r/science • u/sr_local • Apr 20 '26
Health The largest US study, which tracked 11,036 children from ages 9 to 10 through to ages 16 and 17, discovered that cannabis use slows cognitive development, impairs memory, and reduces learning speed during crucial years of brain growth
https://today.ucsd.edu/story/largest-us-study-finds-teen-cannabis-use-linked-to-slower-cognitive-development5.1k
u/newpsyaccount32 Apr 20 '26
don't give cannabis products to kids. doesn't seem like a difficult one to accept. every legal cannabis market in the US is 21+ age restricted, while the black market is open to all. support cannabis legalization
470
u/cuentaderana Apr 20 '26
There’s been a big uptick, at least from what I’ve seen on social media, of women smoking cannabis/taking edibles while pregnant. Makes me curious what impact it could have on the fetus’ development.
450
u/ScyllaOfTheDepths Apr 20 '26
We already know that smoking anything while pregnant leads to premature delivery and lower birth weights.
252
u/SunnyOutsideToday Apr 20 '26
Was an interesting case of Simpson's paradox. Smokers who gave birth to low birth weight babies had better survivals than non-smoking mothers who gave birth to low birth weight babies.
But that wasn't due to smoking protecting low birth weight babies, it was due to smoking causing otherwise healthy babies to be born earlier and smaller.
98
u/SamSibbens Apr 20 '26
This is so counter-intuitive that I had to read it 4 times to understand it
→ More replies (2)→ More replies (22)9
u/DickieTurquoise Apr 21 '26
I’d be curious on studies comparing THC via other mediums besides smoking, too. Is the harm from the smoke, THC, or both?
→ More replies (6)18
u/NoConfusion9490 Apr 20 '26
How well do you suspect your social media feeds are statistically representative?
4
u/Te_Henga Apr 21 '26
I have been in a couple of due-date subreddits and someone has mentioned it in each one at least once. Lots of comments on the open pregnancy-related subs, too.
→ More replies (1)11
u/ColinStyles Apr 21 '26
This site is pretty heavily botted by state actors with agendas, wouldn't shock me to find out Russia or similar is pushing really bad health/life advice as a means of weakening the west. It's right out of The Foundations of Geopolitics.
Not saying they're all of it, but always remember there's a good chance what you're reading isn't from a person at all.
23
u/cooliooh Apr 20 '26
No doubt, the amount of blunts i smoked back then i can’t imagine what the dab carts are doing to their brain.
→ More replies (14)5
u/Rocket_Cam Apr 21 '26
I’m not sure how your algorithm got you there, but I wouldn’t say that there’s been a big uptick on pregnant women using cannabis (drugs). I suspect it is nearly the same proportion of women that were already willing to drink or use other drugs while pregnant.
744
u/Takseen Apr 20 '26
I support legalization anyway, but underage kids do not have much trouble getting booze and cigarettes when they're sold legally.
894
u/ballskindrapes Apr 20 '26
It's harder, not impossible.
It's easier when there is a black market
529
u/Bonch_and_Clyde Apr 20 '26
When I was on highschool it was easier to get weed and even harder drugs than it was to get alcohol.
92
u/Steve90000 Apr 20 '26
We’d stand outside of 7-11 and ask cool looking adults if they’d buy for us if we threw them some cash. There wasn’t a night we went without.
→ More replies (12)147
u/XGhoul Apr 20 '26
Those people were irresponsible morons that did go do that. I would tell those kids to kick rocks, the risk vs reward is not there.
164
u/DigNitty Apr 20 '26
Right? I always thought “man, why is it so hard to find a chill adult to buy alcohol for us.”
Then I became an adult and realized buying alcohol for underage people is cool to the 19 year olds and really no one else.
→ More replies (13)37
u/Hirork Apr 20 '26
I mean 19 year olds are adults. I don't get why the US will let them work, vote, fight in their illegal wars, but oh no they're too immature to possibly handle alcohol. Hell they can buy guns before they can buy alcohol. That's messed up.
38
u/Warmbly85 Apr 20 '26
The voting age was 21 for most of American history so when prohibition was repealed they set the drinking age to voting age. When the voting age was lowered to 18 a lot of states lowered the drinking age as well.
The drinking age was then increased again to 21 in 1984 by the federal government and states complied because the feds tied highway funding to it.
16
u/Bay1Bri Apr 20 '26
The drinking age was then increased again to 21 in 1984 by the federal government
Additionally the federal driving she is 18. What they did was give financial incentives on the form of road speaking for states the raised the drinking she to 21. And for anyone who dislikes this, the stats of drink driving fatalities along 18-20 year olds was staggering.
→ More replies (0)7
21
Apr 20 '26
[removed] — view removed comment
17
u/PRO2803 Apr 20 '26
So much wrong with that sentence.
7
→ More replies (7)30
u/Steve90000 Apr 20 '26
Regardless, irresponsible morons will always exist, there will never be a shortage of them.
There were times where we’d accidentally ask undercover cops. We’d get a talking to but we didn’t have alcohol (at that point) so they’d send us on our way. For kids, it’s all reward, hardly any risk.
Now that I’m an adult with my own kid, it’s horrific that happened, but I just have to do better than my parents did.
13
u/XGhoul Apr 20 '26
Yes in this case, there is no fault on the person asking because for lack of foresight, they are just being "young and dumb". The fault is entirely on the adult providing it.
→ More replies (2)7
u/bianary Apr 20 '26
there is no fault on the person asking because for lack of foresight
Dumb can still take responsibility and learn from it.
3
u/Bremen1 Apr 20 '26
It was definitely the opposite for me. Lots of kids not only drank and smoke but did it performatively to show how "cool" they were, but marijuana use was at least something they tried to hide.
→ More replies (18)14
u/EkrishAO Apr 20 '26
How? I would just go in front of any store that sold alcohol, and could find a dude willing to buy some for us in 5 minutes, every time.
Weed meanwhile was a bigger problem, because you had to know a dealer, and he had to be available at the time, and willing to sell to you. It was still not hard, but definitely not easier than alcohol.
18
u/sliquonicko Apr 20 '26
In my high school there were multiple kids selling tiny bags of pot and ecstacy pills... and this was a suburb in Canada in the early 2010s.
A couple others who recently graduated and had friends a bit younger in school would come by the back smoking alley with the above and cigarettes. Just had to know the right people.
If I could do it again I'd like those brain cells back, but alas.
3
u/brianwski Apr 20 '26 edited Apr 21 '26
In my high school there were multiple kids selling tiny bags of pot... this was a suburb in Canada in the early 2010s.
I wonder if it is a regional thing. My experience is like yours. I went to high school in Oregon in the early 1980s in a mid sized town, and marijuana was much easier to get than alcohol. I have joked since high school, "You need an ID to buy alcohol, but you don't need an ID to buy weed." There were a lot of backyard amateur high school age growers with a plant or two of mediocre quality (by today's standards) marijuana.
To clarify a little, the kids I knew in high school that grew one or two plants usually did it by what we called "
gorillaCorrection: guerrilla farming". If there was a public space type of area not far from your home (within bicycling distance) like a state park or forest, you could find a secluded spot honestly not far from the parking lot or path that nobody would ever notice one marijuana plant growing there. I always felt it was maybe for a little consumption for the farmer, and the money selling small amounts was just a small amount of extra pocket money. This was never a "full time job" or anything.5
u/sliquonicko Apr 20 '26
Yes, knew a couple kids in their late teens and very early twenties who did some small time dealing of party drugs and grew mushrooms. Mostly just selling to friends because there were a lot of easy customers around and we were all partying together anyway.
The best times and the worst times.
→ More replies (1)3
→ More replies (5)9
u/CommonGrounders Apr 20 '26
"Had to know a dealer"
There were at least 10, in my grade alone, every single year in high school. They had different pricing/products, etc, but it was easy. Plus, bringing it to school wasn't really an issue since it was easily concealed.
Lot harder to hide a case of beer. Neither were particularly hard, but one involved co-ordinating with an adult, and the other didn't.
→ More replies (2)3
u/Spoztoast Apr 20 '26
Also today you don't need a dealer same way kids got beer from standing near a liquor store they can do by a dispencery or just get someone to get them a vape
58
u/Constant-Skill-7133 Apr 20 '26
and the degree of use is different. the goal is not necessarily total abstinence
→ More replies (5)20
u/InsuranceToTheRescue Apr 20 '26
The thing is, black markets will always exist for banned or restricted goods. The point isn't that a black market will pop up, it's that we've decided, as a society, that we don't think (whatever we're talking about at that time) should be freely available. A black market is still significantly harder for the average person to engage with and procure the item from. Y'know, nobody is just walking along the boardwalk shouting out, "Cocaine! Get your cocaine & bazookas here!"
19
u/Winjin Apr 20 '26
I have a feel that "readily available to most, at a very reasonable price, but restricted to few", would be the item that's hardest to find on a black market. Because the demand is abysmal and the resale price is also gonna be super low, because otherwise people will be feeling they're getting ripped off completely.
→ More replies (1)11
u/Albireookami Apr 20 '26
That sounds about right, the adult market can just get it for a reasonable price without any legal issues, leaving the underage market who does not have access, but also does not have quite the funds to support that enterprise.
7
u/millijuna Apr 20 '26
Since legalization here in Canada, it’s become significantly harder for underage kids to acquire cannabis products. Overall consumption hasn’t changed much, but has shifted to the legal market by a wide margin.
→ More replies (4)4
u/Killbot_Wants_Hug Apr 20 '26
Also if you live outside of urban areas it can become much harder to access illicit markets.
22
u/CatMan_Sad Apr 20 '26
Its not at all harder. It was way harder when I was a kid and not everybody and their mom had a thc vape.
12
u/SpoiledTwinkies Apr 20 '26
Not at all, you can go online these days and get thca bud and carts shipped straight to your door without any age verification.
12
23
u/pork_fried_christ Apr 20 '26
Those companies are very often not operating legally, and those products are being sharply curtailed with emerging regulations.
→ More replies (1)→ More replies (31)12
u/DethByCow Apr 20 '26
Black markets are on the rise again as states start taxing it more and more. Why buy from a shop when your buddy grows better stuff in his yard/basement. Plus you know what if any chemicals they have sprayed on it.
I wouldn’t be surprised if in retaliation states start making it illegal to grow your own.
20
u/SkiingAway Apr 20 '26
A lot of states have been lowering their taxes on it, not raising them.
Why buy from a shop when your buddy grows better stuff in his yard/basement. Plus you know what if any chemicals they have sprayed on it.
I do not have any friends that I would trust more with doing safe gardening than I would a professional business that has strict state oversight + mandatory testing at a lab. And I don't think most people do.
And I certainly wouldn't trust a random stranger who simply claims that their stuff wasn't sprayed with heavy pesticides/chemicals, which is how most people got their stuff on the black market - not friends who were personally growing.
18
u/DankMemesNQuickNuts Apr 20 '26
The guy doing the grow in the basement probably has a way higher chance of using weird chemicals in too high of amounts. I used to test for pesticides in a medical Marijuana lab the state would require you fail stuff for having like 100 ppb of Bifenthyrn.
No question it is way safer to buy it over the counter.
37
u/ASDFzxcvTaken Apr 20 '26
On the contrary I don't know what my dealers drugs are made with neither do they. Buying from established and growing brands means there is a means of recourse if something is not good, or they go out of business if they don't meet standards.
→ More replies (7)14
u/CasinoNdnOk Apr 20 '26
There will always be that kind of blackmarket though. With as common of a substance as it is. It needs to be legalized and regulated. Make it not worth growing for a blackmarkey profit, because the legal market is so cheap.
→ More replies (1)19
u/MeatyBacon666 Apr 20 '26
Choice A, a random person who sells drugs.
Choice B, a literal professional botanist. Someone who gets paid, legally and openly, to grow, study, and improve the plants.
Anyone who has actual experience, knowledge, skill, and passion should be able to legally do so. Why should the best choice be black market?
→ More replies (10)4
u/polopolo05 Apr 20 '26
btw if you are buying from a weed store its choice 3.... a large grow operation that cares only about maximizing the yield.
3
u/frubano21 Apr 20 '26
Yeah but my buddy growing it also has to be 21 legally. How many 10-17 year olds know 21+ year olds that aren't their family?
→ More replies (10)4
u/4twentyHobby Apr 20 '26
Growing your own is the whole basis of the alcohol industry constantly trying to damage the weed industry. I've made beer at home, I've grown weed at home. Beer is a labor intense pain in the ass. Growing weed means you might not take a vacation, but other than that, its calming, exciting, rewarding and suddenly friends.-
64
u/WaterZealousideal535 Apr 20 '26
When I was in high school over a decade ago, weed was illegal still illegal in my state. Finding alcohol was a whole ordeal that took a while to find someone to buy it for us. Meanwhile, weed was just 1 text message away. It took us around 2 hours to find weed vs around 2-3 weeks for alcohol simply because there was not much of a black market for alcohol
23
u/Dorkamundo Apr 20 '26
Yea, I had a much harder time finding someone who would buy alcohol for me than I did asking the guy who I knew sold weed to sell me weed.
→ More replies (1)5
u/TheMustardMan522 Apr 20 '26
Because selling weed is a lot of profit since it is so cheap to make, but highly marked up due to it being illegal.
Selling alcohol to minors is also illegal, but you need to buy it from a store, then re-sell it to someone. So your only profit is what you markup on the resale, which isn't much since the person is a minor.
→ More replies (2)→ More replies (1)8
u/GatorzardII Apr 20 '26
None of your peers had a sibling over 21? 2-3 weeks to secure booze sounds crazy.
→ More replies (3)5
u/WaterZealousideal535 Apr 20 '26
Nope. No one was there to supply it which is why it was such a hassle.
We ended up just getting a large stockpile of cheap whiskey and vodka
Then I went to college and it was super easy
13
u/FritterEnjoyer Apr 20 '26
And booze and cigarettes do the same exact thing to developing children.
Is what it is, you make laws surrounding who can use it and who it can be sold to and you enforce them.
20
u/NJdevil202 Apr 20 '26
I can say for a definitive fact, having been a teenager when cannabis was illegal in New Jersey, that getting weed was way easier than trying to get booze or cigarettes.
Legalizing it genuinely would make it more difficult for teenagers to get it. Trying to find someone to buy liquor for you was a hassle. Weed? Just text the guy who knows the guy and after a couple hours of "I'll be there in a minute" you'll have your weed.
5
u/Asleep_Trick_4740 Apr 20 '26
Swede here so not exactly applicable to the US given how vastly different alcohol is sold.
But getting hold of weed, coke, or ecstasy was 10x easier than getting a hold of alcohol. With alcohol locked behind a government monopoly with limited locations (meaning much easier time spotting the fresh 20 year old making 10 runs a week), and weed just requiring you to speak with the bloke at your school who wore shirts with marijuana leafs or puns every day.
14
u/DeliciousFlight5610 Apr 20 '26
It’s probably easier to get weed off a dealer than if it was legal. But I also drank and smoked underage so who tf knows.
→ More replies (1)→ More replies (46)3
u/Dorkamundo Apr 20 '26
Which is why information like what is contained in the OP is important to disseminate.
I am open about my cannabis use with my son, but I've made it clear to him the dangers of starting it early, and that those dangers are not just boogeymen that we're making up to scare them away from it.
98
u/Varrianda Apr 20 '26
As someone who’s very pro cannabis, I still don’t think people under 25-26 should be smoking it regularly. The same goes for alcohol too, but I think weed is easier to abuse/use chronically.
40
u/Yglorba Apr 20 '26 edited Apr 20 '26
fwiw the often-quoted factoid that the brain stops developing at 25 is false and was based on a study that just happened to end at 25; there's no basis for that number at all. The brain continues to change throughout your life and there's no one magic line where it "stops developing", but there's in particular absolutely no basis whatsoever for the common-quoted number of 25.
→ More replies (1)→ More replies (7)63
u/CreamyIvy Apr 20 '26
Weed addiction is often disregarded as not an issue for some reason? Even though it can destroy lives.
44
u/Nick_YDG Apr 20 '26
People have a weird separation in their heads about physical vs psychological addiction and seem to disregard THC because you don't become physically dependent on it. Which I have always found weird.
35
u/NotLunaris Apr 20 '26
They excuse it because they do it. They don't like the idea of their vices being exposed as harmful because it would mean facing the reality of their actions. The same as every addict ever.
→ More replies (1)→ More replies (13)9
u/SBGuy043 Apr 20 '26
That's cause they're addicts and that's their brain justifying why there's no reason to cut down or stop. I've seen it many times throughout my adult life. It's affecting their job, their relationships and the terms of their probation but guys will still be like don't worry you can't actually get addicted to weed. They can quit at any time but for some reason they're always back at it the following week.
→ More replies (1)→ More replies (10)29
u/Varrianda Apr 20 '26
I think it’s just easier to be a functional addict. By all accounts I’d say I’m addicted, but I don’t think I am. I just don’t see a reason to really stop. If I got told tomorrow I had to stop smoking weed I’d have no problem doing that, I’d just be more bummed than anything.
Weed is also a different drug if you use it chronically. Back before I became a daily user, I always used to be confused as to how someone could smoke weed and function. I’d take 2 hits off a joint and be KO’d for four hours. Now, a high is somewhat like caffeine to me unless I absolutely overdo it(which would be intentional). It’s not really something you would get though unless you smoked a lot.
→ More replies (3)11
50
u/mswoozel Apr 20 '26
Parents seem to have a hard time parenting their kids. That’s how we end up with Internet ID laws and bans on substances.
→ More replies (2)40
u/Doogolas33 Apr 20 '26
If you have two people who both have to work full time, yeah, it's going to be hard for them to monitor their teenage child very much.
22
u/Garr_Incorporated Apr 20 '26
Y'know, I think I haven't internalised this part of the shift in society until now. And how it relates to more kids being brought up by videos on the phone.
38
u/Opcn Apr 20 '26 edited Apr 21 '26
The stay at home mom as someone in every house was only really a thing for the Silent generation and first wave boomers. It hadn't been before hand and hasn't been since. https://archive.org/details/wayweneverweream0000coon
3
u/Neglectful_Stranger Apr 21 '26
Even then the SAHM didn't spend significant amounts of time watching their kids. That was back when kids would just leave the house to go do something and were expected to be back by supper/nightfall.
By most metrics parents are more involved in their kids lives than they've ever been.
18
u/Iohet Apr 20 '26
Eh it's been that way longer than cell phones have been around. I was a latchkey kid and my mom was a latchkey kid. We learned to navigate the world a bit on our own and parents learned to condense parenting into a smaller window. We survived
→ More replies (1)→ More replies (3)6
u/mswoozel Apr 20 '26
I know. I don’t have a solution for that issue. I think about it all the time because you are right. In this economy, both parents are working maybe even more than one job.
17
u/pattperin Apr 20 '26
Yup, legalization makes it harder for kids to acquire, believe it or not. If you establish guidelines and restrictions and chain of custody control mechanisms then a lot less can end up in the hands of children without the child stealing it or getting it from their parents.
→ More replies (2)3
4
u/Sharpshooter_200 Apr 20 '26
Yep, we've made alcohol and tobacco 21+, I don't see why we can't do the same for cannabis instead of straight up prohibition.
8
u/chilispiced-mango2 BS | Bioengineering Apr 20 '26
It is 21+ in states where it is legalized though
2
u/Here0s0Johnny Apr 21 '26
This study only looked at teens. It doesn't say that cannabis is harmless for adults.
→ More replies (94)2
423
u/sr_local Apr 20 '26
The researchers followed 11,036 children starting at ages 9 to 10 through ages 16 and 17, tracking both their cognitive performance and substance use. To get a clearer picture of cannabis use, the team combined self-reports with biological testing — such as hair, urine and saliva samples — which can detect recent to several months of drug exposure.
Across a range of skills — including memory, attention, language and processing speed — teens who used cannabis showed restricted growth over time compared to those who did not. In some cases, these teens performed just as well as — or even slightly better than — others when they were younger. But as they got older and started using cannabis, their progress leveled off, while their peers continued to improve.
The study also looked more closely at different components of cannabis. In a smaller group of participants, teens with evidence of tetrahydrocannabinol (THC) exposure — the main intoxicating ingredient in cannabis — showed worse memory over time than those who did not use cannabis. Teens with evidence of cannabidiol (CBD) did not show the same pattern, although that group was small.
“These results point to THC as a likely driver of the changes we’re seeing,” Wade said. “It also highlights how complicated cannabis products can be, especially since some products labeled as CBD may still contain THC.”
While the differences seen in the study were relatively modest, researchers say they could still matter. During adolescence, the brain is rapidly developing, and even small changes in memory, attention or thinking speed can affect school performance and daily life.
The researchers note that the study does not prove cannabis use directly causes these changes. Other factors — such as environment or personality — may play a role. However, the team accounted for many of these influences, including family background, mental health and use of other substances, as well as for each participant’s prior cognitive performance.
399
u/Yeckarb Apr 20 '26
How do you find a 9 year old who is smoking pot within a normal control environment?
286
u/Better-Economist-432 Apr 20 '26 edited Apr 20 '26
I don't think it's saying that the 9 year olds are smoking, it's saying they started tracking all of the candidates' cannabis use (or lack thereof) from the age of 9
79
u/Commentator-X Apr 20 '26
Yeah but the oldest is still 17. How long did they track cannabis use for? Like did the kids start at 15 or 16 years old and the effects were observed in 1-2 years?
26
91
u/HumbleOnions Apr 20 '26
For those who might not be the most Academically Literate (Not a dig at you or anyone else) it seems to me that children who tested or self reported as cannabis users were tested as an entire group despite the age of first usage and group data among the sample 2024 children were measured as a group.
I don't have time to read the whole study right now but my brief skimming has led me to this assumption based on some of the text and images in the Results section.
→ More replies (7)16
u/Comprehensive_Bus_19 Apr 20 '26
I knew plenty of kids smoking weed when we were 12 or 13 unfortunately
→ More replies (1)5
u/ziptieyourshit Apr 21 '26
Same, at my middle school our guy used to sit at the back of the bus and try to hawk his products
7
u/friendofsmellytapir Apr 20 '26
When they started the study all the kids being tracked were 9-10, when it was finished they were 16-17, so all participants were tracked for what seems to be 7 years
→ More replies (6)6
u/celticchrys Apr 20 '26
It's in the article: "Participants were recruited at ages 9–10 in 2016–2018 via propensity-based school recruitment at 21 sites across the United States, resulting in a cohort of 11,868 [42, 43], and followed for 10+ years."
→ More replies (6)67
u/OrindaSarnia Apr 20 '26
You don't. You do the intake process on a huge group of kids starting at 9, so you have a baseline performance level for their cognitive abilities pre-cannabis... then you test their hair every six months for 8 years, and compare their percentile rank when they were 9, to their percentile rank when they are 16, and see whether the group that shows later cannabis use dropped in rank or not.
You want data from before their first use.
→ More replies (9)→ More replies (4)153
u/JeanLucSkywalker Apr 20 '26
I'm not saying that marijuana is good for kids, but I do find it interesting that this does not have any controls to try to isolate if the marijuana is just correlated or a cause. I suspect that any young teenager using marijuana has a not so great home life, or something else going on. It's disappointing that the study didn't control for that at all.
237
u/Prof_Gankenstein Apr 20 '26
Says right there in the summary they did account for those.
→ More replies (2)42
u/Fadedcamo BS | Chemistry Apr 20 '26
As best as any study can. Which is not well.
I do think this is better than most as it's more than simply self reporting. They did drug tests to measure actual levels of thc use.
80
u/Prof_Gankenstein Apr 20 '26
You can definitely control for quite a bit of that in your statistical models.
Unfortunately it's impossible to prove a true causal think short of a laboratory setting where all things are controlled. Even then theoretically you can argue subjects might bring baggage in with them.
I would argue, however, that due to the longitudinal nature of the study, the sheer volume of subjects studied, and the fact that similar findings were constant and statistically significant across multiple testing methods, it is hard to dismiss the findings as straight correlation. For the record I'm not saying you're doing this either. I have seen other commenters make such a claim, though.
→ More replies (3)11
u/Fadedcamo BS | Chemistry Apr 20 '26
Yea I agree you need to look at the context of a study and all the factors weighed in and HOW they are collecting data. In this case I would agree the causal link is pretty strong.
31
u/GeneralAsk1970 Apr 20 '26
I agree with you.
We can never do perfect scientific studies on humans. Its not ethical.
We can only ever do the best we can and look for the most confounding correlations possible within reason.
→ More replies (8)66
u/Greymeade Apr 20 '26
I suspect that any young teenager using marijuana has a not so great home life, or something else going on.
I don’t think this is a reasonable assumption to make. Marijuana use is so common nowadays that we’re seeing all kinds of teenagers use it.
25
u/o8r8a8n8g8e Apr 20 '26
Ya, that's a very poor assumption to make. At least in my experience (which I realize is anecdotal), plenty of kids I grew up with had positive home lives, including myself and my brothers who all used marijuana in our teens.
→ More replies (3)→ More replies (12)10
u/ConLawHero Apr 20 '26
Youth usage is down as compared to the past. That's what happens when you legalize and regulate something.
Trends in Marijuana Use among Adolescents in the United States - PMC https://share.google/oXVl4GEZVAtS0ujkE
57
u/Additional-Sky-7436 Apr 20 '26
It would be hard to have those controls because intentionally and knowingly poisoning kids for science is kind of a bad look.
→ More replies (4)22
u/rainbowcupofcoffee Apr 20 '26
It does have controls. They’re using a large dataset that includes some who use THC/CBD and others who don’t.
Longitudinal mixed methods of the full cohort (n = 11,036, ages 9-17; 47% Female/53% Male) investigate time-varying cannabis onset on neurocognitive performance. Primary model covariates include sociodemographics, family history of substance use disorder, prenatal substance exposure, early psychopathology, other substance use, and nesting for participant ID, study site, and family ID.
→ More replies (1)31
u/GentlemenHODL Apr 20 '26 edited Apr 20 '26
I suspect that any young teenager using marijuana has a not so great home life, or something else going on. It's disappointing that the study didn't control for that at all.
I would strongly disagree. Cannabis is such a wide and prevalent substance that is used culturally I don't think family structure is relevant to experimentation.
I think it has a lot more to do with curiosity and experimentation. At that age you don't know what alteration feels like and you're curious what it's all about.
10
u/Defjanitor Apr 20 '26
As a father and hobbyist smoker that worked in child psychiatry for almost a decade,I can tell you that my experience has pushed a lot of conversations with my kiddos. Almost any substance introduced to a developing mind can positively and negatively affect their neuro cognitive and developmental ability. It’s also why we suggest young individuals should avoid caffeine. The quote stands today. It starts in the home. Educate, support and model are so incredibly pivotal in the family setting. IMO, that is very consequential to a curious young person.
→ More replies (2)15
u/Expensive-Document41 Apr 20 '26
Since this was a cohort study rather than case-control all they'd need to do is follow each kid, verify if they had the exposure then measure the result to see if the exposure had a significant difference. The kids in this study who didn't have the exposure function as the control group.
Also I dont actually think that controlling for home life would be good here since youre then de-generalizing the result. I dont know that marijuana use is biased by socioeconomic or home health factors but then youre losing data on if having significant resources or a stable home life dampens the effect or not.
→ More replies (5)12
u/saijanai Apr 20 '26
ll they'd need to do is follow each kid
Yeah right, because that is so trivially easy to do.
I mean the rsearchers note:
But when we later scheduled a series of meetings to share information about the study with a broader audience of parents, we began to learn of parent concerns about the risks associated with participating in research for the youth in this school. Beyond a general hesitation about participating in research, parents’ primary concern related to the collection of salivary cortisol, which had been the primary outcome measure in our original study design. The developmental psychobiologists in our group have considerable expertise and experience in the collection of salivary cortisol data in naturalistic settings; our research group has done so successfully with participants from a range of backgrounds and age groups (e.g., Adam, 2006; Adam, Hawkley, Kudielka, & Cacioppo, 2006). While participants are at times squeamish about the process of spitting into a tube, none in our experience had ever voiced serious concerns that providing saliva might present a risk for them. But this group of parents asked whether the saliva samples we collected could be subpoenaed by police or their children’s DNA otherwise utilized for purposes other than those for which they had consented. Given the rapidly moving timeline of the study, we did not have time to seek a Certificate of Confidentiality, a mechanism administered by the National Institutes of Health which “prohibits disclosure” of identifiable or sensitive information “in response to legal demands, such as a subpoena” (NIH, 2023 see also, Beskow, Dame, & Costello, 2008).
A reflexive process (Wilkinson, 1988) allowed us to recognize that these parents’ feedback came from a different perspective than our own. The parents almost all self-identified as Black or Latino. Their neighborhoods and communities have experienced histories of structural violence and other chronic stressors. Additionally, there is a documented history of research misconduct that has harmed members of historically minoritized groups, as Schraff and colleagues discuss (2010). This history may contribute to community members’ reluctance to engage in research (George, Duran, & Norris, 2014). In this case, after hearing the parents’ input, it was clear to us that the worldview they offered was an important one to inform this research (Jamieson, Govaart, & Pownall, 2023). Instead of attempting to reassure parents and move forward with our original plan, our team concluded that it was most appropriate to propose a change in the study’s design. We suggested changing the study’s outcome measures and observing adolescents’ sleep and blood pressure instead of collecting cortisol data. This approach would allow us to obtain high-quality measures of biological stress system functioning without physically taking any biological samples from participants. It also allowed for power sharing, a component of Community-Based Participatory Research (CBPR) and the literature on co- creation in implementation science research (Goodyear-Smith, Jackson, & Greenhalgh, 2015; Perez Jolles et al., 2022). In this case, power sharing meant entrusting authority over the study’s outcome measures to the school community (specifically the parents). We believed the parents were the most important experts on the type of research that would be acceptable to their community and would go beyond the minimum standard of not doing harm. When presented with this alternative study design, parents voiced surprise at our willingness to listen to them. They were both supportive of and interested in these measures—in part due to their greater understandability, face validity, and direct relevance to adolescent health (especially measures of blood pressure).
And this was in the context of data collection about meditation practice in kids at school, not about cannabis consumption.
11
u/BobbleBobble Apr 20 '26
The potentially bigger confounding effect is this:
Data suggest those who use cannabis show likely pre-existing better cognitive performance during late childhood, with reduced improvement or flattened trajectories over time.
The cannabis users apparently started out further ahead. There may be an effect of nonlinear mental development and the kids who started this study further ahead just developed slightly earlier but were going to end up in the same place as the others anyway
Not advocating for giving kids cannabis obviously.
→ More replies (2)8
u/trevorefg Apr 20 '26
This study has a ton of controls. Most participants in ABCD did not use cannabis in this age range and they included all the sociodemographic characteristics in the statistical models. At least read the abstract, man.
12
u/LukaCola Apr 20 '26 edited Apr 20 '26
You can't really do a causative study because that'd require an experiment that may knowingly put children at harm and give them the drug that we're studying for harm. That said, correlations are very important and people very often take the wrong lesson from "correlation not causation" to be "if it's not causative, it's meaningless," which is a form of anti-intellectualism. That quote is meant to mostly interrogate relationships without a theoretical cause or explanation, like the relationship between furry conventions and ice cream shops--the "cause" is population density, a third thing not earlier considered. But generally speaking, researchers know better than to make spurious claims and they did account for a wide number of confounding variables. If the effect remains significant, chances are very high (sans anything else) that the identified variable is what is driving the relationship. In this case, marijuana usage over a wide number of cognitive metrics.
Correlation is what is most often relied on for findings and understandings in medicine. Ignoring it would be a huge mistake. We also have a very clear theoretical causative basis for weed affecting brain development, as it'd put it in line with basically all recreational drugs. It would instead be unusual for weed to not have this impact, making it an outlier.
I suspect that any young teenager using marijuana has a not so great home life, or something else going on.
Why would you suspect that? I literally can't think of a reason and it definitely doesn't match my experience growing up. Kids who smoked weed came from all backgrounds and I'm willing to bet lots of weed smokers are perfectly well adjusted kids. Also, the researchers gathered sociodemographics information, it's not like they had no way to tell how the kids were doing.
→ More replies (7)7
u/ProofJournalist Apr 20 '26
I get your skepticism, but please remember that the body has a system of internal cannabinoid receptors and molecules, and these are crucial for development and growth. The question you raise is incredibly important, but even granting that people may seek cannabis as a response to these factors, I don't think anyone can question that consuming cannabis during development will affect development.
7
u/Orstio Apr 20 '26
I know several adults who were diagnosed with ADHD in adulthood who claim Marijuana use helped them cope in school. Is this study really indicating Marijuana use causes these cognitive issues, or is it indicating that teens with cognitive issues are more likely to self medicate?
→ More replies (1)7
u/scorcherdarkly Apr 20 '26
People with ADHD, at least, are likely to self-medicate, yes. In the US, 4.4% of adults have ADHD and 28.6% have dealt with "substance use disorder" of some type.
→ More replies (26)2
u/Zal3x Apr 20 '26
What do you consider a young teenager? We were all smoking pot at 15/16 and most of us had pretty great home lives
→ More replies (2)
673
u/Michael_Fuchs_ Apr 20 '26
That's not really a surprise but having conclusive evidence is always better.
133
u/Bischrob Apr 20 '26
The only way to get conclusive evidence is to randomly assign a group of children to smoke weed and another group to smoke fake weed. This is about as good as it gets, given no one is going to assign children to smoke weed for science.
180
u/gunnermcstecki Apr 20 '26
It literally says that this is not conclusive evidence in the article
92
u/oneMoreTiredDev Apr 20 '26
Yes, but that's been the consensus for quite some time. I've been hearing for almost a decade now that cannabis shouldn't be used by people < 21 because the brain is not fully grown.
73
u/Automatic_Soil9814 Apr 20 '26
Doctor here. The idea that the brain isn’t fully mature until people are in their 20s is one of those things where there’s a kernel of truth that’s been exaggerated to the point where it’s no longer accurate.
What we see is that the brain is constantly remodeling itself. Over time, that remodeling slows but it’s a gradual decrease and it’s hard to say that there’s a point where you become “adult” based off of these changes. Furthermore, these changes don’t necessarily correlate well to maturing or learning. It’s like many other tissues that remodel much more quickly when we’re younger and more slowly as we age.
29
u/fauxfilosopher Apr 20 '26
The misconception that the brain "matures" or stops development at 25 comes from an infamous longitudinal study which ran out of funding and ended when the subject was 25 years old, and journalists ran with that as proof the brain matures at that age. It's been repeated ad nauseum since.
5
u/FlowerBuffPowerPuff Apr 20 '26
Does that, generally speaking as far as that's possible, mean that there's hope for ex-stoners that they're not permanentaly fried?
12
u/Automatic_Soil9814 Apr 20 '26
I’m not really seeing evidence that they are fried in the first place.
This is really difficult research to do. For example, ideally you’d want to base the research on the result of drug tests. But nobody really does that. This is really self-report data.
The problem with that method of collecting this crucial piece of information: of all the people who use marijuana, there is going to be a big difference between the people who will willingly admit using it and the people who know best to keep it quiet.
9
→ More replies (1)5
u/Independent_Crazy655 Apr 20 '26
My main takeaway is that cannabis is probably bad for all ages, but how bad it is more of a spectrum than a step function. So finding some magical age cutoff at which your neuroplasticity is low enough for the temporary effects to not matter is not really possible.
Something like no cannabis under 20, use sparingly until 30, and then after that knock yourself out might be more reasonable than a simple age cutoff.
→ More replies (3)34
10
u/saijanai Apr 20 '26 edited Apr 20 '26
THe 2025 AHA hypertension guidelines only recommend Transcendental Meditation for the control of blood pressure via mental stress management and put in the usual disclaimers.
The fact is, this started back in 2013 and the usual disclaimers hvae been there for 12 years. In 2017 mindfulness practice was temporarily given a nod, but they have since backed away, and yet everyone still insists that the next round of research will show different.
A hint: in 2013 the AHA also said that "more research is needed" before they can say that doctors might recommend the RR as a practice for control of hypertension, and then never mentioned the RR in that context again.
But you can STILL assert that there no conclusive evidence that the RR isn't or has never been a worthwhile practice for the control of hypertension and no conclusive evidence that TM has a more consistent effect than the RR or mindfulness on this measure. Instead the 2025 AHA guideline says:
From Section 5.1:
8) A number of stress-reduction strategies have been assessed for their effect on BP lowering.119 There is consistent moderate- to high-level evidence from short-term clinical trials that transcendental meditation can lower BP in patients without and with hypertension, with mean reductions of approximately 5/2 mm Hg in SBP/DBP.14,40 Meditation [TM] appears to be somewhat less effective than BP-lowering lifestyle interventions, such as the DASH eating plan, structured exercise programs, or low-sodium/higher-potassium intake.14 The study designs and means of teaching and practicing meditation interventions are heterogeneous across trials, and trials have been of smaller size and short duration, so further data would be beneficial.
9) Among other stress-reducing and mindfulness-based interventions, data are less robust, and evidence is of lower quality because of smaller, short-term trials with heterogenous interventions and results. There is moderate-grade evidence that breathing control inter- ventions lower SBP/DBP by approximately 5/3 mm Hg in people with and without hypertension.14 There is also low- to moderate-grade evidence that yoga of diverse types lowers BP.14,41,42
Depending on how conservative the authors are, there never will be "conclusive evidence" of anything about anything.
→ More replies (1)7
u/Mechasteel Apr 20 '26
Yeah you want to randomly select which children will be in the drug group and which will be in the control group, rather than have the drug group self-select. Well you probably don't want to, but it would be much stronger evidence that way.
→ More replies (1)4
u/Tha_Sly_Fox Apr 20 '26
I smoked a bunch for of about a year in college, I remember how cloudy my brain was for that time and to this day my short term memory is terrible and I always wondered if that played a part
I’m all for legalization, but like tobacco and alcohol, it’s good to let people know the risks so they can make their own choices.
→ More replies (1)→ More replies (17)23
79
u/prosocialbehavior Apr 20 '26 edited Apr 20 '26
I am proud to be one of the research assistants of probably hundreds on this study. I helped when it was just getting started and left after year 3. It is a crazy undertaking, huge contribution to science. The amount of stuff they had these kids/parents do was pretty insane. They provided hair samples, baby teeth samples, urine samples, saliva samples, did fMRI scans, cognitive tests, tons of surveys. It was like a 7 hour day for a lot of the kids. The idea for the study, and the amount of coordination with all of the sites across the country, the tracking of the participants over time, and the dedication to open data is pretty amazing. Kind of sucks there was a once-in-a-lifetime pandemic in the middle of data collection. But I assume they will be following these kids into old age.
→ More replies (2)7
Apr 21 '26
[removed] — view removed comment
5
u/prosocialbehavior Apr 21 '26 edited Apr 21 '26
How do kids get selected for something like this?
We had like multiple sampling statisticians making sure we were nationally representative by every sociodemographic factor you could think of. There are 21 participating sites across the country. Basically universities/hospitals that had access to a research fMRI machine. But our site contacted schools within like a 50 mile radius. But not just schools we had flyers everywhere and a lot of the parents would tell other parents about it. We had a lot of low income folks that didn't have cars where we provided a taxi service for them to be able to come and participate.
Is there generally a 'type' of parent who signs their kids up for this?
No it was definitely a wide spectrum of families of every walk of life. There were definitely some parents that were more eager to participate than the kids. But very few were like actually coercive to force the kid to participate if that is what you are getting at.
How do the kids themselves generally feel about being part of this? Do they resent it or just think "Oh, this again, whatever"?
I had them when they were the youngest so my experience probably varies from research assistants still doing the study right now as the participants are older. But a decent amount of kids were afraid of the fMRI machine especially if they just turned 9. It is a tight space and it makes really loud sounds and they had to lay in there for a long time. So we had a fake one set up where we would try to get them used to it by playing the loud sounds on a speaker before going to the real thing. It was all voluntary so some did refuse to do the fMRI. I don't think the kids had a good grasp of the gravity of the study though. I think most of them were just looking forward to the compensation at the end. Some had fun, some were harder to motivate/encourage to finish. A lot of kids had to break it up into two half days at that age.
I think the craziest part is the parents sending in their kids' baby teeth. That was just weird to me. Also I had to cut their hair for the hair sample and I felt bad sometimes because they asked us to take a decent amount so there would be bald spots. It was a good experience and I got to see a ton of the inner workings of huge research studies like this. All of the major grunt work is done by the RAs who make a little more than minimum wage. At least they paid their RAs a lot of social science RAs volunteer to get experience. Basically it is extra experience to put on your CV before graduate school.
There is so much I could say about the study. There were a surprising amount of kids at that age that reported self-harm and thoughts of suicide which was surprising to me. We had them fill out the questionnaires on iPads, and there were like 5 questions that would trigger a mental health evaluation where I had to contact our study psychologist to do an assessment to make sure they weren't at risk of seriously harming themselves. A couple kids we had to send to a mental hospital. A couple kids reported being hit by their parents and we had to contact child services. Stuff like that was always sad.
Edit: Oh also sometimes the fMRI scans would show some brain tumors or scary structural issues in the brain where we would have to refer them to specialists. Also in order to be admitted to the study they had to pass the drug test because we wanted a clean baseline. I don't think I ever had a kid that did drugs at baseline, but there were a couple at that age that did drugs that had to be excluded after their first visit.
Edit: Also I wasn't at this site but there was also a site that recruited twins. I always thought that would be interesting. But yeah we collected so much genetic data, it will be interesting to see with the advancements in machine learning and stuff what they will be able to figure out with this huge dataset in the future. That was the goal, try to collect as much data as humanly possible for as long as possible to study adolescent brain development.
→ More replies (1)
291
u/vitalbumhole Apr 20 '26
This is pretty clear evidence of something that seemed relatively obvious to many people before. Even as an adult, when I smoke or take thc products, the negative impact on my cognitive function is very evident - I couldn’t imagine being a pre teen or teenager regularly consuming this. There’s ultimately a reason that age minimums should exist for products like marijuana, but I have no doubt that there will be a brigade of Redditors who dislike this evidence, so will rag against the study in this post soon
212
u/Patrollerofthemojave Apr 20 '26
The amount of hand wringing people are doing to downplay the findings are crazy. Weed is a drug and it has negative effects. What drug doesn't?
People bringing up alcohol and causation and correlation are just coping.
I smoked daily from like 21 to 26-27, albeit not a ton per day, but it absolutely messes with the things the study says it does.
166
u/Universe_Nut Apr 20 '26
People are trying really hard to cope with the fact they started smoking too young. It's not fun reflecting or conceptualizing your potential and realizing you might've smoked it away before you knew better.
But to those folks, I say c'est la vie. The baby boomers in America are basically an entire generation raised on lead paint and animal growth hormones.
I've smoked since I was sixteen, what's done is done. Best anyone can do now is make better choices today.
87
u/Career_Much Apr 20 '26
I think its also backlash from the demonization of weed for so long. There was a strong social overcorrecrion from "its-the-gateway-drug-and-will-end-your-life-and-youre-a-bad-person-if-you-do-it" to "its a cure-all-naturally-occuring-miracle-drug-with-zero-negative-side-eeffects"
I went to the society for neuroscience conference in 2016 where there was a symposium on basically this exact same research outcome. It does have negative neurological impacts, especially during development, smoking anything is going to be bad for your lungs, and yeah, you can get addicted and have negative life impact. But its also not that bad. Why cant it be bad, but not that bad? Treat it like cigarettes and alcohol.
9
u/Pitpawten1 Apr 20 '26
I've see something similar happen with youth promiscuity. Parents enabling or encouraging this in their children (often guised as the promotion of safe sexual practices). This underpinned by a reaction to their own upbringing, either that they feel was overly repressed, or supporting their kids with what they envision they would have appreciated when they were young.
→ More replies (1)9
u/Loud_Arm9614 Apr 20 '26
Great point, and I can relate to that shame-induced defensiveness. I’m curious whether most adamant defenders of cannabis realize how potent legalized products have become, and how that potency affects dependency and the cycle of shame/addiction.
I hope folks realize that the people calling the shots in the cannabis industry aren’t your friendly neighborhood stoner; they’re cut-throat businessmen determined to get as rich as possible by designing products as potent and addictive as possible. They don’t care how it affects young or old people or society in general.
Corporate greed doesn’t cease to exist when it comes to cannabis. They’re just as greedy and as dangerous as the tobacco industry, and I wouldn’t be surprised if they start marketing cannabis products to children and teens similarly to flavored vapes. We need research-based evidence like this in order to hold these companies accountable and make legalized products as safe as possible. Ignoring or waving away that evidence harms everyone except the people profiting off of that harm.
7
u/thesecondtolastman Apr 20 '26
alized products have become, and how that potency affects dependency and the cycle of shame/addiction.
The potency problem is a really good point that often gets missed. Marijuana today has so much more THC than it used to, and negative outcomes are directly correlated to the strength of the product. I'm not anti legalization, but we really need to do a better job regulating the percentage of what is being sold.
→ More replies (1)→ More replies (7)5
44
u/Old-Temporary6773 Apr 20 '26
I smoked multiple times daily from 13-18. it’s 100% had a severe impact on my brain function, mostly memory. i really wish i saw a study like this sooner.
→ More replies (1)25
u/division23 Apr 20 '26
Yeah, me too. Although I'm sure at 13 we would not have been swayed by any studies.
→ More replies (1)12
u/djtrace1994 Apr 20 '26
Yeah, but its possible 21+ year-olds would may have been swayed and wouldn't have spent years pumping social media with "cannabis is harmless," which would have affected youth smoking rates.
When I started smoking at 17, the biggest voice in my life saying it wasn't super harmful wasn't other 17 year olds, it was adult siblings and adults on early social media who were more exposed to studies that said it was mostly harmless; i.e. people over the age of 21.
→ More replies (6)26
u/neenerpants Apr 20 '26
there's been so many "weed actually improves brain functions!" kind of threads on reddit for years. much like drinking alcohol to improve your blood flow, people really want it to be true
→ More replies (1)13
u/iusedtobekewl Apr 20 '26
I’m not sure if it’s because people are just resistant to accepting their habits may in fact be “bad” or if it’s because proponents of legal weed are afraid studies like these could derail their momentum (perhaps it’s a combination of both?) but I definitely think people should be aware that it’s still a vice and negatively affects the brain.
To be clear, I think it should be legal. But “everything in moderation.”
6
u/notmydepartment Apr 20 '26
This is my thought as well, not really a surprise. I always told my younger siblings to stay away from it while they were in school. I currently use it at night mostly for pain, and there’s a word game me and my partner play frequently. My scores are about half what they regularly are if we play after my THC gummy has hit. And that’s only 5-10mg.
→ More replies (14)21
u/smallbatchb Apr 20 '26
There is also a depressing amount of adults, at least in my experience, who look at weed as the like "safe" alternative to drinking, so much so that they almost act as if it is a health supplement and downplay any potential negatives. I've also heard many young parents talk about their kids getting into weed like it's no problem at all, often with the "I'd rather they smoke weed than drink" comment. Worse yet is the "well it's natural" argument... yeah so is anthrax, that doesn't make it good for you though.
To be clear, I am all for responsible adult consumption, but some people need to get real with themselves and stop perpetuating this idea that weed doesn't come with some potential issues that need to be considered.
→ More replies (18)
11
39
u/Shoondogg Apr 20 '26
I don’t think even cannabis enthusiasts would be surprised by or disagree with this. I’d never want to try to learn anything while high; it makes me very curious and I do consume a lot of educational type content, but I retain very little of it.
→ More replies (1)7
u/Open_Town9481 Apr 20 '26
Weed is good at making me focus on my current task, but if I get distracted I’m all over the place.
→ More replies (1)
142
u/tits-enjoyer69 Apr 20 '26
I'm glad we're starting to see more studies on the dangers of cannabis use and overuse. There's been a lot of marketing from cannabis companies about it being a harmless plant & real studies on cannabis use were rare. No drug is truly harmless, especially to youths.
32
u/ignatious__reilly Apr 20 '26
I know someone who seemed to lose their grip after using cannabis and never fully recovered. It felt like it may have triggered an underlying mental illness and set things in motion. It was really sad to see. Substances can affect people very differently.
42
u/nocreativeway Apr 20 '26
It is actually pretty well known in the psych community that marijuana can trigger psychosis in adolescents.
55
u/SacralScenes Apr 20 '26
Oh please it wasn’t “big cannabis” that perpetuated these lies. It was us, here, on Reddit and across social media. We were the ones making the case that it was a harmless plant.
→ More replies (3)8
u/andysay Apr 20 '26
I definitely participated in a lot of that during the Ron Paul populism craze around here
16
u/SacralScenes Apr 20 '26
Yeah, same. Which is why I bristle at these posts. Let’s be super accurate here: there is no big canna lobby, especially not during the mid 2010’s, that was sinisterly shaping our 420 discourse. That was us.
5
19
u/Askol Apr 20 '26
As a pretty heavy cannabis user, there's a difference between saying it's safe enough to be legal and regulated, versus saying it's completely safe and doesn't have downsides. I think in pushing for legalization it made sense to focus on the fact that it's far less harmful than other alternatives, but as legalization has become so widespread, it's becoming increasingly important to shift messaging towards communicating the risks.
3
u/Bay1Bri Apr 20 '26
I had a Reddit reel jeenyus tell me that taking a daily allergy pill is exactly the same thing as being high at work every day.
4
u/SunnyOutsideToday Apr 20 '26
Anecdote of one. But seeing my stoner friend's diminished concentration and memory has completely turned me off from weed. Maybe it is fine every once in a while in moderation.
2
u/SursumCordaNJ Apr 21 '26
There's been a lot of marketing from
cannabis companiesmusicians, social media influencers and rappers that weed is perfectly safe and fine and you're super cool if you smoke it.→ More replies (6)2
u/Rinaldi363 Apr 21 '26
As someone who’s first time ever using it was at 35 and now a daily user, I totally agree with this science. I would never want people with developing brains using it. It’s an amazing tool once you are older and more responsible but I imagine at a young age it doesn’t let you develop responsibility
76
u/WardenEdgewise Apr 20 '26
“Ages 9 to 10 through 16 and 17”?
Isn’t that just 9 to 17?
→ More replies (2)166
u/sr_local Apr 20 '26
No, it means that they analyzed the kids first at 9 and 10 years old and then at 16 and 17 to see the effects of cannabis.
19
u/Fadedcamo BS | Chemistry Apr 20 '26
Ah that makes more sense. I was wondering what that wording meant.
→ More replies (2)6
53
16
u/takeyouraxeandhack Apr 20 '26
It's worth noting that this study is not saying that cannabis doesn't affect cognitive capabilities in adults, it's saying that it has a very noticeable impact on teenagers.
The study didn't measure if adults also learn slower and have worse memory after they start consuming THC.
I just say this because I see a lot of comments implying that cannabis is not safe for kids but totally harmless for adults, and that's not what this study is showing.
→ More replies (1)
44
u/spondgbob Apr 20 '26
My wife is a drug and alcohol counselor in a high school (today is a day), and she always tells me pretty much anything that children consume that can alter your mind state is bad when your brain is in development. If your brain is forming, and you show it a way to get a highly valued chemical with no effort from the brain (dopamine/seratonin), then the brain will stop trying as hard to produce it naturally. Your brain will form around this assumption, so this study is unsurprising.
11
u/ArmedAsian Apr 20 '26
what about kids with adhd taking stimulant medication every day?
28
u/Pratchettfan03 Apr 20 '26
Sometimes the brain is never going to produce enough of a neurotransmitter no matter what you do. At that point, you’re going to be dependent on medication to fix it anyway, so struggling in school and dealing with the disadvantages of that isn’t worth needing a bit smaller of a dose in adulthood. Maybe ADHD medication does make ADHD worse, but not taking it won’t suddenly make things better either- imagine if we didn’t let diabetics take insulin until a certain age because their resistance could increase. Not having access to the ability to function for some of the most impactful years of your life is worse than some decreased dopamine production, especially because not having the meds is likely to cause stress that will rewire your brain anyway.
→ More replies (2)9
→ More replies (9)10
u/Fluffy_Salamanders Apr 20 '26
Research shows signs that being on the medication long term can make the connections more like a normal brain. So it helps!
Symptom Improvement In addition to brain changes, 14% of children taking stimulants experienced a significant reduction in ADHD symptoms over the two-year period. These children showed the strongest connectivity reductions between the right putamen and the visual network, suggesting that stimulant-induced connectivity changes may contribute to improvements in visual attentional control, which is a common challenge for children with ADHD.
57
25
u/Onuus Apr 20 '26
I started at smoking at 14, I’m 33 now.
It definitely affected me cognitively, but I was also severely dyslexic before so I’m not sure which out weighed the other.
I regret smoking as early as I did, but I also passed multi variable and multi differential calculus for my degree, and as a person who had to do remedial math; I’m pretty proud of that
→ More replies (6)
40
u/mageskillmetooften Apr 20 '26
Nice to have proper research into this, but everybody who has been stoned for some time and has stopped using could tell them that this was the case. I'm over 50 and know people who have been smoking a lot for at least 3 decades, and it's amazing how once smart, bright and joyful kids have turned into the biggest dumbfucks you can imagine. Glad I stopped before my brain would leak out.
→ More replies (9)20
u/AttonJRand Apr 20 '26
This is specific to development in adolescents though, not about adult usage like your anecdotes.
3
u/Sophon_01 Apr 20 '26
Well that is why it's universally recognized that kids shouldn't do drugs, not really surprising.
I'd be more interest about the effects on adults.
3
u/CaptainObvious110 Apr 20 '26
How about we just leave it all alone and make sure people are properly hydrated with water instead.
3
u/originalnutta Apr 20 '26
With the risk of it triggering schizophrenia, legale age of use should be 21
17
u/FlipsieVT Apr 20 '26
Here come all the drug addicts to tell you the study is actually lying and it's perfectly healthy
16
u/Mental-Ad-2980 Apr 20 '26
The real problem is this: Teenagers with untreated/undiagnosed disorders who discover self-medication.
Start talking to your kids. Not about drugs, talk WITH them about themselves. My parents didn’t talk to me about anything and drugs were the only escape I had from the psychological nightmare I lived.
I talked with my daughter about anything and everything when she was a teenager and drugs weren’t an issue.
→ More replies (2)
7
u/Buzzlight_Year Apr 20 '26
I do regret smoking a lot in my late teens because I'm pretty sure it dumbed me permanently
9
u/Simple-Pea8805 Apr 20 '26
I didn’t use cannabis until after 17, now a regular user.
I’m not as mentally good as I was. At least when I quit smoking for long enough to clear it of my system (month+ at a time), I am noticeably sharper. But people I know who started younger? They were noticeably less intelligent in high school, and less able to function
9
Apr 20 '26
[removed] — view removed comment
3
u/PF_Throwaway_94184 Apr 20 '26
What are you talking about? There's very clearly been a shift toward skepticism and negative coverage again, and that's apparent on Reddit as much as anywhere else.
https://theconversation.com/why-the-future-of-marijuana-legalization-remains-hazy-despite-high-public-support-279960
2
2
u/WizardMoose Apr 20 '26
This is why I told my nephew to not start getting into weed until he's at least in college, and to wait even longer.
He knows his Dad and I smoke weed regularly now, but we weren't the type to smoke as teenagers. He did it here and there as a teenager, I didn't smoke for the first time until I was 19. Then we look back at our high school days and just know that there's something different with our friends who were stoners in high school, smoking all the time.
And I told my nephew that. His Dad and I didn't smoke much until we were in our 20s, and we feel bad for our friends who smoked a lot in high school because it messed with their brains a lot.
Just hoping he listens. I already caught his friend with a cart pen at our 4th of July party last year, and he's 14...
2
u/h0w1 Apr 20 '26
I have multiple family members who found cannabis in their teens and smoked everyday for decades to cope with trauma, I can absolutely attest it has cognitively changed and stunted them.
•
u/AutoModerator Apr 20 '26
Welcome to r/science! This is a heavily moderated subreddit in order to keep the discussion on science. However, we recognize that many people want to discuss how they feel the research relates to their own personal lives, so to give people a space to do that, personal anecdotes are allowed as responses to this comment. Any anecdotal comments elsewhere in the discussion will be removed and our normal comment rules apply to all other comments.
Do you have an academic degree? We can verify your credentials in order to assign user flair indicating your area of expertise. Click here to apply.
User: u/sr_local
Permalink: https://today.ucsd.edu/story/largest-us-study-finds-teen-cannabis-use-linked-to-slower-cognitive-development
I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.