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.
Fascinating stuff tho
The correlation between IQ and general intelligence is one of the more reproducible results in psychology. Is there a different usage of IQ that you're doubting, or are you doubting that correlation itself?
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.
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.
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.
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.
The only thing that can truly tell with these kinds of studies is another 30 years of data.
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.
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.
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.
You might want to instead if you want to criticize the research say the authors clearly have a personal agenda or bias.
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.
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.
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.
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
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.
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.
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.
Enough weed and I'm not keeping myself awake.
But I only eat a cookie before bed
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.
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.
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.
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.
This site is article marketing for people in the mental health field.
The primary motivation of the author's is to self promotion.
"Long-term Cannabis Users Show Lower Cognitive Reserves and Smaller Hippocampal Volume in Midlife": https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9426660/
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
Ha! That’s great line.
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.
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.
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.
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.)
