Cannabis Use Produces Persistent Cognitive Impairments

Summary: Cannabis use leads to cognitive impairments that extend beyond the period of intoxication.

Source: Society for the Study of Addiction

A systematic review published today in the scientific journal Addiction has found that cannabis use leads to acute cognitive impairments that may continue beyond the period of intoxication.

This Canadian-led meta-review (review of reviews) merged the findings of 10 meta-analyses representing more than 43,000 participants.

The study found that cannabis intoxication leads to small to moderate cognitive impairments in areas including:

  • making decisions,
  • suppressing inappropriate responses,
  • learning through reading and listening,
  • the ability to remember what one reads or hears, and
  • the time needed to complete a mental task.

“Our study enabled us to highlight several areas of cognition impaired by cannabis use, including problems concentrating and difficulties remembering and learning, which may have considerable impact on users’ daily lives,” said the study’s co-author Dr. Alexandre Dumais, Associate Clinical Professor of Psychiatry at Université de Montréal.

This shows the outline of a head
These and other acute impairments mirror the residual effects documented for cannabis use, suggesting that the damaging effects of cannabis begin while it is being consumed and persist beyond that period. Image is in the public domain

“Cannabis use in youth may consequently lead to reduced educational attainment, and, in adults, to poor work performance and dangerous driving. These consequences may be worse in regular and heavy users.”

Cannabis is the third most consumed psychoactive substance in the world (after alcohol and nicotine) and adolescents as well as young adults have the highest rates of cannabis use. 

Recent global changes in the legalization of cannabis suggest that public perceptions of its safety and acceptability are on the rise. 

It is therefore important to understand the cognitive risks involved in using cannabis, especially to young people, whose brains are undergoing significant developmental changes. 

About this cognition research news

Author: Jean O’Reilly
Source: Society for the Study of Addiction
Contact: Jean O’Reilly – Society for the Study of Addiction
Image: The image is in the public domain

Original Research: Open access.
Evidence on the acute and residual neurocognitive effects of cannabis use in adolescents and adults: A systematic meta-review of meta-analyses” by Alexandre Dumais et al. Addiction


Evidence on the acute and residual neurocognitive effects of cannabis use in adolescents and adults: A systematic meta-review of meta-analyses


Cannabis is among the most consumed psychoactive substances world-wide. Considering changing policy trends regarding the substance, it is crucial to understand more clearly its potential acute and residual adverse effects from a public health viewpoint. Cognitive function is one of the targeted areas with conflicting findings. This meta-review measured the magnitude of acute and residual effects of cannabis on cognition in adolescents and adults provided by meta-analyses and evaluated quality of evidence.


A systematic search was performed in PubMed, PsycINFO, Web of Science and Google Scholar. Meta-analyses were included if they quantitatively examined the performances of users from the general population on cognitive tasks.


The search retrieved 10 eligible meta-analyses (71 effects sizes, n = 43 761) with evidence ranging from low to moderate quality, which were categorized into domains of cognitive functions: executive functions (k = 7), learning and memory (k = 5), attention (k = 4), processing speed (k = 5), perceptual motor function (k = 2) and language (k = 2). Verbal learning and memory displayed the most robust evidence and were most impaired by acute cannabis intoxication that persisted after intoxication passed. Small-to-moderate acute and residual   adverse effects were reported for executive functioning. Cannabis use led to small deficits in inhibitory processes and flexibility, whereas small-to-moderate deficits were reported for working memory and decision-making. Evidence regarding processing speed and attention has shown that cannabis administration induced small-to-moderate adverse effects and residual neurocognitive deficits were observed in heavy cannabis-using youths. Results showed no significant difference between cannabis users and non-users on language, and small-to-moderate effects for simple motor skills.


Meta-analytical data on the acute effects of cannabis use on neurocognitive function have shown that cannabis intoxication leads to small to moderate deficits in several cognitive domains. These acute impairments accord with documented residual effects, suggesting that the detrimental effects of cannabis persist beyond acute intake.

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  1. The title of this article is so unbelievably deceiving, especially considering most people read titles like that, never open the article, and start spewing variations of the title statement as fact. Come on guys, there’s plenty of real data out there on the negative effects of weed use, so the fact that you stretched this nonsense so much just shows the writers had already decided what they believed and we’re looking to interpret everything as such. There are so many better arguments that already exist with evidence, I don’t know if this is considered a scientific journal, but based only on this article (which we should not truly evaluate this source based on a single article obviously), you have no right to consider yourself such.

  2. How do you try to talk to someone who smokes cannabis almost nonstop on a daily basis that their behavior is greatly affected by their cannabis addiction? This is a 48-year old female.

    At this time I cannot discuss the subject with her as I feel that I cannot discuss the matter with her as she is helping me at this time.

    I have never smoked cannabis or even cigarettes for your information. This may not be relevant but just wanted you to know.

    If you could give me some advice on how to possibly help this nice lady I would be most appreciative if you could advise me about her.

    1. I am literally medicated from Cannabis as I type this, the lack of acknowledgement for the global use and abuse of the psychoactive bean with loads of caffeine surmises the lack of insight being put forth with these types of ‘studies’.

      Sadly Cannabis and all it’s associated benefits be they for medicinal/recreational or industrial use has been on a global level handed over to multinational Corporations and the all caring ever loving Pharmaceutical companies, of course for the greater good but I digress.

      In my 55th year and for whatever reasons Cannabis use has been a 44 year relationship that has not effected my overall health & wellness being that I have also invested a great deal of time and efforts to run several businesses, invest in the well being and physical fitness of not only myself but as a coach and trainer of varying sports since 1986 as I have always believed that our first wealth is our health and we need to invest wisely.

      Our over health & wellness in life is attributed to 80% lifestyle choice and when looks at the 4+ decade long global Obesity epidemic one can easily see that most are making choices that impact their health based on being lazy, or sadly as our food has denigrated over those years as well, relying on processed fake foods which themselves contribute to dis-ease.

      Mandating fitness programs and/or incentives to participate in physical fitness while providing people with cheap nutritious foods would acerbate many health related issues that strain our healthcare systems.

      But than again I could easily be stereotyped as a unmotivated stoner going nowhere in life.

      May the day bring with it compassion and kindness as our world certainly use more humanity and understanding.
      ~Buddha Sadu Gains
      BOA Farm
      Drill Sargent BOA Fitness
      Pelican Perspectives

  3. How do you try to talk to someone who smokes cannabis almost nonstop on a daily basis that their behavior is greatly affected by their cannabis addiction? This is a 48-year old female.

    At this time I cannot discuss the subject as I am being helped by her at this time due to bad winter weather. She could not allow me to stay in my car at this time and is allowing me to stay in her apartment until the extreme weather improves.

    You probably have concluded that I have no where to live; I was never late on my rent where I lived for 5-1/2 years nor have I ever been late with my rent where I have lived before. I am a 70-year old WF who has never been in such a position as this before in my life. I also have lived alone most of my adult life although this may not be relevant.

    If you could give me some advice on how to possibly help this nice lady I would be most appreciative.

    1. I imagine that you might feel you need not to concentrate on your predicament and someone else’s but she is the one that has a house and is putting roof over your head so you need to concentrate on getting yourself some help so that you don’t have to live in your car. First things first you need to not be living in your car cuz you’re lucky to have this person to get you off the street so you don’t freeze to death. ✌️❤️?♥️??✌️?❤️❤️ Bless you best wishes

      1. Weed hurts people. Sad fact is our outcast class looks for the niche to fit into. I was there. Such a lonely rejected place to wonder in. Folks if you are not smart or not physically in tact, self harm is not the answer. Know that everyone hurts. Hang on. Each of us finds our place. Work on keeping yourself physically fit and mentally prepared. Your moment to succeed will come. If you can not break through you will just be a loser. Be ready to fight through. Plan on winning. I did. Hope to see you on this side.

  4. I know a lot of people that have smoked since their teens and still do today. And so many successful deans list students in college. This is a perspective that I agree with only in the same sense that alcohol impedes and reacts to people differently!

  5. So in other words, weed gets people high. I do not think we needed “systematic” research to make such a breakthrough. However, what make this article so vapid is its complete dismissal of marijuanna as anything other than a mental depressant.
    Using “cannabis” as an umbrella term for every strain of marijuanna in the world is a convenient fallacy. There are two primary strains: indica and sativa. Indicas are more famous as the “relaxed” high, often facilitating sleep or reducing generalized anxiety. Sativas are more stimulating, boosting energy and focus while also reducing the symptoms of major depressive disorder.
    So why were strains never mentioned as part of these experienents? Were patients given indica-dominant strains or sativa-dominant? Your “research” into these experiments is vague and too full of jargon to discern any meaningful discourse other than of how detrimental cannabis is to mental health of anyone using it.
    And if you still aren’t sure about giving marijuanna any credit whatsoever, go to a damn dispensary and talk to any of the patients. They will tell you the transformative impact it has had in their life. To say cannabis produces persistent cognitive impairment is essentially calling the hundreds of thousands of medical marijuanna patients mentally impaired.
    If the word “cannabis” was replaced with “alcohol” throughout this article, I probably would have learned just as little. It is as lazy and unproductive as studies come. Misinformation at its finest.

    1. I imagine that you might feel you need not to concentrate on your predicament and someone else’s but she is the one that has a house and is putting roof over your head so you need to concentrate on getting yourself some help so that you don’t have to live in your car. First
      things first you need to not be living in your car cuz you’re lucky to have this person to get you off the street so you don’t freeze to death. ✌️❤️?♥️??✌️?❤️❤️ Bless you best wishes

  6. I’m sorry, but I beg to differ. There are stains that induce relaxation and do help people with PTSD to not “remember” or to stop acute flashbacks. There are also stains that induce action. Sativa’s bring patients to a place of functional ability they otherwise wouldn’t have. Indicas induce a calming, relaxing effect. And hybrids tend to be somewhere in the middle. However, as a medicinal cannabis user, I can say for certain, some stains are meant to relax, calm, even induce sleep. You wouldn’t be in a position to have to be reading, driving, or trying to accomplish many tasks while using these. Sativa, however, leaves me highly functional, having better ability to complete tasks I would otherwise struggle to do, or be too depressed to do. Or you anxious to do. Too stressed to do. Too scattered brained to do. Every strain is different. So is every brain, and every patient. It’s about knowing your limits and respecting the medication for what it is. I’ve never been as highly functional, though, as I am with my medicinal cannabis.

    1. This comment is to Rachel and everyone that it seems there is an agreement on this much when they claim to have done research it’s very vague they don’t specify anything as to what strain or under what conditions none of this sounds to me like they just tested it on young people. I worked in the pharmaceutical industry for years and believe me it’s just way way too bad that they never researched all the opiates being handed out like candy and all the methylphenolate handed out like candy to parents and grandparents of three year olds for the last three to four generations. And then everybody kind of wonders why we have all these people who don’t care. I have to agree it’s always slanted in a direction that makes it still seem okay to be taking pharmaceuticals but dismisses medical dispensaries for cannabis and the people that has helped to get off of these wicked pharmaceuticals that have destroyed families for decades but I digress. I’m just saying we all know who funded this research and I don’t even know if my comment will get published because I made that statement but hopefully it can open some eyes. Thanks to everybody for speaking truth on here somebody needs to when they come out with studies like this. ✌️❤️?♥️??✌️?

  7. I would like to see your clinical data for the 43 thousand subjects that are claimed to be involved in this study. I would also like to know how long the subjects were evaluated and what other potential influences were involved which not reported.

  8. Then I must’ve been a genius when I started, and a moron now! Because I’ve been smoking weed for 45 years, and I feel just fine!???✊

  9. Lmao I love these “studies” been smoking for 20 years am very well mannered can learn and remember things and new topics just fine It affects people differently but still havent lost any cognition in my 20 years. try again.

  10. Oh yeah, because those are such horrible side effects. Compared to liver damage, domestic violence, OD, and withdrawal symptoms that can kill you alcohol is sonkuch better. Stop demonizing marijuana while alcohol is responsible for millions of deaths, violence, and disease.

  11. I am sorry you think this study is true to fact.
    I come from a long line of dementia and Alzheimer’s disease in my family marijuana does not stop different taking or learning or remember it from the aluminum cans and aluminum foil that they use for so many years that caused them to have this disease I am lucky and blessed that I am the only one in my family that does not have the genetic for Alzheimer’s and Dementia please quit saying that everything is face against marijuana because marijuana is in the ability to eat but I don’t want to eat it helps him to sleep when they can’t sleep so you don’t know what you talk about and quit giving false information you may think you’re a doctor but I tell you what has a patient has been using it for over sixty years I hate to tell you you’re stupid because I have an IQ of over 200 and I’m not stupid and I have a break and I have a medical degree you are the stupid jackasses that don’t know what is a 43,000 people that you supposedly did this on in Montreal you’re not a part of America may be done it’s this stupid Canadians

  12. Totally disagree, since writer only show one side of cannibis use. And for certain people who are not able to use cannibis. They can use CBD. And then you can tell the difference. If the world is up side down. Dont blame on cannibis. Thank you

    1. Yes Sister…they never put the good uses. Until they stop drinking to relax the mind my ears are closed. Who do they think they’re fooling?

  13. I’ve smoked for around 45 years and have not had these problems united I made the decision to. Many people I know are the same. Who paid for this research

  14. Where are you finding these “test subjects”? I believe your information to although be informative its also completely false. You want a real Guinea pig to study sign me up but please don’t spread more propaganda against marijuana. I’ve been smoking all kinds of different types of marijuana since I was 15 years old, daily since 18 for 27 years now and I can easily say I don’t have any of those issues and never had. My problem is I have been diagnosed with ADHD and live in a non legal state so because I smoke marijuana they won’t give me the medication required to heal it. Pharmaceutical companies are the problem, alcohol is a problem, meth is a pandemic, not marijuana.

  15. I am a 30 year daily user. It is all dependant onvthe individual. The first 7 years before total tolerance was achieved were the most fun. My friends and I always practiced abstinence from driving when we realized we were too inebriated. Though I have driven high so many times it is impossible to count. I have always felt I was a better, more aware driver when so. I even smoked at a driving job.
    The only truth to this article I would agree with is that it takes longer to recollect aome memories. After so many years I learned to mentally push through the fog to concentrate. Maybe that’s why I have extreme tolerance to the high. I mainly smoke now to aleve pain and help to sleep. It’s better than having constant nightmares when off for a while.

  16. I don’t agree with a lot of the content. Just like alcohol and nicotine. If used responsibly and in moderation, a person can enjoy the use and function well. I’ve been using cannabis for about 50 years. I have enjoyed a successful life, am a medical professional and continue studying psychology and human behavior as a hobby. So pardon me while I light up. Have a wonderful day ?

  17. If you want to talk about cognitive impairments. Brain damage is a common and potentially severe consequence of long-term, heavy alcohol consumption. Even mild-to-moderate drinking can adversely affect cognitive functioning (i.e., mental activities that involve acquiring, storing, retrieving, and using information)

    So anyone who drinks, which is most people, are at much higher risk of this than marijuana.

  18. People are not going to stop taking marijuana no matter how many negative reports get put out. The benefits outweigh thr negative. More and more people are saying NO to big pharma andd taking herbs which The Most High created for real healing.

  19. This is absolutely disgraceful. You cannot take a plant, and assume it’s all the same. Different strains produce different responses and there are some that increase learning and attention span, as many adhd users will tel you. Before you go publishing generic falsities, get the facts.

  20. Seems like yet another story to scare people away from the cannabis industry. I wonder if the 43,000 participants had smoked cannabis ever. It certainly sticks around longer for those who are not regular smokers. I am a regular smoker of cannabis. I can cook, clean, work math problems, I talk on the phone, wash/dry/fold laundry, tie my shoes, shower, brush my teeth, plan a travel trip, go for a walk, play catch, garden, laundry, make appointments, pay bills, put on makeup, draw, shop, plan birthday celebrations, and take care of my cats. I spread out smoking times and am careful to keep out of the drivers seat till my cannabis high feelings subside. I do not fumble or have any silly symptoms from my smoking sessions before doing anything dangerous or potentially dangerous, like driving a car right after smoking. But other non-dangerous tasks, I can accomplish soon after smoking. Like cooking, paying bills, balancing my checkbook, play memory games/trivia games and win! I have taken classes and passed with A’s! I have smoked cannabis over 10 years. It has not made me slow or caused long term incapacitation. It is not hurting me as much as alcohol could or even drinking too much water, which could cause death.
    When I smoke cannabis, eat cannabis, or place topical cannabis on my skin or bathe with cannabis bath salts I do feel the effects of intoxication. To deny that would be silly. But I exercise my brain with games, debating, math, dancing, and discern answers to problems in my life. My mind is not hindered in any serious or lengthy periods by cannabis. My body works well and feels more fluid when I smoke. I know smoking in general is unhealthy. Breathing in anything besides air is risky. So I plan to change to only eating cannabis, applying cannabis topically, or bathing with cannabis in controlled amounts so I do not overload my liver or kidneys. Humans are born with cannabis receptors in your brain. We are created with the ability and purpose to process cannabis within ourselves. If you intake reasonable amounts of cannabis it can help you move through life or calm some mental health issues. That said, I have some mental health issues (such as panic attacks, rage, anxiety, depression and ptsd) that showed up years before I made cannabis a major part of my life. I do admit if I am overly saturated, I am paranoid and easily depressed. But if I have a medium to small amount in my daily life, it calms the mental health problems and makes it easier to handle issues that rise up. I do feel a slight lowering of inhibitions after I smoke. It’s not enough to make me cause a scene or speak super inappropriately! If I drink alcohol, receive a prescription of opioids (and take them), stay up almost all night or all night from insomnia. My inhibition’s are very low. I speak in unpredictable ways. I may be inappropriate with my words and overly friendly/aggressive with alcohol and opioids. When triggered I can be less predictable, more reactive and a bit more dangerous while feeling terrified for my life. And I get stuck with the worst fight or flight feelings. This makes me unpredictably dangerous. Smoking cannabis creates a port in my mental health triggered storm. It calms troubles, has helped me retrieve memories, eat when I was depressed and could not force myself to eat. Smoking cannabis saved my life. I was 105lbs and started smoking after a break from cannabis. It helped me eat and stop passing out, from not eating. Keeps me from causing a scene and lowers my rage to a safer level. The cannabis helped more than anything I was prescribed for mental health. As long as I don’t overly saturate myself, challenge I’ll myself, and keep working to better myself (which I am) cannabis isn’t a hinderance. I won’t be a useless couch potato. I believe it is possible to intake cannabis on a regular basis and not be hindered with residual effects by the natural plant cannabis. It takes work and determination and is possible to be intelligent, remember, and not have horrible cognitive function! It takes working on yourself and not giving up.

  21. I appreciate the Society for the Study of Addiction, but this is incredibly boased. Perhaps they thought “Meta analysis” would hide that but it doesn’t. They can’t even describe how the supposed cognitive deficits are measured (science has never been good at that).

    The story and the Meta analysis are bunk.

  22. I call bullshit, dude went looking for specific results he found them. He gave no info on how he came to these conclusions and just wants to induce the reefer madness effect again but no one is this fucking stupid anymore.

  23. I guarantee I do not have a loss of cognitive thought and abilities. I believe my migraines cause more issues than all of the times I have used Cannabis.

  24. The study does not indicate what type of cannabis is being used, time of day, what purpose, amount. Although it’s a large study, before condemning it, perhaps add in these elements.

  25. I’m glad there are so many smart people reading this dumb research and calling it out as the false study it actually is. Thanks for speaking up!

  26. As a parent of young adults I remain concerned about the use of pod and the argument I get is that’s it’s legal! More education and puplication of the effects is necessary.

  27. “Society for the Study of Addiction” and I’m sure this study is completely non-biased. Completely free of funding-justifying bias. Why don’t they study an actual damaging addiction? Like, say, addiction to television or social media, those addictions cause far more damage to society than cannabis use – which has actually been shown by multiple non-biased studies to improve cognitive function. Now go write up a study that says OxyContin isn’t as addictive as is believed.

  28. I disagree with this entire article. I have been a cannabis user for over 20 years and it has in no way impacted my mental or cognitive ability to make everyday decisions, my workplace performance is not affected, I can drive without no impairments at all.And I have excellent short and long term memory. Not to mention I have a PHD.

  29. And they legalized this! I smoked pot in college (45 years ago) and all it did was make me lazy, unmotivated, and silly.
    I never liked that feeling.
    Everyone now argues about how benign it is.
    I completely disagree, and now here is a study that confirms it.
    I think it’s dangerous and now our I’ll advised leaders have legalized it.
    Now kids will get the message it’s ok and we’ll raise A generation of impaired kids.
    This is such a shame.

  30. This is the most idiotic article that has no science backing it. Cannabis use has been used as a medicine for millenia. Get your head out of your ass and stop promoting actual drugs like Xanax. Which actually gives you brain damage.

  31. I did uh, my own extensive research in the 70’s and 80’s. My conclusion was, Cannabis makes you stupid. It’s fine for mindless muscle memory type jobs but for anything requiring thinking or planning it’s the worst.

  32. WTF ever. Just another fake ass reason not to legalize on the federal level.
    Those of us that needs relief from something other than opiates.
    Let me guess, this study was at least partially funded by one or more pharmaceutical companies?
    I have PTSD, social anxiety, severe insomnia, and chronic severe pain.
    It has nearly become impossible to get pain medication, anxiety medicine (that works)from a reputable doctor because they are terrified of losing their license. Texas I think has legalized for PTSD but closest place is Houston, and still insurance doesn’t pay for the doctor that can legally prescribe, and doesn’t cover the cost or even part of the cost of the medication. Even if it did, that would have me driving to Houston every week to pick up for cannabis.
    Legalize it, take the proceeds and spend it on education, Healthcare, drug rehabs for those that needs it.
    If it wasn’t for family and my need to occasionally depend on them I would be Colorado bound (or another state with relaxed
    if not completely legalized) laws.
    They want to stomp out the opiod pandemic (which I’m for) but not willing to help us by allowing us to potentially replace that badly needed pain/anxiety/help with appetite
    during chemo/PTSD relief medicine in cannabis form.

  33. So all this for me to know what I’ve always known. Some shouldn’t smoke, especially if you’re dumb to begin with. I’m so high right now, I forgot what I just wrote…LOL. Tell you what, do a study comparing the horrors of alcohol and cannabis and then when you totally ban alcohol, which you will want to, we can discuss weed. In the mean time this is like criticizing a camp fire on the front lawn while the house burns down.

  34. The benefits of this natural medicine far outweigh the side effects and most man-made medications have way worse side effects than cannabis and they are still prescribed and sold to patients.

  35. I am a lay person,but after watching friends use it for many years this study is spot on! In my words it makes them lazy, apathetic, their morality changes, the judgement becomes skewed!! There are a few exceptions but not many!

  36. I would live to actually see what these studies say, and not you interpretation of them. These studies seem to be done on children, which I find strange, I’d like to see which group, the size of the groups, and the mental awareness of the subjects before hand.
    In no way do I believe children should touch any substance, and I’m super curious where these groups came from, and the who the control group consisted of. The fact children where given this us beyond me, and I’d like to know why and who was giving these tests, and who took the results.
    Cannabis is a drug, it can be good or bad, the same as alcohol or nicotine. The purpose of this test makes little to no sense,and it holds no data on adults, for medicinal or recreational use. Seems like propaganda to me.

  37. This article is so disgusting. I’m stage for it ENDOMETRIOSIS. CANNABIS HAS SAVED MY LIFE. Band-Aid pharmaceutical medications put me into the hospital more than a handful of times which would you take.

  38. Alcohol is much worse. For me Marijuana helps me focus and is great for my PTSD.I am a legal card holder.

  39. This article is trash. I feel like people are trying to make cannabis look like a bad thing now that they know it replaces many pharmaceutical drugs, with far less negative side effects associated with many of these drugs. I couldn’t help but laugh when it said adults with cannabis use may show a decrease in work performance and be dangerous drivers. You people act like pot heads are going to nod off behind the wheel like they’re on heroin or some bullcrap. I love that we have scientists that have never experienced cannabis at all trying to tell us how it is and what it does when they have no clue. By the way I smoke everyday before I go to work to kill my anxiety so I can be ready to help my customers everyday instead of letting my anxiety get in the way of it. So cannabis makes me a better worker, so put that in your all’s pipe and smoke it. HA!!

  40. First of all, I smoke weed everyday. It actually helps me with my pain so I can do things that my pain meds won’t let me do. No I don’t drive when I smoke, that’s like when I drink,I don’t drive. I’m not stupid… Yes I have mental health problems. Yes it helps some. But the main thing is if it wasn’t for cannabis, I would be addicted to pain meds cause what I take is very high powerful stuff. People don’t think about it, but cannabis just might be better than pain meds, cause people are overdosing on pain pills, killing themselves when all cannabis does is put your rear end to sleep. But I don’t abuse it either….

  41. Like this is something new.
    These symptoms looks very familiar to how President Biden acts. Not sure if he was a pothead in the 60s ,but sure looks like it.

  42. In regards to the article concerning negative cognitive effects of cannabis, I was wondering who the ” average user” is?
    Are there at least a few subjects who offset these expected side effects with OTC cognitive enhancement supplements?
    Perhaps, instead of eliminating a safer, vitally necessary source of pain relief and digestive system soother needed by so many patients, it might be better to find counteractive agents, preferably also natural, to replace nutrients that may be depleted from ongoing use.
    There are unwelcome side effects from most pharmaceutical drugs and they use this method of counteraction to enable patients to take the medicine they need, while reducing or eliminating adverse side effects….theoretically anyway. More open ended studies are needed.

  43. marijuana in compared to alcohol is way healthier and definitely has less impairment capabilities.

  44. Then how is it i not only passed high school with high honors and carriied a 4.0 grade average through college, went on to get a masters degree in science and engineering and i have smoked Marijuana daily the whole time? Answer me that one?

  45. BS. I have done physical and mental experiments on cannabis my whole life. The only down fall to cannabis is dry mouth ( cottonmouth) & over eating junk food (munchies).

  46. Woah, this is a bunch of malarkey. This seems pretty biased or even paid for. Most of this research is definitely not true to the slightest degree. I’ve gone undiagnosed with attention deficit disorder up until my early 20s and cannabis has helped tremendously with my math skills and comprehension more than the prescribed medication for ADD.

  47. In terms of medical marijuana when are researchers going to be able to identify strains and dosages for the list of approved diagnosis that targets specify needs? I’m assuming once the federal government drops the schedule one so how was this study approved? Thanks, signed a curios health sciences student.

  48. I been smoking marijuana for about 37 years I have to beg to differ’s a plant grown from the ground ..the most bad affect from it is you can get fat cause you get the munchies …not one time have u heard people over dosing..and as far as the learning capacity I don’t think it unpaired my decision on things not learning new or old things. .. everyone has the right to their own opinions but maybe the government should listen to the people

  49. This is good to know, but why is there no data about how long those residual results lasted shared with us? Surely some of the studies in the metanalasis must have tested the participants more than once after the acute high was over? I don’t see how one is supposed to make an informed decisions about the risks of smoking cannabis if that factor remains unknown.

  50. LMFAO You litterally listed all the things we stoners already know. Also it isn’t nearly as bad as say alcohol, so whatever.

  51. Hahaha yeah this is a bunch bs… I’ve been smoking it for many years and if it wasn’t for it, I’d still have seizures and I also think more clearly,I also get my shit done a lot faster without my hands from arthritis hurting.. what nonsense..

  52. What were the prerequisites for the patients involved in the study. Were the cognitive function of the patients determiñed before induction of cannabis? Had any of the patients had any prior use of cannabis before the study?

  53. Review of reviews? Worthless study with biased results. Paints a small, and incorrect, picture of
    Marijuana that helps millions with functioning with their varying conditions

  54. Bullcrap, I myself have been using for many years,, and I’d really like to particpate in one of these studies. My dexterity and memory is probably greater when stoned, definitely more creative.

  55. Very weah article and study.Only few affirmations without exposing any trustable scientific methology.
    No serious statistic analysis.
    Sounds more like a propaganda than a scientific paper.
    Embarrassing that this site give echo to a such poor research.
    This trend to publish weak studies is weakening the scientific methology.

  56. Bullshit. I hate when these nerds with nothing else to do but hate on cannabis. You know someone in that group is getting stoned off his ass! Focus on the good…please.

  57. Based on personal experience and observation I will have to say that I disagree with this.
    Wait… What were we discussing?
    Who am I?
    What am I doing here?

    You can’t really be serious.

  58. While I do understand the reason for this study, only 43,000 people participated in this study. Try 1,000,000 participants next time, and compare willing to say that the results would be the opposite. And cognitive abilities would be increased in those that do trade work for a living. ive been a canabis user for 27 years and I’ve experienced none of the above.

  59. I have been a long term heavy user of cannabis and I don’t agree with the study. I know scientist, doctors and teachers who use. To clarify smart hardworking people use cannabis. it’s a better medicine than most

  60. I’m experiencing this but I don’t use cannabis. Could it just be the stress that lead to cannabis use?

  61. Explain why I smoked every day of my life since I was. Have excelled in school, have a masters degree, been a straight A student, and a very successful career? I have not been impacted negatively by my use at all, in many ways it has lifted me up and helped me achieve sicess, it opens mind up and I can multi task better, I even faster with my relfexes when under the influence. Reality does not fit your science.

    1. If you’re such a genius why is your spelling and grammar so terrible. You never end a sentence with the word “was”. A statement doesn’t end with a question mark.
      You’re kinda proving the article correct.

  62. All these people with these so called studies never smoked weed I for one have been smoking weed since 15 I’m 55 and has never experienced any of this BS in this article

  63. Total trash, I’ve been smoking for more than 30 yrs.. wait, what were we talking about?
    Jk, this is the worst misrepresentation of the effects. Although I’m super dyslexic I find learning very easy even though I can’t really sit down and actually read a book I can read a tech manual and learn all I need. I think the issue wit this study is they purposely went out to find the dumbest hippies they could find to sleep this so called “study” everyone I Know is extremely successful and very smart. Sorry about your absolutely incompetent study.

  64. I have known of this for 50 yrs. As my husband started using in his teens and could not use his thight processes at all. A life wasted. All friends that are users never could hold a job and became recluses in their 50s. Ir have been suicides

    1. Lmfao you can’t be serious right now. People that smoke pot don’t give up on life and become reclusive and commit suicide. I don’t know what kind of drugs your husband and his friends were on. But I can assure you they weren’t smoking cannabis lol ??

    2. Your comment doesn’t sound very truthful. It sounds like the people you are talking about must have had other problems than just using cannabis. Most of the people I know that use it happen to be successful and professional as I am. Have a good day ?

  65. What a load of misinformation. I’m 74 and have been smoking since July 7, 1966. I’m a professional musician and can still remember the lyrics to hundreds of songs, which I perform nightly. The test subjects must have been morons to begin with.

    1. Exactly, as they do not show cognitive function prior to the study, so where is the “starting basis” for function. Maybe they couldn’t process these same ideas to begin with.

  66. I call bs in this study. I’ve been smoking cannabis for 28 years since I was 12. I am a physics major and I practice martial arts regularly. Cannabis has never negatively affected me doing either of those. Some of the smartest scientists in the world smoke cannabis. If you believe this study then enjoy being a sheep…smh

  67. I found out I was extremely allergic to marijuana after merely kissing a girl who had smoked a joint hours before. Just from the pot resin on her lips. The future of legalization really scares me. I cannot even shake hands with folks who use CBD oil.

  68. Do more articles on alcohol consumption effects. But those articles give no attention?

  69. They find out that strains of hemp are more effective than the vaccines in the fight against Covid and negative propaganda immediately ensues. Shocking.

  70. As a long time cannabis smoker i can say that this seems extremely fishy
    The side effects that they named off can be attributed to withdrawal and or intolerance
    People who do not smoke cannabis are more likely to have longer lasting effects due to there intolerance
    Take alcohol for instance we have some people who drink way more than what a first time drinker can handle and they get over there hang overs faster to where as with first time drinkers there hang over lasts significantly longer even though the alcohol is completely out of there system
    That all being said this means not only do long time drinkers get it out of there system faster they also recover faster
    The same thing applies with cannabis user’s so i know that already takes a big chunk out of the supposed 43k people they where talking about because there’s no way they managed to accurately find people who not only have been smoking cannabis for prolonged periods of time but also all have similar tolerances to cannabis
    I get that that’s why there’s 43k people but the fact of the matter is just like with alcohol some people shouldn’t smoke cannabis because it will negatively effect them
    The other thing i didn’t see being mentioned in this article that really made me question it was that the number of people who went cold turkey weren’t mentioned
    Once again just like with any drug of any kind the withdraw is just as important even for a tame drug like cannabis
    If you just stop all of the sudden your body will have long lasting effects that do lead to you basically still having some of the cognitive effects that you normally would while high
    It angers me to see that instead of actually informing people of how to actually wing themselves off the drug they instead only named off the aftermath of the drug
    This article could lead any current cannabis smoker to try and stop all together with no idea that there basically initiating the vary thing there trying to avoid only furthering the distain on cannabis and not correctly informing people of the effects cannabis has on a person
    Ie: this article can be classified as dangerous information if not corrected
    I don’t mind if it stays up because cannabis can cause cognitive problems if used improperly however it should be stated properly in order not to cause real problems for uninformed people later

    1. That’s just like me I’d been smoking for years. And I take very high powerful pain meds. The cannabis helps my pain more than the meds do if it wasn’t for cannabis I would be addicted to pain pills, possibly overdosing on them. But at least I can do more with the cannabis, cause I’m not in that much pain…

  71. This article mentions that cannabis is third among psychoactive substances used by humans, behind alcohol and nicotine. However caffeine is also psychoactive, and I assume that is above all three. It doesn’t change any of the points being made in this article, just flagging this for accuracy.

  72. So it really doesn’t say anything aside from when your high your high and you might be tired the next day.

    Give it up how can scientists put so much effort into proving that cannabis is bad but come up with no information that we didn’t already know.

  73. I Kimberly A Sample say that everyone’s experience is different ,I know people that it works opposite on ,them for instance they would become mildly paranoid and focus on everything in sight ,even a fly on the wall , everything would be like magic to them ,they get the hungries,they would get the giggles and laugh all the time ,so I Kimberly A Sample would say that’s why research is show important ,everybody is different,some people are not cognitive decline ,it’s cognitive stimulation,and that would be the importance of the voluntary research.

    1. Yeah I know right. I was thinking wow it makes me such a shitty worker I wonder why they promoted me and made me a store manager then. Lol this article is dumb dude, if I had to guess all these doctors and scientists are just trying to make pot look bad because people are using it instead of these crappy medications with terrible side effects and big pharma isn’t making as much money anymore.

  74. What is the effect of alcohol on the brain? Bet you it’s much worse than cannabis, you hypocrites!

  75. Did these participants have any underlying disorders?? Because with ADHD I believe cannabis helps more than legal methamphetamine… why would you give a person an upper when they already have an upper ish disorder? An ADHD mind is already going a million miles a minute, giving an upper on top of that causes chaos in the brain.

  76. I have been smoking Marijuana for 50 years and I have a really good memory of everything still, I think you need to do more studies.

  77. Having spent years of my life on cannabis, off cannabis, and revisiting it from time to time, I have theorized cannabis opens a hidden compartment in the brain so to speak. There are things I remember when I’m under the influence that were learned while under the influence, and obviously things I have learned while not under the influence that are forgotten once under the influence.

    I dont think this subject is as simple, nor as black and white as it appears on the surface. For instance, cannabis affects people with A.D.D. in positive ways that normal brains do not react in the same manner.

    Bias should be put aside when examining what this plant is capable of and surely not over simplified without explaining to the reader all the variables of cause and effect open the vast scale of mental health.

  78. Releasing a blanket statement doesn’t seem scientific at all. Where is the research data. How long have the scientists been conducting the research? What type of research was conducted? Did they use double blind studies? Did they conduct cross cultural studies? Are the results only in Canada?

  79. Notice how there’s no mention of how long these effects last after the period of intoxication, no mention of how acute intake is being defined, and little mention of the actual methods used to select the meta-anlyses beyond the types of comparisons they made. Is the study suggesting acute ingestion leads to permanent function loss? Further, these are hardly the full spectrum of cognitive tests.

  80. It’s funny how all holistic medicine that the Niiji used before the arrival of the Europeans that worked fine seem to now cause problems. Is it because the chemicals they put in the air damage the soil causing herbal remedies that worked before the 1800s to now have side effects? I just find it weird the list of medicines my ancestors used for centuries now have side effects.

  81. Bullshit. Ive been smoking since highschool graduated with low b. Went on to computer programming where i was pushing a a average. Now im a carpenter. Ive been a carpenter for about 12vrs. I have three daughters have to make decisions and remember places numbers times recipes. So to read this so called study is absurd.

  82. The article states that…

    “Cannabis is the third most consumed psychoactive substance in the world (after alcohol and nicotine).”

    This is incorrect, as caffeine is the most widely consumed psychoactive substance on the planet, therefore making cannabis rank 4th on the list.

  83. Not really shoxking but it should be contrasted with regular alchohol use, smoking, and football concussions statistical effect on cognitive ability. Im going to guess none of them contribute poaitively to the growing. Not sayi g qe shouldnt be aware of the dangera but lets not look at it in a vacuum.

  84. This entire article is the biggest load of s*** I have ever read.

    Almost as bad as all the covid misinformation the government wants to peddle down your throat.
    This is the same level of fake news as we all have seen in the last 5 years.

    The stupidest people I have found in my entire lifetime are those who indulge in alcohol. The most intelligent people I have known are usually every day stoners, they tend to retain alot of information and are more widely available to lots of different material to retain because they like to sit and discuss relativity in general and a large variety of information passed from one to the other.

    I don’t smoke or drink. However I do prefer the company of higher intellect. Turns out 40 years in and most of them turn out to be average every day stoners that can hold a conversation on quantum physics while also being able to break down almost every aspect of the physical body science.

  85. I think this depends on person. I’d love to let someone do sane study on me. With all my heath issues it helps me focus.

  86. I find your findings to be secured by right wing politics. Further more i can find that mind expanding Drug’s to be boon to psychiatric Dr. So in closing I find your options to be closed minded Fascism! Love Dr. Phill it.

    1. Oh Sarah. I LOVE being called a Doper. What a huge compliment! Dope is sacred medicine whether you choose to agree or not. So cannabis will go on healing and bringing homeostasis to the minds and bodies of enthusiasts all over the world.

  87. This is hilarious and absolutely wrong. You cannot define cannabis as a whole when there are subspecies and strains which produces various effects on the body. You completely ignore the method of which it is ingested and so many other variables that this is just a long running joke. This is pathetic and only implies you can be absolutely impared by cannabis which it’s the opposite. Cannabis heightens your senses and makes you more away of your surroundings. You become more self aware and are more careful. This article and the people behind the study really need to do actual research if they are going to learn anything about this plant. If anything you have shown to so many that you have no idea what the hell your talking about.

  88. Funny, caffeine is the most addictive and used psychoactive drug in the world and it didn’t even get a mention in this….I smell an agenda

  89. Great,I need more, people su#k, see I smoke pot and I still know how to use hashtags,I’m not that impaired and I’m 63, fool..

  90. That is false. Everyone is different I am a heavy user and my body and mind Tolerate the high and I’m still focused and sober feeling. Every person and age is different. Stop judging everyone is the same.

  91. It’s comforting that this kind of information is being-Hottest trophy wives ranked!!- what was I saying?

  92. Doesn’t say how long the effects were, just that they were present after expected time. Also doesn’t say to what extent or what the second test (post inebriation) results were – that is, what the extent of the disfunction was.

  93. And now it’s legal. It was much weaker back in the day. I’m sure kids and pets are coming into ERs with a cute intoxication from mommy and daddy’s candies left around when they were zoned out

  94. Can someone compare these long term effects to the long term effects of cigarettes and alcohol? Would be an interesting read, I’m sure.

  95. I constantly see studies about the negative effects of cannabis. I would like to see studies about cannabis use and how it helps slow down the thought process to the ability to be able to think better, slower, to be able to observe life easier. I have observed that it helps people like myself and others with mental health issues calm their brains down to relax and order to communicate, be in social networks, and to just be able to think without constant jumble in our brains. This is where I would like to see your studies go.

  96. Small to moderate effects in a paper that analyzed data of low to moderate quality. Meaning a decent likelihood that there’s statistically significant data which isn’t clinically significant.

  97. This is a horrible study and a lie. I started smoking cannabis in 1969. I didn’t get to college til later in my life and graduated with honors in 2004. It’s too bad bias

  98. Has anyone considered the benefits or trade-off there might be in having a reduced cognitive capacity? E.g. there is a lot of anecdotal evidence that smoking pot induces a state of relaxation, greater appreciation for aesthetics, and even spiritual insight. Perhaps less ambitious, more chilled out people is a good thing?

  99. This should be compared to anticholinergic disorders, which often accompany plant based supplements. These adverse effects may be mitigated through a simple vitamin.

  100. Yeah no sh!t it’s called being a stoner. It’s not something new us stoners told people about this years ago, but nobody listens to a stoner. If you want answers just ask. No need to spend million on scientists go straight to the source people

  101. Cannabis usage leads to cognitive impairment. That statement is as misleading as alcohol usage causes death. If you consume cannabis to extreme, it certainly will have detrimental effects, especially among young still evolving brains. Intoxicating yourself for the majority of your time, with any substance, is unhealthy and detrimental to mental health.

    1. Wrong. It’s a neuroprotectant. It helps with brain health. Whoever taught you about cannabis was biased. If you want facts, you’ll have to unlearn and let go of the false information you’ve learned about cannabis.

  102. Some of the reasons for cannabis use are for the exact effects that are in this study. Sometimes you really do want to stop thinking.

  103. Are they paid to ignore the Number 1 and 2 consumed psychoactive substances , Caffeine and Sugar ?

  104. This is actually written piss-poorly and tells us nothing.

    What do the ‘k’ values represent? Why is there no name for quoted statements?

    Please publish things once you learn how to publish them; some elementary science laboratory classes in a higher academic setting may help.

  105. What are the parameters, did the test subjects have existing conditions (ADD, ADHD, OCD, Depression, Anxiety, Existing cognitive deficiencies, ect.).

    And what does the author mean by after it’s typical effect? How long after was this test conducted?

  106. This is some bullshit. Yes, marijuana is not for everyone but it HAS helped a lot of people and demonizing it doesn’t help anyone. Fuck this article you’re a bunch of pussies and what you wrote is old fashioned and untrue propoganda.

  107. I have been smoking for 40 years.
    I have a master’s degree in engineering, and have never had a car accident. The value in marijuana outweighs the negative affects for me for.

  108. Wow. What an amazing article. It really explained the neural effects of cannabis down to a science. I would have never guessed that acute cannabis intoxication could affect basic cognitive skills. I really appreciate how it exactly detailed how long the effects persisted afterwards, the results of the trials in average cases vs. outliers, and the neural processes that caused the impairment. Someone give these scientists and article writers a raise. They’re truly using their college degrees beyond expectation.

  109. I call BS. The poor methodology and sample bias produce a flawed conclusion. This is certainly an area worth studying, however this a poorly conceived and executed attempt apparently skewed to produce a preconceived result.

  110. This is the stupidest article I’ve ever read. Everyone knows the affects of cannabis use. Now why don’t you write an article comparing and contrasting the use of cannabis to alcohol. No of course not. Then no one would consume alcohol, which is extremely bad for you. Instead you wrote this bs

  111. I’ve used cannabis for PTSD as a way to stop nightmares. Every night before bed for over 30 yrs.
    IMO it will always be safer than alcohol. Maybe add to this the difference in the marijuana from 3 decades ago to the weed smoked now! We used to have naturally grown but now hydroponics & a spray of extra THC are ruining the medicinal uses.

  112. This information has been known since forever by anyone that has used cannabis. It is why medical cannabis patients are counseled about not doing anything while under the influence for 4 hours and being aware of longer term side effects. I wonder why your site fails to compare the effects of cannabis to alcohol, but can only assume it is due to the intent of Political propaganda. You should try watching a Chrrch and Chong Movie. You might learn something.

  113. Interesting article. I have been a heavy marijuana user for the last year or so and I can attest to these symptoms. However I am not sure if I’ve especially experienced them while not under the influence. That said I’ll keep this article in mind.

  114. While ur findings may b legit..I was a cannibus user off & on thruout my life & I have a neurologist disorder.ataxia (epilepsy) Ive taken meds for anxiety depression panic attacks 2 types arthritis fibromyalgia degenerative discs desease..only thing that truly help all conditions glaucoma..without a doubt..was cannibus..with no side even made me more cautious..more I had to stop use & the side effects of meds I’m on I haf to b careful opiods for pain ruins my nerves already have nerve disorder since I was 14 yrs old..I’m 57 now..but as long as I could toke everybody that knew me..thought I was healthy..since I’m on a check now I can’t touch it. & I can honestly say..without my cannibus..I ain’t worth a damn!just some people need it as medicinal..please don’t STOP that use of it! I can’t drink alcohol because it cancels my antiseizure meds

  115. I’m a 74 yo female, having used cannabis since age 23, moderately using for most days of these years. I’m a college grad, single and self sufficient. However, I’ve recognized for a long time that my cognition is reduced, following all descriptions noted in this article, if not even more deficits. All the while, I’ve suspected it was the cannabis use (as opposed to the aging process). After reading, I am convinced I fall into each category at least as moderate, possibly in a higher range. As I have recognized this decline, I have told myself for years that I should stop but I’ve always “loved” a small “buzz”. It definitely is the addiction to this buzz that I continue to use. I guess no turning back the clock now. Thanks for the insight that confirms my suspicions.

  116. I credit the cognitive impairments from my daily use of marijuana for keeping me from killing as many Republicans as possible, and then myself.
    I also have to say that I have solved structural building problems in my head both while stoned outta my mind…accurately and achieving significant cost savings. It’s true I can’t remember what I walked into the shop to get, but I remember other things I needed instead.
    It’ll come to me. It’s floating around in there.

  117. I don’t think they did enough in this study to rule out the effects to be causation over correlation.

  118. This is such BS. Anything to make cannabis to look bad so that Big Pharma can continue to sell their drugs that are addictive and deadly.

  119. This just gives research evidence to common experience.
    All the Cheech and Chong movies were based on these exact effects that were commonly understood by users.
    But, the politicalization of cannabis, has led to cannabis being talked of as harmless and cannabis legalization was used to get young voters to vote.
    Now, we, too late, again see talk of the terrible cost of cannabis use.

  120. More bs manufactured science. This is an opinion field based on adding clientele to the list. It’s self serving science based in lies. Most pshycology/pshycologists are this way. Why don’t you just mandate a shot and call it a vaccine and then make people pay for booster shots every 6 months, or tests and call it a disease or outbreak. No you just lie to further your own pockets. Prohibition much, this is not science just like the Fauci’s of the world. Just follow the money, did you pay the people that were your test subjects, no I think not.

  121. You’re study seems to be as cognitive as one of your pot smokers.

    I’ve seen these effects in already underdeveloped mindsets who further smoke their way into believing everything is all good.

    Yet, alcohol is legal. How does your study compare alcohol vs THC.

  122. Meta analysis? Conducted searches? Not a real study. I find what I want to hear when I search for things too.

  123. Why dont you ever cite by how much? (maybe because your sensationalistic text would fall apart)
    In one study participants who were regular users were compared to people who dont use cannabis. They were asked to remember 15 words. Average rememberance for people who dont use was 9 words and oh lord what a shock for people who do use, an average of horrific 8.5 words. yeah.
    Stop writing with blatant sensationalism.

  124. This article on Cannabis “permanent longterm effects” is a BUNCH OF BULLSHIT!!! I haven’t read a more MISLEADING and EXAGGERATED “story” since Howard Hughes’s propaganda pieces in the 40’s!!!
    What…you couldn’t find a study from Brigham Young University or maybe Oral Roberts School has a “Devils Lettuce Studies” department!! See if they got any GENERATED DATA!!!


  126. 500+ years of well-documented anecdotal Cannabis effects must be wrong — can’t we just re-run this whole shebang without the PR-twist. I think the abstract should really hook the reader by referring to all metrics here as the simple ‘Fun Quotient’

  127. It seems these “findings” are vague. Although, they may have some value and hold to be true to verying degrees, for most users, the negative implications of ‘smoking weed’ are not of a great enough consequence to affect their lives. The ‘amount’ of weed is the best way to maintain a healthy, enjoyable ‘high’. Unlike alcohol, weed does not make you physically sick nor will there be a significant derogatory hangover period following.

    Weed may be about as harmful as caffeine, in general, and can be enjoyed as a part of a healthy lifestyle that seems to appeal to many in many communities.

  128. Do you have a suggestion for how long these deficits may occur following intoxication? It’s rather ambiguous to simply state that something remains in your body following use… That much is apparent. 2 hours after? 4? 12?

  129. Always good to know updated weed research.
    I’m not impressed that the findings here are anything more or less than proof that the effects of THC intake vary by individual ‘intaker’ and over time, such that some tokers indeed have more persistent (temporal in nature) effects than other tokers.
    No additional charge for the extended buzz.
    What’s the ‘problem’ again ?

  130. This study is complete and utter nonsense. I have smoked for 25+ years and me personally these things don’t happen to. I smoked while I was in high school. It helped me focus on my school work.

  131. That’s entirely false especially for those of us with ADHD it makes function like you normies because we are wired at such a higher octane that without it we sound like Biden trying to answer off script questions

  132. I been using marijuana for yrs now your research is not true I’m 58 been smoking sense I was 14yrs old and I have held a job ever since and my driving is great don’t now how you do your research but maybe you need to research people that smoke marijuana and not research the first timers. And my doctor didn’t ever now I smoked weed and cigarettes because marijuana helps heel your body and my lung are clear. So go on with your bogus research because researchers like you are just trying to stop the legalization of marijuana.

  133. “Low to moderate quality” means dubious conclusion at least. I recall a lecturer in medical school who remarked “meta-analysis is to analysis what meta-physics is to physics.”

  134. Marijuana use leads to….uh…uh…wait…I’ve got it. Give me a second….
    What was the question again?

  135. That is ridiculous! I don’t smoke anymore but I do know that I made better decisions and contemplated on each decisions outcome before making it. I could read a book and tell you what I read. Also, I was a much better driver! This is not true.

  136. Has this been peer reviewed? I feel there’s alot missing in this to make it a scientific document. You say what was found but you didn’t clearly explain how you found it. From my view, there are some holes in this.

  137. So is anyone going to mention how YouTube shorts and tiktok and IG are impairing all the same areas highlighted in this thread?

  138. Yes, when you are high on anything, your cognitive skills are impaired. We’ve know this for many years genius, GOOD JOB SKIPPY! When cannabis is used moderately for medical use, cannabis helps out in several ways and it is known to be medically safe and effective for multiple medical conditions. Awesome detective work on letting people know how cannabis can get someone “High”. You deserve a raise!

  139. There are those that have no impairments. Without doing a thorough analysis of each individual case and the behaviors of the individuals before consumption of cannabis how can you generalize the effects? Not trying to be negative just wish for others to consider all variables before drawing conclusions.

  140. Didn’t really need a study to observe the obvious. People that smoke weed always seem slow witted and dull, high or not. That those cognitive changes are permanent is disturbing. Perhaps time to reconsider these legal weed shops on every corner.

  141. Ha, guilty as charged! ?
    So glad to see an actual non-biased weed study with results that actually make sense.

    I would like to know the age groups though, i feel after time you learn how to overcome those effects.

  142. Was this study really necessary? U could have asked a group of smokers and they cud have told u that when they are high…they aren’t trying to learn. They are trying to destress or help with pain. ….do a study on that instead of coming to the conclusion that we smokers already knew…. marijuana doesn’t make u crazy . This study showed that ppl were mild to moderately…high! I really dont respect these kind of research articles…they study what we already know….pot gets u high for a period of time…then u have to smoke again to get…! What a finding. Oh when u smoke ur reaction time isnt as good as it was before u smoked… Who didn’t know this already? What a waste of money for this stupid study to be done.., u guys sure u weren’t smoking a lil mary jane to come up with this dumb idea?!

  143. It’s funny how this is out, but we have 27 different us patents that state the exact opposite

  144. This study is heavily skewed by news, published in “addiction” I wonder what- if anything positive they have to say about cannabis. Would love to know the strain and quality of flower in such a study, testing cognitive abilities such as information retention after a heavy sedative indica SHOULD do this..what happens with motor functions and memory, or focus with an hierloom sativa? too many rope-a-dope contextual phrases such as it “May” do this are just fear mongering indicators, too many variables to be considered scientifically accurate and comes off as a bias study.

  145. Tell that to my three engineering degrees. I’d love to be a test case on that contrived nonsense.

  146. I wonder how accurate this research is without several different contributing variables being accounted for. Im all about statistics and analytical data, but this seems a little contrived and not fully researched. The data seems incomplete and I definitely have questions about your 43,000 participants. Were any on prescription medication previously? What’s there family history?? Alzheimer’s? Dementia? How old are they? How long did they use marijuana? I’m definitely inclined to believe some of the data compiled in this research as temporary side effects, not as inclined for long term. Medical marijuana has countless benefits and the side effects for marijuana are SUBSTANTIALLY less severe and debilitating than Big Pharma. I was able to take myself off of 3 top tier narcotics because of it. My father might possibly have lived had it been legal when he was diagnosed with cancer(my dad couldn’t eat because of the chemo affecting his tastebuds). I feel like this article took MINOR short term side effects of marijuana and introduced the possibility of elongated symptoms as… what? A deterrent? Why? If you listed the POSSIBLE long term effects of marijuana next to long term effects of prescription medication there would be no contest. Marijuana would win- Every. Time. Taking your time to write a repetitive paper on long term effects of marijuana seems like a right wing agenda in this perspective. I feel like I just read something from the 70s titled: Just Say No. What’s the agenda here? Is it purely for science? Is it really?

  147. Come and say that to my face. What were you testing teenage stoners? You should be sued for spreading lies and false information. What is your excuse for being dumb?

  148. “Meta-analysis” meaning they took old debunked papers and slapped their closing remarks together for a new article. The co-author Alexandra is a psychiatrist prescribing a multitude of psychotropic drugs to people seeking “professional” help. Not to mention their pre-existing cultural disdain for cannabis.

  149. I been smoking marijuana daily for 22 years. Missed about 12 days since I’ve started. Cognitively I’ll run circles around you. We can test your theory with a series of IQ test on me at baseline and on the dependent variable. I guarantee I’ll score higher on weed. You’re not accounting for external factors ie. Stress, mania, anxiety…

  150. Well… It’s nice to know that science has proven my thoughts all along! I’ve been talked bad about my conclusions but to see it here is refreshing! I just wish there users and abusers would understand.

  151. This study is slightly inaccurate. I’m one of millions where this does not happen. Like anything, it’s based on your DNA and the receptors in your brain. Furthermore, too much of anything is not good and can cause cognitive response to vary.

  152. Well DUH! Could have saved a ton of money in that research lol
    Song from long ago “I got stoned and I missed it”

  153. So if you are saying that cognitive impairment is caused by the use of canabis? Then are you suggesting to having a label put on it like other pharmaceuticals ie do not use while operating machinery until you understand how this drug may affect you. Would this be the idea you were searching for? Also not everyone whom partakes in canabis is affected in the same way. So honestly this study only shows the ability to partake and be affected. The effects you mentioned also happen when a person is tired or lethargic from lack of sleep. So might I suggest you do some more in depth research and not assume all people are affected the same way by canabis.

  154. This Study is BS. The “Source” of this society for studying addiction also made points to oppress bigger studies like Dr Bruce Alexander’s Rat Park that contradicts everything that people say about addiction today that was based of rats in skinner cages. Why did Vietnam vets do heroin in vietnam, but we didnt have an epidemic of strung out vets after the war? Why doesnt grandma get hooked on wholesome pure morphine after 21 days on it for a hip surgery, but a junkie on the streets gets water down heroine and is hooked in a couple doses? What about gambling addiction? How does that substance work? People need to realize its not impairments involved. Its heavy funded lobbying groups involved. Personally cannabis for my PTSD has greatly improved my cognitive performance. I think way more in a 3 and 4 dimensional thinking than I ever did before as possibly a 2 dimensional thinker. (Source 1 2 3 or 4 dimensional thinking in lit and character building many use as metaphors to describe growth in awareness of thought.) So from my experiences as well as countless others as an activist grabbing signatures and sources for its legalization, I think we need a better group to relay any sources from than them. Anyone want to actually help someone they feel is smoking too much pot even, let alone anything more, learn about Bruce Alexander’s contractions on the way we understand drug addiction as its actually a form of poor coping more so than addiction. Thus is why groups like the society here will correlate with out causation in studies like this to slander how many LIVES this plant saves daily and how many lives it relieves elements of illness from. Keep grasping at straws. Also just for what ifs, there was times my CPTSD was so bad i was smoking 2oz of high grade cannabis per week before I got control and moderated it out more. Tell me how impaired I was where this substance was prohibited then yet I worked daily with law enforcement. I did pretty well having pot in my pocket, performing a job, and more like running for office even. So just maybe we need to loosen up some on this utter propaganda that just seems to attack cannabis rather than any pragmatic information to better understand its use. Lastly not everyone has tried cannabis, so allow me to give the feeling of the ‘high’ people witness that these studies define intoxication by. Every laugh so hard you tear up or had such a great time you have a swimmy headed feeling of bliss that’s completely natural to have? Yes? Thats the high being prolonged rather than a temp effect. It forces this feeling of emotion on you. Its mearly impossible to think negative to create a negative reaction to people. Youre thought out. Youre more aware of factors like good times prior to smoking you were caught in the moment. You think in many angles that without you wouldnt. Never smoked and want to experience this effect well this is for longer term users. New users would easily have a moment of adjustment to gain what most define as a level of tolerance. Prior to this you get the same feelings and during this time most any pot smoker agrees dangers to driving can occur. Post this era of tolerance not so much. Till then you can forget what you were talking about mid sentence and laugh. Why? Not cause you were just nonsense and dumb, youre thinking of how you were leading the sentence in steps ahead of what you were saying and forgot how you were formulating the conversation. It helps relax the thought process so much many need to get used to it at first. Once tolerance has been made and we strive for a realistic form of moderation, you too would laugh at this article in the milestones cannabis has helped your cognitive functions as much as ironic thinks like muscle memory, hand eye coordination, and more. Why, cause youre enjoying the task that helps you do learn these acts, not the cannabis, but its byproduct in relieving emotions and emotional distress in people by its effects. As far as my youth. I started smoking cannabis at 8 years old. Cigarettes at 12 and quit cigarettes at 24. When your abused the streets become family sometimes and we make poor choices. The poor choice i made was cannabis and comes to find out it relieved many elements that was holding me back as a child in distress too. Went from having no friends and not social to being social. I went from being a punching bad to understanding self worth. Those worried about kids lets talk. Cannabinoids are even found in natural breast milk, not formula. Remember that next time you here a gov or hospital rag a mother about breast feeding and remember this point. Smoking is bad regardless, but as a child if I had the edibles, ID probably had a healthier experience than the everlasting and forever failures of prohibition being how i get my supplies as a child. Same as children with any prohibited item. As far as my memories. They have went near photographic with combination of pot and PTSD. While i lack audio ques in long memories, i remember visuals ques and patterns with ease better than most. Prior to smoking when I was younger all prior to puberty smoking pot, I struggled remembering what my mother told my overwhelmed all the time. Today my memory is better than my coworkers and majority peers, my cognitive skills all around are above average. Not anything i blame pot for. I also reveal all this openly and freely as its evidence that contradicts this post and I dont need sponsored or paid to say Cannabis saves lives as well as its saved my own. Get yalls sponsored pay outs else where than supporting something being banned that saved lives.

  155. Alcohol is by far the worst drug, yet so widely accepted and promoted. It can literally change the RNA and DNA which can lead to alcoholism through generations. Nothing good comes from alcohol, shine some light on that!

  156. after smoking marijuana since the age of 16 I went back to college at 50 and graduated with a 4.0 at the top of my class.

  157. Luv how everybody is trying to find something wrong with cannabis but nicotine kills 500000 wolrd wide every year buts it’s fine lol

  158. Bullcrap as a cannabis user I call crap. I’m a college student who gets straight A and have nothing wrong with my brain from using cannabis.

  159. Is this a joke? It reads as if getting stoned leads to getting stoned. I could have told you that for free. I’m intending to be rude I’m just blown away that people felt the need to spend money to find that out.

  160. Sorry, but it’s difficult to put much credence in an article which misses so badly from square one. Think caffeine

  161. Lol no surprise a group that believes every drug is addictive published a lopsided misleading study confirming their own belief. Gtfo here with this clickbait

  162. I have used “cannabis”, on and off, for many decades. Just last year I took a year off of it to see what, if any,, difference I would notice or experience. Besides the hundreds of dollars a saved I have to say that I was able to be a bit more productive but didn’t notice any considerable brain function changes. I feel that anything you consume, even nutritious items, can either be beneficial or detrimental its all about moderation.

  163. No idea what your angle here is.. but I’ve been exposed daily for 45 years and I’m 100% sure you’re all full of shit.
    I’d be a vegetable by now ffs.
    Make more sense.

  164. The same is said for alcohol: cannabis & alcohol should be taken in moderation period. Stop putting scare tactics only on cannabis when alcohol kills.

  165. Wow!! No wonder the world is laughing at us! This type of garbage belongs in the funny papers. Lies and B’s!!!

  166. So you interpreted a collection of studies over time without doing any independent research? What exactly is the purpose of this? It’s obviously going to be prejudiced. I wish I had a job where I could take someone else’s work and call it my own. Decades later.

  167. Guess I’m the exception to the rule? I’ve been smoking since I was 16, when it helped me cope with the abortion I decided to have (a year after my 1st son) & many other stressful experiences I’ve faced. I would’ve excelled in life if the stigma about cannabis use didn’t block my progress after college. At 64 & only stopping for 2 years (while pregnant), I have more sense & better cognitive abilities than most of my peers who don’t smoke. I wish it cold make my knees less painful though ?

  168. How can you be sure of causation? For example can you be sure that a higher incidence of executive dysfunction is because of prolonged cannabis use; or because the individual most likely to be a regular user already has problems with executive function skills? I’d be interested to see more information.

  169. I’ve been using marijuana consistently since I was 12(I’m 30). I have a photographic memory. And the only reason it would take me longer to make a decision on anything is that marijuana allows me to think at a slower and more thorough pace, allowing me to make the best possible decision. Compare these results to those under the influence of alcohol and caffeine.

  170. Duh!

    That’s the whole point of smoking weed. They do call it smoking “dope“. What an unbelievable waste of money this study is.

  171. This article doesn’t include any concrete statistics. I would have especially liked to see some in regard to the relationship between frequency of use and severity of impairments.

  172. BS study, I can point out 3 glaring holes right off the top of my head. Let’s start with the most obvious: THC stays in the system sometimes for as long as 3 months, I know because that’s how long it takes for me to clear my system. So were subjects tested while high and then asked to come back 6 months later after not smoking for those 6 months? Were the tests performed at any other point in the subjects life, so as to get average performance data? Were subjects tested multiple times at all?

    Like I said BS study conducted with psuedo- science, probably by more children who can’t even drink legally than with accredited professionals.

  173. “ANYTHING” That unnaturally impairs normal thought process and reaction time is “POISON”! Anything on the planet that is smoked will kill you if you smoke it enough. Cannabis is “ADDICTIVE DOPE” !
    PERIOD !

  174. A vital bit of info missing here: how long after intoxication do effects last? Are we talking minutes? A day, like a hangover from alcohol? Permanent? If the former two, that’s to be expected and not necessarily a huge concern (though still important). If the latter, that’s vital info.

  175. What is this reefer madness crap? It’s 2022 can we stop trying to come up with stuff like this to discredit the benefits of cannabis. No you’d all rather go get drunk and literally kill braincells. I work doing computer programming for a multinational billion dollar corporation. I smoke everyday before and after work, sativa in the morning indica at night. I’m one of the top performers in my department. Mornings I don’t have my sativa I feel like I can’t focus as easy and lose my train of thought. But you know, drugs are bad mkay. What a joke, everyone involved in this study needs to go down a 5th of jack and come back to me about the “lingering cognitive effects of marijuana use” HAVE YOU GUYS EVER HAD A HANGOVER?

  176. Any psych 101 student should know that claims and terms like “leads to” or “produces” cannot be accurately used to discuss research that is not of true experimental design. It is sad to see this from this website

  177. So no information regarding how permanent these effects are? Is the information listed here new information?

  178. I have been smoking weed for 25 years. Kids shouldn’t do any mind altering chemicals including caffeine or round up or cigarettes or weed. Weed should be legal at age 21 for everyone.

    Everyone should have an alcohol license to buy alcohol and a weed license to buy weed. Get in trouble while on the substance, you lose a license to enjoy it.

  179. This information has been well known for many years, even many decades. But try to tell this to a user.

  180. It’s not the marijuana. It’s the public education causing cognitive deficiencies. Education in the US has been on a steady decline since the creation of the DoE. Let’s all ignore this fact.

  181. Where do they rwally get this information? I will be that not one of the oersons doing this study has ever never gotten high before. I grew up in the early 80’s and can say that i smoked a LOT of marjiuana. A LOT. Sometimes 4 or 5 joints a day. Fir a oeriod of 15 years. However, i went to school an got an associates degree in electronics engineering 10 years after high school and after a 4 year stint in the marine corps. And went back and got a bachelors degree almost 40 yrs out of high school in cimputer drafting and project mgmt. How is that possible in regards to this study?

  182. This is ridiculous. I have a doctorate and every single friend of mine in med school smoked cannabis regularly. Put that in your pipe and smoke it!

  183. So what are sober peoples exuses for thier cognitive issues. I been a heavy weed smoker since 14 now 35, no college degree yet I work where a degree is REQUIRED…. just sayin

    1. The concept is a reduction of various cognitive capabilities.
      If your capability prior to cannabis use was rated a 100, after use the capability is down. It depends what you do as to whether decrease falls below a performance threshold, but the decrease is real.
      Ironically, that you did not grasp that concept might show a threshold reached.

    1. You wanna see something funny? Let’s compare my(30yr smoking) IQ score to YOURS!!! We can even make it interesting and have a little “side bet”! Sad little sheep.

  184. Gonna call BS on that study, probably funded from groups that oppose legalization. I’ve been using my whole life and don’t have those problems, in fact, I got a two year associate degree in seven months while using during studies. Some of the greatest musicians, even Mozart, artists, inventors have admitted to using cannabis, the first personal computer, Apple, was invented while they were using.

  185. The claims in this study are dangerously false!!! if you go in the woods looking for silver goo you will most likely find it . So fucking stupid why don’t you do a study about the fact that cannabis as a whole has been falsely represented for the last 50 years to give gains to a small percentage of this world. In turn giving the insane placebo effect that you fools keep wasting money to exploit!!!

  186. Most if not all of what is claimed in that article is knowingly false. It should be illegal for such claims to be made. This person and their study should be disregarded, if they even truly exist.

  187. I have the same IQ now tha I had in 1980 and I have smoked weed almost everyday since I was 17

  188. Average consumer of news, not a neuroscientist of any kind. My question is, how do you explain Elon Musk? Or any of the other marijuana users that obviously have good decision making skills, memory & function? I’m wondering about the cognitive function of the test subjects had they NOT been users. I know plenty of “stupid” people that smoke weed, & just as many that don’t. In reading the article, I’m pretty sure it said the quality was low to moderate. The quality of the studies they were using. So how is this definitive findings? Based on low to moderate quality studies? Seems like Reefer Madness just won’t die.

  189. Yes, but just like other drugs, there are possible side effects. And are these effects permanent?

  190. How much government funding was used in producing information everyone knows anyway? Not only did someone get to get high for free for this study……they probably got paid for it too!!!

  191. This is stupid. Millions of people have been using cannabis for a long time that are intelligent and successful. Maybe the issue isn’t cannabis causing issues but that often times people who are disinterested in learning or being on point with life happen to enjoy it. Let’s look at how alcohol, the internet, tv, sugar, dairy, and other common things all contribute to issues with memory or cognitive function

  192. This is BS per my experience. My grades were excellent and tests were a breeze when i studied high. Valedictorian was a stoner. The repressed creative side opens high. I can play my instrument, cook, enjoy the color in life. Then i get the munchies and want to zone out or nap. I do know some brain dead stoners but honestky, they drink quite a bit too. Wishing pit were legal here and until then, have none. Pardon typos, etc. My screen disapeared.

    1. Actually I work way better high than I do without. Focus is increased, dexterity is increased, comprehension and reaction is increased in my case.

  193. Lol.I just watched a cardiologist say, “Sugar isn’t the problem, eat all you want.” Some people will say anything…

  194. I’ll take the risks over the numerous side effects of all the man made drugs promoted by legal drug traffickers aka doctors, causing serious issues with our physical and mental health.

  195. A meta review of meta analysis of low to moderate accuracy sounds a whole lot like Reefer Madness trying to slow the legalization.

    1. Exactly what I said before reading all the comments! Then was delighted to see EVERYONE IS CALLING BS! I also referenced Elon Musk. Bet they don’t have an explanation for him!

  196. Were these people actual smokers? I smoke marijuana like cigarettes and I’m the sharpest person in every room I step in. People often ask me what’s my secret… I smoke pot.

  197. I call BS on this research. I’ve been smoking habitually on a daily for the past 25 years and have never had an issue remembering or completing a task or even having issues with staying focused. Just another group of scientists hellbent on trying to make themselves look intelligent because half the nation knows better then there MLB OR MASTERS DEGREES. What’s next pot causes osteoporosis. Idiots

    1. I love reading these comments! Dude, you go! Preach baby, prea….what? Wait… [60 seconds later]…

      See? I been smoking Girl Scout Cookies all night and I ain’t got no impairments!

      That’s the fun part of brain damage! You hardly ever know what your missing! Pot and Porn lead to political apathy! It’s a potent brew. Religion used to keep people in line, but no one really buys it anymore: Too much sexual abuse. But pot and porn work great! Conspiracy theories? No just corporations getting better and better at ruling the polis. It’s easier if people are cognitively impaired. Only the intellectually lame would sign-off on the status quo.

  198. This article reveals nothing about “how” this studies were performed. (I.e. the “Methods” section is two sentences long, and includes no detail.)

    I don’t see any explanation of the control variables listed for any of the experiments.

  199. That’s a pure fiction it’s been established as a neural protectant meaning it protects your neural network not denigrated you liars of disinformation you’re going to pay for that one day…

  200. Okay but quanitively speaking, for how long?
    What is the half life of these residual effects? Are they reversible?
    How can they be reversed?
    Is this shown in the paper?
    Or was this just a boolean hypothesis that didn’t generate any useful models/functions?

  201. Where are the stats? Where are the graphs showing the difference? What does small, moderate, or acute actually mean numbers wise? Science is quantified in numbers, not subject terms.

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