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Lead exposure in last century shrunk IQ scores of half of Americans: study

today.duke.edu

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Re: Lead exposure in last century shrunk IQ scores of half of Americans: study

#211

Post by legitster »

arcticbull wrote: post #147
legitster wrote: post #136

Earlier quoted context omitted.

The study in the linked article found that lead reduced the IQ of exposed Americans 3-6 IQ points. A New Zealand study found that persistent cannabis users had a 6-8 point decline, even if they had given up cannabis : https://www.pnas.org/doi/abs/10.1073/pnas.1206820109 Here's a meta review that found a 2 IQ point drop across a wider range of usage types: https://www.cambridge.org/core/journals/psychological-medici..…

That's not actually what the study found. Further, cessation of cannabis use did not fully restore neuropsychological functioning *among adolescent-onset cannabis users*. They did not find a 6-8 point decline for folks who gave up cannabis if they started later in life. In fact they found no decline in IQ whatsoever for folks who started later in life - both when using it and after stopping. In contrast, within-perso…

I don't think my summary was unfair. I was only asked if there was evidence for persistent effects. There clearly is, even if just for adolescents.

It's also important to point out that for the adult-onset group they only looked at 1 year back. This doesn't preclude the possibility that longer periods as an adult find different results.

Re: Lead exposure in last century shrunk IQ scores of half of Americans: study

#212

Post by rayiner »

legitster wrote: post #61

I have a strong worries that our current generation will have a similar huge reckoning with marijuana. We are already seeing studies that show regular marijuana use is correlated with permanent decreases in intelligence, memory loss, motivation, and mental health. And anecdotally, this seems very apparent in my peer group. And Americans are using copious amounts of the stuff right now, and younger than ever before. I…

I’m against legalization. I thought it was just going to be a humane alternative to putting people in jail. But instead we’ve just broken down the social norm against drug use. Parts of DC now smell strongly of weed during the middle of the day.

Re: Lead exposure in last century shrunk IQ scores of half of Americans: study

#214

Post by rayiner »

KennyBlanken wrote: post #127
WhompingWindows wrote: post #103

Earlier quoted context omitted.

Marijuana needs to be reclassified off of Schedule I Status in the USA, so it can be more thoroughly studied. Schedule I category shouldn't include recreational drugs like marijuana, which has no overdose possibility and has limited withdrawal side-effects. This wrong classification, going back to ignorant viewpoints of the early-mid 1900's, has heavily limited our scientific understanding of marijuana's effects on h…

> This wrong classification, going back to ignorant viewpoints of the early-mid 1900's It "goes back" to Nixon needing a tool to criminalize the anti-war and racial justice movement. https://www.cnn.com/2016/03/23/politics/john-ehrlichman-rich... By the time Nixon came out with that policy, multiple commissions around the world had concluded that pot was largely harmless and should be decriminalized. People in his ow…

Okay so explain all the other countries with harsh drug laws that don’t have Nixon or minorities to oppress? Japan, Singapore, Sweden, etc.

Re: Lead exposure in last century shrunk IQ scores of half of Americans: study

#215

Post by zelon88 »

shagmin wrote: post #201
legitster wrote: post #61

I have a strong worries that our current generation will have a similar huge reckoning with marijuana. We are already seeing studies that show regular marijuana use is correlated with permanent decreases in intelligence, memory loss, motivation, and mental health. And anecdotally, this seems very apparent in my peer group. And Americans are using copious amounts of the stuff right now, and younger than ever before. I…

According to [0] peak marijuana usage was in the 70s. I don't think with a smaller/more stable subset of the population partaking there's going to be many more people saying "we should have known better" than there currently are. https://www.mlive.com/resizer/G7WZuDwdu5D2eCujzIi_RYGWYkc=/7...

I wasn't there in the 70s, but from what I understand potency of the 70s wasn't nearly what it is today. I have no source for this, but I've been in countless circles with long time smokers who all correlate the same story; that modern day mids was literally the best quality Marijuana you could find in the 70s. So that's probably about 10% THC compared to 30% THC which is not uncommon today.

Re: Lead exposure in last century shrunk IQ scores of half of Americans: study

#216

Post by eloff »

legitster wrote: post #61

I have a strong worries that our current generation will have a similar huge reckoning with marijuana. We are already seeing studies that show regular marijuana use is correlated with permanent decreases in intelligence, memory loss, motivation, and mental health. And anecdotally, this seems very apparent in my peer group. And Americans are using copious amounts of the stuff right now, and younger than ever before. I…

To be fair there are also studies showing alcohol has similar effects on the brain. I saw one just yesterday:

"A large study of more than 36,000 high-quality MRI brain scans has found that drinking four units of alcohol a day – two beers, or two glasses of wine – causes structural damage and brain volume loss equivalent to 10 years of aging."

https://www.nature.com/articles/s41467-022-28735-5

I always said I would never smoke marijuana because my brain is my biggest asset and I wouldn't want to do anything to decrease its value to me. Now it looks like I need to take a good hard look at my alcohol consumption. I just can't square it with my values anymore.

Re: Lead exposure in last century shrunk IQ scores of half of Americans: study

#217

Post by schrectacular »

version_five wrote: post #180
Scalestein wrote: post #110

Earlier quoted context omitted.

I agree 100% with the potency concerns. Many of the studies showing negative impact were using standards like "10 joints a day" which was easy to dismiss as that was an unreasonable amount of weed for most people. Now with wax, tinctures and 20%+ THC strains becoming the normal it seems really easy for many people to be hitting those previously unrealistic dosages.

I'm curious, because I have not heard of wax or tinctures, do you think those are things that more people will use, vs people who would have used some hard drugs anyway? What I mean is, there will always be some hard drug users, now from the discussion I understand some "hard" THC products exist, will this result in any kind of demographic change like the OP worried about, or is it just a new drug of abuse? Just beca…

They are very common - "vape cartridges" are the preferred intake mechanism for a lot of people because it's much more discrete (almost no smell, can pass for normal vaping) and convenient (small size). And those cartridges can be upwards of 90% THC.

Re: Lead exposure in last century shrunk IQ scores of half of Americans: study

#218

Post by wonderwonder »

version_five wrote: post #180
Scalestein wrote: post #110

Earlier quoted context omitted.

I agree 100% with the potency concerns. Many of the studies showing negative impact were using standards like "10 joints a day" which was easy to dismiss as that was an unreasonable amount of weed for most people. Now with wax, tinctures and 20%+ THC strains becoming the normal it seems really easy for many people to be hitting those previously unrealistic dosages.

I'm curious, because I have not heard of wax or tinctures, do you think those are things that more people will use, vs people who would have used some hard drugs anyway? What I mean is, there will always be some hard drug users, now from the discussion I understand some "hard" THC products exist, will this result in any kind of demographic change like the OP worried about, or is it just a new drug of abuse? Just beca…

They are pretty heavily in use and available at most locations that legally sell marijuana. Estimate they are 15 to 20% of sales, perhaps more. Even common flower now is 20% thc.

Re: Lead exposure in last century shrunk IQ scores of half of Americans: study

#219

Post by ifyoubuildit »

mountainriver wrote: post #186
tlss wrote: post #66

Earlier quoted context omitted.

Recreational marijuana and JUUL is very much a millenial/gen Z hobby, and it is being pushed with a fervor that glosses over serious studies any potential health risks. IMO weed will be in 50 years where "big tobacco" is right now.

Not a chance, maybe smoking marijuana, but not edibles. I know plenty of people that have done them their entire lives and are in great shape

That sounds a lot like "my grandmother smoked 2 packs a day and lived til she was 99."

I think the whole point is that it hasn't been studied yet, so we can't say definitively if its safe or not.

Re: Lead exposure in last century shrunk IQ scores of half of Americans: study

#220

Post by quercetumMons »

teknopaul wrote: post #200

Independent of the effect of lead on intelligence isn't it impossible to reduce the IQ of half the population because IQ is a comparative calculation across that population. Ie as intelligence goes down the definition of 100 IQ points changes? https://en.m.wikipedia.org/wiki/Intelligence_quotient

Think of it from the individual-up. Even if the half of people with affected IQs were spread proportionally throughout the IQ bell curve, they'd have lower IQs than they did before. The other half would raise just as much as the affected half lowered, but the affected half still have lower IQs.
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