help certain conditions, but while it’s helping one condition, that same person could have another condition that is not good for. Only time and studies will tell. Then there are always going to be the groups that don’t agree with it being used, but that’s life. Ppl don’t agree on many things in this world. I swear some PPL just need to stop fighting and arguing over this stuff and cutting ppl down for their opinions. We all have our own opinion on these matters. I personally think marijuana is more natural than drinking beer, but I rarely ever smoke that stuff and drink about 10 alcoholic beverages per year. I don’t like drinking and driving and I think being high while driving can definitely cause problems. For instance, you could potentially fall asleep while driving, or, be TOO cautious and cause am accident… But PPL text and drive and talk on their phones and drive, so where is the difference in the danger? Ppl need to be smart about their decisions. That’s all I have to say. Have fun arguing over something that is ridiculous to even bother arguing about. Your working yourselves up over nothing.

  2. This was obviously indorsed by the cigarette company’s. If you didn’t get the sarcasm in the header then I feel like you shouldnt be reading things you don’t understand. Grow up people, especially if you think canabis is bad for you. If so go smoke a cigarette since I bet you think they are better for you

  3. I think that our brain functionality goes better after our first marijuana use. And I think that we should use it once a week. The use marijuana for our brain, body and psychological health it is not necessary but if used, you go one step further in your evolution.

  4. 1. It is very hard, even with just 100 subjects, to recieve clean long term data results.

    2. For everyone it should be clear, that marijuana is a strong natural product, by several studies it has been proofed, that a medicine effect is available, so it is medicine, a miss use of medicine, a drug or anything…let take sugar as an example, have a beside effect, which is mostly a bad effect.

    3. Whoever takes anything over a long time heavily, is a overdose user. There is no need to talk about that, want a logic example…. Everyone who eats 10 times a day sweets or fast food, over the time of 10 years, will become a fatty person, and it is also see able in the brain scans and every teeth doctor can recognize that also.
    Not to mention alcohol abuse, or even the drink of a beer every day for 10 years…that is also abuse, noticeable in the liver.

    So what is the result, the long term results, can be caused by the sweets, smokers tend to eat, by the tabac they use for their stickies, or by the beer they drink to remove the papermouth…

  5. LOL Anon!

    I thought with a headline like this:
    Marijuana’s Long Term Effects On The Brain Finally Revealed!… you would actually give us some useful insight… but with a sample size of 100 people… everybody should be skeptical.

  6. This article is a little biased. I support the use of medical marijuana but this makes it look like weed is 100% safe, which is not, specially for younger users in their 15-20’s. As MANY articles show, it can decrease synaptic efficacy and cause schizophrenia if you’re susceptible. Of course this is with heavy use and from a young age but its important info nonetheless.

    • it’s not the drug that causes the scitsophrenia, it’s the whole rotten system we live in that makes people sick. Cannabis does the exact opposite, and when people are torn to realise the magnitude of things being shit in this world and people around them, they can’t always handle it. And there is not always the right people around to help them. There is abslutely no right for anyone to tell anyone what not to take and eat from the nature. We need to change, everyone of us in a way that we cannot even imagine at this point. Eat acid, love, live, lose your job!

  7. I love pot and smoke it everyday but this article largely misinterpreted the study to which they link. It says something completely different there, though I still find it inconclusive since a 100 people doesn’t provide enough data anyways

  8. I used to get strep throat/tonsilitis 1-2 times a year. Then I started smoking weed and haven’t had issues in 3 1/2 years since, and who knows what else its done for my benefit. Anyone who thinks marijuana is poison or deadly or not good for you is a dirty fucking liar.

  9. *Raises hand*

    I’m living proof with diagnostic assessments before and after cannabis use. My intelligence quotient was 91 visual with all other scores 2 standard deviations below normal. My second showed an increase of all quotient scores with visual at 121 an little to no deviation around 90-100 for all other scores.

    My mentality went from that of around 5-8 years old to young adult. I’m 29. This was over a 4 year period between tests by 2 different independent examiners.

  10. Anyone who is familiar with scientific research can understand that this results are so poor.
    Where is this research published so we can read more of sampling data ?

    There are other facts that the report about this research is very inappropriate such as : name of researcher is not mentioned. Credit part sounds is a proof to show it’s poorly supported scientifically.

    I believe this research is done by a medical student trying to graduate from medical school as a doctor. Nothing serious about it.

  11. Marijuana gave me a panic attack after 2 years of using it. It’s the worst thing that ever happened to me and I used to think that it was a harmless drug by the time, but it’s not.

  12. What they need is a brain scans of before taking and after taking as not every brain looks the same as everyone is different and the scan is of two different people need to see the progrestion as time going by coman sence should tell you all that

  13. I am from the Netherlands, so smoking is not a big issue and a lot of personal experience..
    For some of us smoking tends to trigger psychoactive reactions in the brain and I saw a few friends coming down with serious mental problems. On the other hand it did not affect most of my friends – 8/10 not affected ratio. It can be positive or negative depending on the user. Assuming most commenters did not read the study, it is pointless to debate. Researchers have their ethics and are by all matter no lobbyist, however this article clearly uses the study to make false claims out of convenience. In a free world you should know your enemy better.


Please enter your comment!
Please enter your name here