Does Marijuana Cause Permanent Brain Damage in Adults?
Does Marijuana Cause Permanent Brain Damage in Adults?

63 thoughts on “Does Marijuana Cause Permanent Brain Damage in Adults?”

  1. VastSupremacy says:


  2. saw141 says:

    Really weird speech in this.

  3. Ray Richmond says:

    this is retarded

  4. Martin Altmann says:

    I agree that some can have predisposed brain structures that increase the chance of drug use that makes their grey matter volume smaller. It’s a double edged sword. Hippocampal volume is reflective of the difficulty to activate the reward center.

  5. Martin Altmann says:

    If you could choose to activate pleasure at any time without any work, complex memory from the hippocampus is no longer needed, thus causing decay of grey matter. This would happen with any addiction such as to sugar, caffeine, cannabis, sex, video games or more dangerous addictions such as opioids and amphetamines.

  6. Ravenous Wolf says:

    Who didn't already know that abusing substances can lead to irreversible brain function. Nobody smoking 3 joints a week would have an issue with brain and memory function.

  7. Damian Damianio says:

    It makes me more productive and learn easier. How does everyone keep saying it lowers iq and creativity? Obviously creativity is increased there just is no scientific measurement for it

  8. Future Hendrix says:

    Honestly if you smoke just to get high than it’s just going to have a negative impact on you depending how often you use it I’m pretty sure we can all agree on this statement

  9. scope flash says:


  10. MayorOfMoetown says:

    they all seem like retards to me. + all have a sophomoric obsession with it.

  11. steal threaded says:

    I actually went up significantly on IQ tests because of the increased focus weed gives me.

  12. Daniel Sanchez says:

    …so I have brain damage then.

  13. Paul Derrick says:

    I've been smoking weed everyday for the past 3 years and I feel like I'm superior to everyone else so I'd say that's a pretty good long lasting effect

  14. Kyng Kraken says:

    F U we have to impair shyt when you know enough truths about America and this world and how evil it really is and how our kids have to live in a world like this

  15. 我是龙Jay says:

    It all comes down to MODERATION. Too much of anything is bad. I use to smoke every day, all day long. Now I go weeks, even months without smoking and normally smoke for an entire weekend then stop again.

  16. gktjq149 7 says:

    Research is just a research. Find it out yourself. Not smoking marijuana is always better than smoking it. It makes your daily lives boring so you gotta depend on it and this becomes the endless cycle of self-destruction. If you can smoke once every week and stick to it then go ahead but most people will end up smoking more than they should .

  17. LosAngelesWeedSmoker says:

    Dabs give cancer, fact.

  18. Lucky Bass Turd says:

    This may also be a bunch of Bullshit compiled in to a video, it might be propaganda… we might or may need to know more before acting like you are stating facts…but the sheeple don't hear words like might & may ,they see your Lab coat YouTube channel & agree with you. SMH , smoking a little weed to see thru all the brsinwashing BS ,is totally worth it!

  19. DatingFairies says:

    Whoever belives weed damage ur brain their brain is already damaged

  20. Kottonstream says:

    Lol I’ve been smoking since I was 15 everyday all day . I am now 41 . I can safely say it doesn’t do any damage to your brain . I say it comes down to the individual. If the person was a loser before smoking then they’ll be a loser after smoking . . People need to just stop . Alcohol does way more damage to your body and brain . Same with bad food for you . I still don’t understand why herb is so hated and picked apart . But like anything in this world if it’s good or helpful it will be illegal . If it’s bad for you and will end your life faster it is made readily available

  21. Nick Sameowl says:

    I told myself to take a break for at least 4 weeks each time, and I did, sometimes more, sometimes less.
    Since 16, now I'm 18. I wonder if it has much impact on my brain, even though I take these breaks and if I should do less..

  22. Damjan K says:

    I see that you are only making anti-marijuana studies, but there are also studies for marijuana and cancer (glioblastoma etc…) it would also be nice to add a link to the studies in video description (pubmed etc..)


  23. Jap Joe m says:

    16 joints a day!, Sounds like someone needs to get some better smoke, lol ,peace

  24. FaithwalkerTodd says:

    I can think of No Other Drug or substance that the people have had to force the government's hand. The government is here because the people created it and gave it enumerated powers, outside of those Powers it has none. This is why they needed to pass a constitutional amendment to ban alcohol. It's just more proof that any ban on a substance is unconstitutional and the people pushing it should be arrested for all the damage they've done to society. Furthermore, their property should be used to pay damages to those who have been imprisoned and injured due to the crime created by increased prices for products that should be legal and relatively cheap. It doesn't affect me at all if somebody wants to smoke crack or heroin, but when the police enforce laws that make it more expensive, and it forces people who are addicted to the drug to break laws, that is a problem for me. That means that the law enforcement and the legal system is the problem that is causing the injury. Remove that problem and we will have solved the drug issue. Nobody should be concerned with what other people are doing in their house. If you are concerned with what other people are doing in their house then maybe we should come into your house and make sure that you have everything in order and legal. I mean, what do you have to hide?

  25. Murraay Murraay says:

    Is there any way to stop that permanent brain damage if I started in my teens?

  26. Ankhommon Supreme says:


  27. Mix N says:

    My junior year I started smoking weed daily before school. My grades went from D's to B's and A's. I doubt if it made me smarter. I was just so paranoid of getting caught I did my worked and didn't say nothing even did my work in class which I've never done previously.

  28. Mobile Players says:

    it does everything and it will kill yo ass

  29. E says:

    So is this a no? Or is it only if you smoke enough after 20 years.

  30. Saul Val says:

    Doctors don't want to help you cure anything. Big pharmaceuticals will lose money.

  31. N Neichan says:

    I wonder if this atrophy is connected with a specific component of the plant. Is it connected with THC, or CBD? Or is it related to SMOKING it? Any idea?

  32. moonskin1976 says:

    Its not the cannabinoids that are the problem, its the smoke. Another problem is bad science. Ive been taking cannabis oil for 5 years now. Cannabis oil saved my life and my IQ, coodination, logic and creativity have been enhanced, not reduced.

  33. david franco says:

    bla bla bla spark it up!!!

  34. Alan Ames says:

    This guy is a cunt

  35. Biuti Chile says:

    How about more risk for new psychosis (even not related to familial psychosis) on a cohort of ~4000 teens. JAMA June 2018 number. Stay tunned for the next nutritionfacts video on THC 😉

  36. J Priest says:

    Smoking is so yesterday. Vape. Eat Drink.

  37. Wayne Junior says:

    Mii'gwetch for your work, I appreciate you doctor Greger, have a wonderful day.

  38. Dr. Carp says:

    The point is that it does cause impairment and there is also a spectrum of reactions, people are chronic users, they aren't going to stop for 15 years to repair the structural changes noted. Also, please keep in mind that weed is becoming more and more potent as time goes by and these studies are going to rapidly be less reliable with the new potent strains. Not to mention these studies are very limited in scope. We do have entheogenic use in traditional cultures and in these cases it was not used except in very limited circumstances on a frequent basis. I am afraid that those limited studies outstanding, what we have going on is a widespread cultural delusion of it not having any negative effects at all and a widespread experiment of a great deal of people using it in ways and doses and frequencies that any traditional culture associated with its use would caution heavily against.

  39. seth .m says:

    Oops. Guess I botched life this time around 🤕

  40. crazy observations says:

    challenge accepted

  41. Mika Peltokorpi says:

    So the answer is: Yes.

    And cannabis trafficking to adolescents should be punished like trafficking tougher drugs like cocaine and meth.

  42. Lil Sleazyxxx says:

    Well I’ve been smoking since I was 12 and I still make good grades like all As in elementary and middle school and As and Bs in high school

  43. Jukke Boxx says:

    WIZ Khalifa smokes everyday and gets high. He's a successful man. explain this.

  44. Vegan Nurse Practitioner says:

    Its nice to see on paper what is seen in clinic. Remember, this is not the ultra-low TCH medical use marijuana, this is the High TCH Recreational Use Marijuana. Come on, did you think a toxic substance that can affect cognitive function crossing the blood-brain barrier would not be harmful? Ever wonder where the term 'swiss cheese affect' came from when people talk about the brain of older long-term alcoholics? The THC in Marijuana is no different, Toxic chemicals damage, luckily we can recover if not over done. Some of the 'exploring' that occurred as you were young (I was in highschool in the 70's) as long as it was not a lot should do no harm, but if you kept denying life's lessons into your 20's, then you may see the brain damage, or not…. 😉

  45. Isaiah Esparza says:

    Why did you talk like that.

  46. darrel jhonson says:

    the only link i can see between NUTRITION and cannabis is that I'm more likely to eat unhealthy when i'm stoned , sorry not sorry.
    -yes im baked , yes Im eating a large pizza with extra chesse.
    o shit by the way the link over there is a study from harvard.

  47. Tunny Bunny says:

    I had a friend back in college like 15 years ago at Virginia Tech and all he would do was smoke weed and he was still a very smart person, He would always smoke it whatever free time he had and i would say weed probably makes you smarter.

  48. dan the dorito says:

    I think if you have too much, it will reduce creativity, but when I have an optimal dose, I'm pretty damn sure that the creativity I experience isn't an illusion. I hear awesome pieces of music created on the fly in my head, in an effortless way, something I never get sober, even if I try. It feels like my mind goes with the flow more and will explore new trains of thought it otherwise wouldn't.
    edit; I'm interested if these studies controlled for whether or not people were having within the optimal dose range for cannabis. The biphasic dosing effect means high doses worsen symptoms, and I suspect most people don't pay attention to optimally dosing themselves.

    Some info on biphasic dosing if you're curious on what it means:

    Though there's also twins studies that don't account for the dosing, but found no noteworthy difference between a cannabis-using twin and non-using twin, with any shared decline instead being explained by family background factors the twin adolescents shared;

  49. Mr. Magic says:

    THC without CBD is dangerous

  50. TerminallyUnique95 says:

    The only way you can tell the effects on the brain is to look at the brain. SPECT imaging has. Many studies show areas of the brain decrease activity over time with marijuana.

  51. Tom says:

    What if you only smoke it once every few months, would that also cause damage. Also, what about bongs, are they better or worse for your health than joints

  52. Godly King says:

    Answer: Fuck no.

  53. Ghost says:

    Why does this dude sounds like he is high?

  54. Carl J Carlin says:

    Tobacco smoking is unhealthy. Electronic cigarette smoking is unhealthy. Marijuana smoking is unhealthy. Don't encourage children to smoke.

  55. Templar Knight 13 says:

    Weak people need drugs to feel better its ok

  56. Dock Gee says:

    You people who defend smoking weed every day all day are sick, stop the BS, weed is addictive……..I should know, I quit after thirdly years of heavy heavy smoking , DUI is the only reason I stopped, the drug testing, fail jail, there!!! Do I feel better after 8 months clean? Fuck yea!!!! Will I smoke again? Yes, it's my choice, so I can do what I want! Do I wanna smoke like before? No, I must be strong minded, or fall asleep again! It's so easy to let the weed have my body and mind! I love her, I'm just free of her at the moment! Jane will never brake up with me, but I could leave her though

  57. Temsha Sanaie says:

    From my personal experience, cannabis has made me more clever and open minded. At the same time its difficult to memorize information

  58. Jason B says:

    lol this guy has a nice personality.

  59. Tony Tay says:

    I smoked from 15 to 21 (2001-2007) and I see at work that I've issues for memorising and concentration. I'm a bit worrying. I gave up long time ago but still. I cannot understand how we have people that are still saying that smoking is not bad for you.

  60. Brittany Blake says:

    I like the way information is broken down in your videos with the upclose highlights of the research studies…what type of software or editing software is utilized to produce this effect?!

  61. Larry Tate says:

    Basically we don’t know yet.

  62. Marcell Gyurján says:

    the dude reading this was high all along

  63. adamaj says:

    It's not the marijuana's fault. It's more of a "if you don't use it, you'll lose it" kind of thing. When you're high you don't do things conducive to stimulating and exercising the brain. In other words, I bet if they had a control group that did everything the weed smokers did except smoke weed, then their brain performance would go down too, just like the taxi driver in the video.

  64. plant hobbyist says:

    ok thanks

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