6 ms·

Long-Term Cannabis Use, Cognitive Decline, and the Hippocampus

61 points by mosiuerbarso 4y ago

AlanYx 4y ago
What's most interesting about this article IMHO is that these results were found with "long-term cannabis users" defined as those who use "typically 1-4 times weekly". That seems like relatively casual use.
- varispeed 4y ago
  Author obviously has a conflict of interest. He fails to acknowledge that correlation is not causation and that these studies fail to take into account other variables that could influence the outcomes.
  - austin-cheney 4y ago
    I read the article and did not see anything that would qualify as a conflict. Correlation is not causation only on its face, which is why researchers compare their findings against control groups.
    - varispeed 4y ago
      > a psychiatrist who specializes in addiction medicine. And typically their are missing confounding variables.
  - SamoyedFurFluff 4y ago
    I don’t think you’re using conflict of interest correctly. You’re saying here the author has secondary motives, such as being sponsored by an anti-weed org or something, which they would have to disclose in their own section (as per basic academic standards). You might want to instead if you want to criticize the research say the authors clearly have a personal agenda or bias.
    - edgyquant 4y ago
      This is par for the course. When anyone suggests that weed may not be beneficial to your health people who consume it tend to get very defensive.
    - varispeed 4y ago
      It is common for people working with addiction to demonise drugs, so that they can have stream of scared patients lined up.
      - starkd 4y ago
        I don't think they have any shortage of patients in rehab. There is already a steady stream of them. Rehab counselors are often former addicts just trying to help others live through what they did. It is not exactly a way to get rich.
  - f6v 4y ago
    > correlation is not causation True. But then there’s something that makes you stupid and makes you use cannabis at the same time. This is as bad as just cannabis making you stupid.
    - varispeed 4y ago
      It's the same situation as observing that people who take pain killers have headache, therefore pain killers are causing headaches. This is the level where OP's article is at. It's baffling that people upvote that drivel.
- mckirk 4y ago
  That highly depends on your frame of reference, I suppose. In most of Germany that would be considered fairly 'heavy' use already, whereas most of the West Coast would probably consider that to be rookie numbers.
  - red-iron-pine 4y ago
    I had roommates at UCSC where 1-4 times a day was a minimum. Dude eventually quit cold turkey for a 6+ months. Also quit booze, coffee, and tobacco, dropped out of Uni and hung out at an uncle's cabin in the mountains, real Walden Pond sorta stuff. Did him a world of good, but then he got a job w/ a FAANG and went back to the "smoke two joints" routine again.
- legitster 4y ago
  It's pretty shocking how many people I know who are essentially high 24/7.
- scythe 4y ago
  If you look at the description of the cohorts you'll find that most of the people classified as long-term cannabis users were using cannabis quite a bit more frequently than that (median ~300 days per year). It just happens that the analysis here split people into boolean subgroups rather than trying to quantify a dose-response effect (as the primary outcome; dose-response effects are claimed but not emphasized). I would be most interested in seeing a correlation with sleep disturbances. Some cannabis users claim that they smoke weed to help with sleep disturbances; critics argue to the contrary that persistent cannabis use may cause sleep disturbances. Chronic sleep disturbances are known to correlate with a variety of negative outcomes, and the use of sleep-inducing drugs is known to correlate with a variety of problems as well (including the great boogeyman, all-cause mortality). From my own perspective, I stopped smoking weed last year, but I don't think the overall change has been very noticeable. The use of means can distort perceptions when distributions are not symmetric. Notably, my sleep habits aren't great right now, though I'm working on it.
varispeed 4y ago
Totally not biased load of tripe.
fallingknife 4y ago
I smoked weed constantly in college, and when I stopped, it was like a fog lifted. Its danger was comically exaggerated in the anti-drug propaganda they force fed to kids in the US for so long that a lot of people have a reactionary tendency to assume it's harmless, but they will soon be proven wrong. Still has nothing on America's number 1 hard drug, alcohol, though.
- spoiler 4y ago
  Yeah, I kinda know what you mean by fog. I have a "low key" addiction to weed because I'm a bit emotionally dysregulated and weed helped with that. So, when I'm struggling to cope I sometimes wish I had weed at hand. However the fog thing is real. I noticed it on myself when I stopped too. It did without a doubt help me live a somewhat more normal life than if I hadn't been using it at the time. However eventually as I got better (in general, still got acute episodes), the fog/downside outweighed the benefits. I think it should be studied more as a form of medication. Maybe smaller doses and administered orally, as to avoid the negative side effects associated with smoking or vaping it
- newsclues 4y ago
  I've found it's possible to get high every night, and be clear headed and functional in the morning. A weekend of heavy smoking and edibles can leave me feeling a bit sluggish on Monday. But also refreshed for the rest of the week.
  - deepsquirrelnet 4y ago
    Ditto. I don’t smoke cannabis that is bred to be high in thc, because I prefer a light effect. I use a dry herb vaporizer and don’t have any issues engaging in deep thought work in the morning. My main concern with long term use is dream suppression. So I do take breaks frequently. Also I think it’s not a good for developing brains <25y. Cannabis is great as medicine for colds, flu, aches and a lot of more serious conditions and chronic conditions. In the realm of things that I think the government needs to protect us from, I think cannabis prohibition is completely absurd and insidious. We barely talk about alcohol addiction and god forbid we reckon with prolific Tylenol and NSAID abuse — both of which have acute toxic effects on the body.
Maursault 4y ago
This just in: drugs make you stupid. Alcohol lowers IQ. Watching television lowers IQ. The decline in IQ reported sounds like it's within the margin of error. 10,000 years or more of cannabis use, and it is shocking we are only learning about it now that pot makes you stupid.
User23 4y ago
This is a huge effect size especially in the tails. I wish the article talked about the control groups though. I predict a number of addicts will be triggered by this research. We saw the same effect when we found that even light drinking is measurably harmful. If your first reaction is to get upset and defensive there’s a good chance that you have a problem.
- realce 4y ago
  They'd be triggered by the results, not the research.
- SubiculumCode 4y ago
  and the first to claim that the author is biased.
Felminor 4y ago
What's that? '. Their cognitive decline may have altered employment opportunities for which they were qualified, but they were in no way demented. Yet.' Who writes like that? Also I have insomnia and ADHD and I'm pretty sure weed does help and allowed me to do more not less. Without it I'm super tired already at Thursday. And yes I lived long enough without it and it was like this before my weed use not after.
- mrtranscendence 4y ago
  Interesting. I have ADHD and find that smoking weed makes my symptoms noticeably worse. Depending on how high I get, I find myself largely unable to focus, or even to complete thoughts without becoming distracted. This seems to persist after I'm no longer high -- even many hours after smoking I still find myself less able to stay on task. If you're of the hyperactive type I could possibly see some benefits? As an inattentive and non-hyperactive type it's hard for me to imagine weed helping very much.
  - starkd 4y ago
    I find the same thing. Cannabis just makes me lose my train of thought within 5 seconds. It is very irritating. The one thing I found to help the most is excercise. Even moderate daily walking, but the more you do it, the more benefits you get. There are actually endorphins released that mimic a high the natural way.
  - Felminor 4y ago
    I'm very restless normally. Enough weed and I'm not keeping myself awake. But I only eat a cookie before bed
- gameman144 4y ago
  I have shaky hands, and a shot of alcohol is one of the recommended ways to treat them. This doesn't mean that alcohol has no downsides though. Acknowledging that something has negative long term effects doesn't mean that you have to stop using it, it just means that you should weigh those effects into your mental cost-benefit analysis.
Clent 4y ago
This is not a primary source of anything related to psychology. This site is article marketing for people in the mental health field. The primary motivation of the author's is to self promotion.
- troydavis 4y ago
  Here's the full text of the paper it's covering (cited as footnote 4): "Long-term Cannabis Users Show Lower Cognitive Reserves and Smaller Hippocampal Volume in Midlife": https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9426660/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9426660/
- harveywi 4y ago
  You might say that article is, in many ways, a puff piece.
  - rocketbop 4y ago
    Maybe, but there’s no smoke without fire.
    - LeSaucy 4y ago
      It can be difficult to weed out the useless information on the subject.
      - dgeiser13 4y ago
        I find that to be a chronic issue.
AnEro 4y ago
I also wonder what their lifestyles are in general, and if it would have an effect. I feel like weed puts my brain into autopilot to a degree and makes me 'okay' with w/e I am doing. So recreational usage I could see making you 'dumber' cause weed lets you feel okay doing nothing and doing nothing is a good way to be dumber My anecdotal opinion for someone that smokes a lot compared to their long-term cannabis users, maybe once or twice a night vs 1 to 4 times weekly. I'm late twenties have been smoking since my early twenties, obsessed with brain optimization and min maxing performance etc. I feel like I've gotten smarter in some areas and dumber in others, which lines up with how weed affects the reward circuits of the brain imho. So I've been using it as a reward for doing stuff I otherwise would be uncomfortable with trying, like a new project or new hobbies; anything worth doing is worth doing poorly. So I think it has helped me get smarter programming and developing intuition on some areas, but since I have avoided writing like the plague it's gotten terrible to be honest. Personally it feels like it just tunnels you in further to what ever you are doing, and possibly makes it harder to stop doing it even not high
- runlaszlorun 4y ago
  > anything worth doing is worth doing poorly Ha! That’s great line.
- starkd 4y ago
  Physical excercise can give you many of those benefits too. A good strenuous workout or run will give you a high without any of the harms.
  - AnEro 4y ago
    That's why I also lift and do jogs! That's why I'm interested in the lifestyle peace because I have a pretty healthy lifestyle outside of smoking weed. I think I could be doing better micro nutrient wise and get a better omega and mushroom stack rather than w/e veggies are on sale lol
dankai 4y ago
Look at the sample sizes and the demographics (https://imgur.com/a/LG5vVMF https://imgur.com/a/LG5vVMF) of the groups the study (https://moffittcaspi.trinity.duke.edu/sites/moffittcaspi.trinity.duke.edu/files/publication-uploads/Knodt%20et%20al.%202022.pdf https://moffittcaspi.trinity.duke.edu/sites/moffittcaspi.tri...) compares. Also look at the publication bias of the first author (https://scholar.google.com/citations?view_op=list_works&hl=en&hl=en&user=S82Iu9oAAAAJ&sortby=pubdate https://scholar.google.com/citations?view_op=list_works&hl=e...).
- deleted 4y ago
  [deleted]
- SubiculumCode 4y ago
  if you mean the very small mean iq difference at baseline, that is hardly a significant concern, here especially in a longitudinal design. As far as publication bias, do you mean expert in his/her field?
  - deleted 4y ago
    [deleted]
jamal-kumar 4y ago
This is pretty important kind of research. Tons of people are using this stuff medically and while it's obviously a better solution for pain management than long-term use of things that can kill you if they're suddenly unavailable, like opiates, we should still be highly aware of mitigating whatever harms could come from the widely used alternatives. It would also be more interesting to see harm in aspects of things like hippocampal density compared to pain medication than compared to regular alcohol or other recreational substance use. I kind of feel it's unlikely at this point but it could just turn out that people who are prone to losing IQ points faster like to consume more cannabis as well and it's not as much of a causative agent. I would imagine the first thing I want after getting smacked in the head by someone if this was something I did professionally is something to take the pain away. This study could also just be a crock of shit like some others are saying but I don't really feel qualified to judge that. The only thing that can truly tell with these kinds of studies is another 30 years of data.
- edgyquant 4y ago
  Lots of people use it recreationally with the belief it’s not bad for you at all. This kind of research will help to show them that’s not the case.
  - whalesalad 4y ago
    Everything in moderation :)
  - somehnguy 4y ago
    I don't know if it will really make any difference at all. Many people consume alcohol regularly and we already know that it's bad for you. I think most people are willing to make tradeoffs, especially when in moderation the negatives aren't really that big.
  - jamal-kumar 4y ago
    I doubt most recreational users are using it at anywhere near the same strength or with the same frequency, however. We're talking the difference between 2 and 200 milligram doses of THC here in terms of how it affects people on these levels. One comes in a soda at the store down the street from me. The other you can't get like that and might send your average recreational user to the hospital with a panic attack. I'm wondering also if one of the big factors here is oxygen deprivation. These sound kind of like the same kind of numbers of cognitive decline that you see in air pollution, maybe just generally clogging your lungs with smoke could be comparable.
deleted 4y ago
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_fat_santa 4y ago
My issue with this study is they based it around IQ points. I feel like IQ is a very bad measure of cognitive ability outside of determining if someone is competent of not. And the fact that it only went down by a mean of 5.5, I feel like that small of a decline could be attributed to someone just having a bad day or being a little groggy when they took the IQ test. Had the measured brain waves or brain activity it would be one thing, but I feel like an IQ test is just not satisfactory for a study like this.
- rcme 4y ago
  5.5 is a massive decline in IQ.
- dash2 4y ago
  Have you got any reason to think IQ is a bad measure of cognitive ability? And what makes you think 5.5 points is small? The average is 100 and a typical standard deviation is about 15; one third of a standard deviation looks pretty big to me.
- troydavis 4y ago
  > And the fact that it only went down by a mean of 5.5, I feel like that small of a decline could be attributed to someone just having a bad day or being a little groggy when they took the IQ test. How does your theory explain that the results were particular to certain sub-groups? That is, the 5 point decline was only associated with long-term cannabis users. (Is your theory that long-term cannabis users are more likely to "have a bad day or be a little groggy"? That would explain the sub-group difference, but it seems pretty similar to the author's results.)
troydavis 4y ago
Here's the actual paper. Long-term Cannabis Users Show Lower Cognitive Reserves and Smaller Hippocampal Volume in Midlife: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9426660/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9426660/ From the abstract: > We tested the hypotheses that long-term cannabis use is associated with cognitive deficits and smaller hippocampal volume in midlife, which is important because midlife cognitive deficits and smaller hippocampal volume are risk factors for dementia. > Participants are members of a representative cohort of 1,037 individuals born in Dunedin, New Zealand in 1972–73 and followed to age 45 years, with 94% retention. Cannabis use and dependence were assessed at ages 18, 21, 26, 32, 38 and 45 years. IQ was assessed at ages 7, 9, 11, and 45 years. Specific neuropsychological functions and hippocampal volume were assessed at age 45 years. > Long-term cannabis users showed IQ decline from childhood to midlife (mean=−5.5 IQ points), poorer learning and processing speed relative to their childhood IQ, and informant-reported memory and attention problems. These deficits were specific to long-term cannabis users because they were either not present or smaller among long-term tobacco users, long-term alcohol users, midlife recreational cannabis users, and cannabis quitters. Cognitive deficits among long-term cannabis users could not be explained by persistent tobacco, alcohol, or other illicit drug use; childhood SES; low childhood self-control; or family history of substance dependence. Long-term cannabis users showed smaller hippocampal volume, but smaller hippocampal volume did not statistically mediate cannabis-related cognitive deficits.
- SamoyedFurFluff 4y ago
  This associative effect is interesting in that there’s not a causal proven relationship albeit many common alternatives have been ruled out. It could very well be the kind of people who partake in weed were already predisposed to losing iq and developing dementia risk factors for some other abstract reason, and we can use weed smoking as a signal of something else being wrong. Fascinating stuff tho
  - iLoveOncall 4y ago
    People will really try anything to make it seem like Cannabis is perfectly harmless even in the face of cold hard evidence, it's laughable.
legitster 4y ago
I think there's a ton of self deception when it comes to marijuana use. I mean, look with your own eyes and you can clearly see lots of long-term negative effects on users. The studies are only proving what we all really already know. The same thing was true for cigarettes - even before all of the major studies came out lots of people were able to put together the obvious connection between smoking and lung problems.
- iLoveOncall 4y ago
  > I think there's a ton of self deception when it comes to marijuana use. Indeed, as is evidenced by the many comments in this very post claiming the study is bullshit or there's no proof of causality, or whatever else they can come up with.
- kilgnad 4y ago
  Before legalization in many states, even on HN even the suggestion that cannabis was unhealthy could get you voted down. People refused to believe it. Now that it's legal peoples' objectives have shifted and it's now ok to talk about it. It's a literal example of the stupidity in human psychology. People don't use logic to make conclusions about the world, they use logic to justify their conclusions so they can fulfill their objectives. Very hard to find a person who does cannabis on a daily basis and is also fully on board with the fact that cannabis causes cognitive decline.
  - legitster 4y ago
    *Very hard to find a young person. But you find enough people after 10-15 years of using who will tell you they have noticed some effects. I think it's important to point out that marijuana is certainly less dangerous than alcohol and cigarettes. But it's weird how people try to argue that there shouldn't be any sort of moderation when it comes to weed. Like, even alcoholics won't argue that they shouldn't be drunk all of the time.
    - clbrmbr 4y ago
      The longer duration and fat solubility of canabinoids makes the alcohol comparison difficult. Many people have a glass of red wine with dinner daily, and are not drunk in the daytime, but even very light cannabis consumption nightly seems to result in a permanent low-level stonnedness.
bowsamic 4y ago
There is such a taboo around discussing this that even if you present a lot of people with an extensive meta-analysis showing that there are negative effects people will totally brush it away and call it BS. It seems we have swung way too far in the opposite direction from "weed is really bad and makes you crazy and paranoid" to "weed is totally fine". Naturally the truth is somewhere in between, though so many people seem totally sure it's the latter
m0llusk 4y ago
It might be interesting to give this more context. Does five points of IQ loss in later life actually change outcomes? And what about the rest? In my experience older cannabis users tend to be more centered, pleasant, easygoing, and are better at retaining their social support networks over long periods. My cannabis use has made my life tolerable, so if there really is a loss in IQ then that might not be such a bad price to pay. Comparing my work history with others my age it really isn't clear that my long term regular cannabis use has made any negative change that isn't visible in others. It seems like these studies are mostly about confirming bias. People who are judgemental and don't like cannabis can confirm that cannabis users are bad and slow and degraded and so on. But we are still here we need to share the world somehow so it might make sense to think about balance and trade offs rather than only ever keeping the emphasis on no, no, no, you might degrade some of your capacities.
- Llamamoe 4y ago
  This isn't standalone "five points of IQ loss", this is "brain volume loss culminating in five points of IQ loss among others". 12% hippocampal volume loss is half of what happens in Alzheimer's, it's nothing to scoff at. Does this imply that cannabis is never worth using and we should "protect" people from it? Probably not, but it's sorely needed in light of the "weed is harmless and a medicine for many" narrative that's getting blasted everywhere.
thefz 4y ago
Anecdote time: A couple of late 30 to early 40 year old friends smoke constantly since the '20s. And I mean every day, multiple joints. They claim their life is normal, I claim that... it shows somehow. From senseless paranoia to being reclusive, and sometimes being very late/slow in grokking things, they are very different from the rest. Even from casual, weekend smokers. I think that you can't expect to smoke 5 to 8 joints every day and lead a normal life past your '20s.
yehosef 4y ago
I think that part of the suspicion of research like this comes from years of complete lies about the dangers of cannabis. The fact that is still classified as a schedule-1 drug even though we know that it's nowhere near as dangerous as it was claimed. It's also important to note what affect cannabis has on the pharma-industries. It's a "weed" that can help cure a huge variety of serious issues with far less cost, side-effects and risks than prescription drugs. Given the influence of the big-pharm on medical publications and research, I assume some people will be suspicious of any research which says anything bad about something that might affect their bottom line. I'm not saying these arguments are valid for this article, just explaining another angle why some people might be suspicious.

61 points by mosiuerbarso 4y ago

What's most interesting about this article IMHO is that these results were found with "long-term cannabis users" defined as those who use "typically 1-4 times weekly". That seems like relatively casual use.

varispeed 4y ago
Author obviously has a conflict of interest. He fails to acknowledge that correlation is not causation and that these studies fail to take into account other variables that could influence the outcomes.
- austin-cheney 4y ago
  I read the article and did not see anything that would qualify as a conflict. Correlation is not causation only on its face, which is why researchers compare their findings against control groups.
  - varispeed 4y ago
    > a psychiatrist who specializes in addiction medicine. And typically their are missing confounding variables.
- SamoyedFurFluff 4y ago
  I don’t think you’re using conflict of interest correctly. You’re saying here the author has secondary motives, such as being sponsored by an anti-weed org or something, which they would have to disclose in their own section (as per basic academic standards). You might want to instead if you want to criticize the research say the authors clearly have a personal agenda or bias.
  - edgyquant 4y ago
    This is par for the course. When anyone suggests that weed may not be beneficial to your health people who consume it tend to get very defensive.
  - varispeed 4y ago
    It is common for people working with addiction to demonise drugs, so that they can have stream of scared patients lined up.
    - starkd 4y ago
      I don't think they have any shortage of patients in rehab. There is already a steady stream of them. Rehab counselors are often former addicts just trying to help others live through what they did. It is not exactly a way to get rich.
- f6v 4y ago
  > correlation is not causation True. But then there’s something that makes you stupid and makes you use cannabis at the same time. This is as bad as just cannabis making you stupid.
  - varispeed 4y ago
    It's the same situation as observing that people who take pain killers have headache, therefore pain killers are causing headaches. This is the level where OP's article is at. It's baffling that people upvote that drivel.
mckirk 4y ago
That highly depends on your frame of reference, I suppose. In most of Germany that would be considered fairly 'heavy' use already, whereas most of the West Coast would probably consider that to be rookie numbers.
- red-iron-pine 4y ago
  I had roommates at UCSC where 1-4 times a day was a minimum. Dude eventually quit cold turkey for a 6+ months. Also quit booze, coffee, and tobacco, dropped out of Uni and hung out at an uncle's cabin in the mountains, real Walden Pond sorta stuff. Did him a world of good, but then he got a job w/ a FAANG and went back to the "smoke two joints" routine again.
legitster 4y ago
It's pretty shocking how many people I know who are essentially high 24/7.
scythe 4y ago
If you look at the description of the cohorts you'll find that most of the people classified as long-term cannabis users were using cannabis quite a bit more frequently than that (median ~300 days per year). It just happens that the analysis here split people into boolean subgroups rather than trying to quantify a dose-response effect (as the primary outcome; dose-response effects are claimed but not emphasized). I would be most interested in seeing a correlation with sleep disturbances. Some cannabis users claim that they smoke weed to help with sleep disturbances; critics argue to the contrary that persistent cannabis use may cause sleep disturbances. Chronic sleep disturbances are known to correlate with a variety of negative outcomes, and the use of sleep-inducing drugs is known to correlate with a variety of problems as well (including the great boogeyman, all-cause mortality). From my own perspective, I stopped smoking weed last year, but I don't think the overall change has been very noticeable. The use of means can distort perceptions when distributions are not symmetric. Notably, my sleep habits aren't great right now, though I'm working on it.

varispeed 4y ago

Totally not biased load of tripe.

fallingknife 4y ago

I smoked weed constantly in college, and when I stopped, it was like a fog lifted. Its danger was comically exaggerated in the anti-drug propaganda they force fed to kids in the US for so long that a lot of people have a reactionary tendency to assume it's harmless, but they will soon be proven wrong. Still has nothing on America's number 1 hard drug, alcohol, though.

spoiler 4y ago
Yeah, I kinda know what you mean by fog. I have a "low key" addiction to weed because I'm a bit emotionally dysregulated and weed helped with that. So, when I'm struggling to cope I sometimes wish I had weed at hand. However the fog thing is real. I noticed it on myself when I stopped too. It did without a doubt help me live a somewhat more normal life than if I hadn't been using it at the time. However eventually as I got better (in general, still got acute episodes), the fog/downside outweighed the benefits. I think it should be studied more as a form of medication. Maybe smaller doses and administered orally, as to avoid the negative side effects associated with smoking or vaping it
newsclues 4y ago
I've found it's possible to get high every night, and be clear headed and functional in the morning. A weekend of heavy smoking and edibles can leave me feeling a bit sluggish on Monday. But also refreshed for the rest of the week.
- deepsquirrelnet 4y ago
  Ditto. I don’t smoke cannabis that is bred to be high in thc, because I prefer a light effect. I use a dry herb vaporizer and don’t have any issues engaging in deep thought work in the morning. My main concern with long term use is dream suppression. So I do take breaks frequently. Also I think it’s not a good for developing brains <25y. Cannabis is great as medicine for colds, flu, aches and a lot of more serious conditions and chronic conditions. In the realm of things that I think the government needs to protect us from, I think cannabis prohibition is completely absurd and insidious. We barely talk about alcohol addiction and god forbid we reckon with prolific Tylenol and NSAID abuse — both of which have acute toxic effects on the body.

Maursault 4y ago

This just in: drugs make you stupid. Alcohol lowers IQ. Watching television lowers IQ. The decline in IQ reported sounds like it's within the margin of error. 10,000 years or more of cannabis use, and it is shocking we are only learning about it now that pot makes you stupid.

User23 4y ago

This is a huge effect size especially in the tails. I wish the article talked about the control groups though. I predict a number of addicts will be triggered by this research. We saw the same effect when we found that even light drinking is measurably harmful. If your first reaction is to get upset and defensive there’s a good chance that you have a problem.

realce 4y ago
They'd be triggered by the results, not the research.
SubiculumCode 4y ago
and the first to claim that the author is biased.

Felminor 4y ago

What's that? '. Their cognitive decline may have altered employment opportunities for which they were qualified, but they were in no way demented. Yet.' Who writes like that? Also I have insomnia and ADHD and I'm pretty sure weed does help and allowed me to do more not less. Without it I'm super tired already at Thursday. And yes I lived long enough without it and it was like this before my weed use not after.

mrtranscendence 4y ago
Interesting. I have ADHD and find that smoking weed makes my symptoms noticeably worse. Depending on how high I get, I find myself largely unable to focus, or even to complete thoughts without becoming distracted. This seems to persist after I'm no longer high -- even many hours after smoking I still find myself less able to stay on task. If you're of the hyperactive type I could possibly see some benefits? As an inattentive and non-hyperactive type it's hard for me to imagine weed helping very much.
- starkd 4y ago
  I find the same thing. Cannabis just makes me lose my train of thought within 5 seconds. It is very irritating. The one thing I found to help the most is excercise. Even moderate daily walking, but the more you do it, the more benefits you get. There are actually endorphins released that mimic a high the natural way.
- Felminor 4y ago
  I'm very restless normally. Enough weed and I'm not keeping myself awake. But I only eat a cookie before bed
gameman144 4y ago
I have shaky hands, and a shot of alcohol is one of the recommended ways to treat them. This doesn't mean that alcohol has no downsides though. Acknowledging that something has negative long term effects doesn't mean that you have to stop using it, it just means that you should weigh those effects into your mental cost-benefit analysis.

Clent 4y ago

This is not a primary source of anything related to psychology. This site is article marketing for people in the mental health field. The primary motivation of the author's is to self promotion.

troydavis 4y ago
Here's the full text of the paper it's covering (cited as footnote 4): "Long-term Cannabis Users Show Lower Cognitive Reserves and Smaller Hippocampal Volume in Midlife": https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9426660/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9426660/
harveywi 4y ago
You might say that article is, in many ways, a puff piece.
- rocketbop 4y ago
  Maybe, but there’s no smoke without fire.
  - LeSaucy 4y ago
    It can be difficult to weed out the useless information on the subject.
    - dgeiser13 4y ago
      I find that to be a chronic issue.

AnEro 4y ago

I also wonder what their lifestyles are in general, and if it would have an effect. I feel like weed puts my brain into autopilot to a degree and makes me 'okay' with w/e I am doing. So recreational usage I could see making you 'dumber' cause weed lets you feel okay doing nothing and doing nothing is a good way to be dumber My anecdotal opinion for someone that smokes a lot compared to their long-term cannabis users, maybe once or twice a night vs 1 to 4 times weekly. I'm late twenties have been smoking since my early twenties, obsessed with brain optimization and min maxing performance etc. I feel like I've gotten smarter in some areas and dumber in others, which lines up with how weed affects the reward circuits of the brain imho. So I've been using it as a reward for doing stuff I otherwise would be uncomfortable with trying, like a new project or new hobbies; anything worth doing is worth doing poorly. So I think it has helped me get smarter programming and developing intuition on some areas, but since I have avoided writing like the plague it's gotten terrible to be honest. Personally it feels like it just tunnels you in further to what ever you are doing, and possibly makes it harder to stop doing it even not high

runlaszlorun 4y ago
> anything worth doing is worth doing poorly Ha! That’s great line.
starkd 4y ago
Physical excercise can give you many of those benefits too. A good strenuous workout or run will give you a high without any of the harms.
- AnEro 4y ago
  That's why I also lift and do jogs! That's why I'm interested in the lifestyle peace because I have a pretty healthy lifestyle outside of smoking weed. I think I could be doing better micro nutrient wise and get a better omega and mushroom stack rather than w/e veggies are on sale lol

dankai 4y ago

Look at the sample sizes and the demographics (https://imgur.com/a/LG5vVMF https://imgur.com/a/LG5vVMF) of the groups the study (https://moffittcaspi.trinity.duke.edu/sites/moffittcaspi.trinity.duke.edu/files/publication-uploads/Knodt%20et%20al.%202022.pdf https://moffittcaspi.trinity.duke.edu/sites/moffittcaspi.tri...) compares. Also look at the publication bias of the first author (https://scholar.google.com/citations?view_op=list_works&hl=en&hl=en&user=S82Iu9oAAAAJ&sortby=pubdate https://scholar.google.com/citations?view_op=list_works&hl=e...).

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SubiculumCode 4y ago
if you mean the very small mean iq difference at baseline, that is hardly a significant concern, here especially in a longitudinal design. As far as publication bias, do you mean expert in his/her field?
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jamal-kumar 4y ago

This is pretty important kind of research. Tons of people are using this stuff medically and while it's obviously a better solution for pain management than long-term use of things that can kill you if they're suddenly unavailable, like opiates, we should still be highly aware of mitigating whatever harms could come from the widely used alternatives. It would also be more interesting to see harm in aspects of things like hippocampal density compared to pain medication than compared to regular alcohol or other recreational substance use. I kind of feel it's unlikely at this point but it could just turn out that people who are prone to losing IQ points faster like to consume more cannabis as well and it's not as much of a causative agent. I would imagine the first thing I want after getting smacked in the head by someone if this was something I did professionally is something to take the pain away. This study could also just be a crock of shit like some others are saying but I don't really feel qualified to judge that. The only thing that can truly tell with these kinds of studies is another 30 years of data.

edgyquant 4y ago
Lots of people use it recreationally with the belief it’s not bad for you at all. This kind of research will help to show them that’s not the case.
- whalesalad 4y ago
  Everything in moderation :)
- somehnguy 4y ago
  I don't know if it will really make any difference at all. Many people consume alcohol regularly and we already know that it's bad for you. I think most people are willing to make tradeoffs, especially when in moderation the negatives aren't really that big.
- jamal-kumar 4y ago
  I doubt most recreational users are using it at anywhere near the same strength or with the same frequency, however. We're talking the difference between 2 and 200 milligram doses of THC here in terms of how it affects people on these levels. One comes in a soda at the store down the street from me. The other you can't get like that and might send your average recreational user to the hospital with a panic attack. I'm wondering also if one of the big factors here is oxygen deprivation. These sound kind of like the same kind of numbers of cognitive decline that you see in air pollution, maybe just generally clogging your lungs with smoke could be comparable.

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_fat_santa 4y ago

My issue with this study is they based it around IQ points. I feel like IQ is a very bad measure of cognitive ability outside of determining if someone is competent of not. And the fact that it only went down by a mean of 5.5, I feel like that small of a decline could be attributed to someone just having a bad day or being a little groggy when they took the IQ test. Had the measured brain waves or brain activity it would be one thing, but I feel like an IQ test is just not satisfactory for a study like this.

rcme 4y ago
5.5 is a massive decline in IQ.
dash2 4y ago
Have you got any reason to think IQ is a bad measure of cognitive ability? And what makes you think 5.5 points is small? The average is 100 and a typical standard deviation is about 15; one third of a standard deviation looks pretty big to me.
troydavis 4y ago
> And the fact that it only went down by a mean of 5.5, I feel like that small of a decline could be attributed to someone just having a bad day or being a little groggy when they took the IQ test. How does your theory explain that the results were particular to certain sub-groups? That is, the 5 point decline was only associated with long-term cannabis users. (Is your theory that long-term cannabis users are more likely to "have a bad day or be a little groggy"? That would explain the sub-group difference, but it seems pretty similar to the author's results.)

troydavis 4y ago

Here's the actual paper. Long-term Cannabis Users Show Lower Cognitive Reserves and Smaller Hippocampal Volume in Midlife: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9426660/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9426660/ From the abstract: > We tested the hypotheses that long-term cannabis use is associated with cognitive deficits and smaller hippocampal volume in midlife, which is important because midlife cognitive deficits and smaller hippocampal volume are risk factors for dementia. > Participants are members of a representative cohort of 1,037 individuals born in Dunedin, New Zealand in 1972–73 and followed to age 45 years, with 94% retention. Cannabis use and dependence were assessed at ages 18, 21, 26, 32, 38 and 45 years. IQ was assessed at ages 7, 9, 11, and 45 years. Specific neuropsychological functions and hippocampal volume were assessed at age 45 years. > Long-term cannabis users showed IQ decline from childhood to midlife (mean=−5.5 IQ points), poorer learning and processing speed relative to their childhood IQ, and informant-reported memory and attention problems. These deficits were specific to long-term cannabis users because they were either not present or smaller among long-term tobacco users, long-term alcohol users, midlife recreational cannabis users, and cannabis quitters. Cognitive deficits among long-term cannabis users could not be explained by persistent tobacco, alcohol, or other illicit drug use; childhood SES; low childhood self-control; or family history of substance dependence. Long-term cannabis users showed smaller hippocampal volume, but smaller hippocampal volume did not statistically mediate cannabis-related cognitive deficits.

SamoyedFurFluff 4y ago
This associative effect is interesting in that there’s not a causal proven relationship albeit many common alternatives have been ruled out. It could very well be the kind of people who partake in weed were already predisposed to losing iq and developing dementia risk factors for some other abstract reason, and we can use weed smoking as a signal of something else being wrong. Fascinating stuff tho
- iLoveOncall 4y ago
  People will really try anything to make it seem like Cannabis is perfectly harmless even in the face of cold hard evidence, it's laughable.

legitster 4y ago

I think there's a ton of self deception when it comes to marijuana use. I mean, look with your own eyes and you can clearly see lots of long-term negative effects on users. The studies are only proving what we all really already know. The same thing was true for cigarettes - even before all of the major studies came out lots of people were able to put together the obvious connection between smoking and lung problems.

iLoveOncall 4y ago
> I think there's a ton of self deception when it comes to marijuana use. Indeed, as is evidenced by the many comments in this very post claiming the study is bullshit or there's no proof of causality, or whatever else they can come up with.
kilgnad 4y ago
Before legalization in many states, even on HN even the suggestion that cannabis was unhealthy could get you voted down. People refused to believe it. Now that it's legal peoples' objectives have shifted and it's now ok to talk about it. It's a literal example of the stupidity in human psychology. People don't use logic to make conclusions about the world, they use logic to justify their conclusions so they can fulfill their objectives. Very hard to find a person who does cannabis on a daily basis and is also fully on board with the fact that cannabis causes cognitive decline.
- legitster 4y ago
  *Very hard to find a young person. But you find enough people after 10-15 years of using who will tell you they have noticed some effects. I think it's important to point out that marijuana is certainly less dangerous than alcohol and cigarettes. But it's weird how people try to argue that there shouldn't be any sort of moderation when it comes to weed. Like, even alcoholics won't argue that they shouldn't be drunk all of the time.
  - clbrmbr 4y ago
    The longer duration and fat solubility of canabinoids makes the alcohol comparison difficult. Many people have a glass of red wine with dinner daily, and are not drunk in the daytime, but even very light cannabis consumption nightly seems to result in a permanent low-level stonnedness.

bowsamic 4y ago

There is such a taboo around discussing this that even if you present a lot of people with an extensive meta-analysis showing that there are negative effects people will totally brush it away and call it BS. It seems we have swung way too far in the opposite direction from "weed is really bad and makes you crazy and paranoid" to "weed is totally fine". Naturally the truth is somewhere in between, though so many people seem totally sure it's the latter

m0llusk 4y ago

It might be interesting to give this more context. Does five points of IQ loss in later life actually change outcomes? And what about the rest? In my experience older cannabis users tend to be more centered, pleasant, easygoing, and are better at retaining their social support networks over long periods. My cannabis use has made my life tolerable, so if there really is a loss in IQ then that might not be such a bad price to pay. Comparing my work history with others my age it really isn't clear that my long term regular cannabis use has made any negative change that isn't visible in others. It seems like these studies are mostly about confirming bias. People who are judgemental and don't like cannabis can confirm that cannabis users are bad and slow and degraded and so on. But we are still here we need to share the world somehow so it might make sense to think about balance and trade offs rather than only ever keeping the emphasis on no, no, no, you might degrade some of your capacities.

Llamamoe 4y ago
This isn't standalone "five points of IQ loss", this is "brain volume loss culminating in five points of IQ loss among others". 12% hippocampal volume loss is half of what happens in Alzheimer's, it's nothing to scoff at. Does this imply that cannabis is never worth using and we should "protect" people from it? Probably not, but it's sorely needed in light of the "weed is harmless and a medicine for many" narrative that's getting blasted everywhere.

thefz 4y ago

Anecdote time: A couple of late 30 to early 40 year old friends smoke constantly since the '20s. And I mean every day, multiple joints. They claim their life is normal, I claim that... it shows somehow. From senseless paranoia to being reclusive, and sometimes being very late/slow in grokking things, they are very different from the rest. Even from casual, weekend smokers. I think that you can't expect to smoke 5 to 8 joints every day and lead a normal life past your '20s.

yehosef 4y ago

I think that part of the suspicion of research like this comes from years of complete lies about the dangers of cannabis. The fact that is still classified as a schedule-1 drug even though we know that it's nowhere near as dangerous as it was claimed. It's also important to note what affect cannabis has on the pharma-industries. It's a "weed" that can help cure a huge variety of serious issues with far less cost, side-effects and risks than prescription drugs. Given the influence of the big-pharm on medical publications and research, I assume some people will be suspicious of any research which says anything bad about something that might affect their bottom line. I'm not saying these arguments are valid for this article, just explaining another angle why some people might be suspicious.