Posted on 08/28/2012 8:38:47 AM PDT by fishtank
Study: Adolescent marijuana use leaves lasting mental deficits August 27, 2012 in Psychology & Psychiatry The persistent, dependent use of marijuana before age 18 has been shown to cause lasting harm to a person's intelligence, attention and memory, according to an international research team. Among a long-range study cohort of more than 1,000 New Zealanders, individuals who started using cannabis in adolescence and used it for years afterward showed an average decline in IQ of 8 points when their age 13 and age 38 IQ tests were compared. Quitting pot did not appear to reverse the loss either, said lead researcher Madeline Meier, a post-doctoral researcher at Duke University.
The results appear online Aug. 27 in PNAS. The key variable in this is the age of onset for marijuana use and the brain's development, Meier said. Study subjects who didn't take up pot until they were adults with fully-formed brains did not show similar mental declines. Before age 18, however, the brain is still being organized and remodeled to become more efficient, she said, and may be more vulnerable to damage from drugs.
"Marijuana is not harmless, particularly for adolescents," said Meier, who produced this finding from the long term Dunedin Multidisciplinary Health and Development Study. The study has followed a group of 1,037 children born in 1972-73 in Dunedin, New Zealand from birth to age 38 and is led by Terrie Moffitt and Avshalom Caspi, psychologists who hold dual appointments at Duke and the Institute of Psychiatry at King's College London.
About 5 percent of the study group were considered marijuana-dependent, or were using more than once a week before age 18. A dependent user is one who keeps using despite significant health, social or family problems. At age 38, all of the study participants were given a battery of psychological tests to assess memory, processing speed, reasoning and visual processing.
The people who used pot persistently as teens scored significantly worse on most of the tests. Friends and relatives routinely interviewed as part of the study were more likely to report that the persistent cannabis users had attention and memory problems such as losing focus and forgetting to do tasks.
The decline in IQ among persistent cannabis users could not be explained by alcohol or other drug use or by having less education, Moffitt said. While 8 IQ points may not sound like a lot on a scale where 100 is the mean, a loss from an IQ of 100 to 92 represents a drop from being in the 50th percentile to being in the 29th, Meier said. Higher IQ correlates with higher education and income, better health and a longer life, she said. "Somebody who loses 8 IQ points as an adolescent may be disadvantaged compared to their same-age peers for years to come," Meier said. Laurence Steinberg, a Temple University psychologist who was not involved in the research, said this study is among the first to distinguish between cognitive problems the person might have had before taking up marijuana, and those that were apparently caused by the drug.
This is consistent with what has been found in animal studies, Steinberg added, but it has been difficult to measure in humans. Animal studies involving nicotine, alcohol and cocaine have shown that chronic exposures before the brain is fully developed can lead to more dependence and long-term changes in the brain. "This study points to adolescence as a time of heightened vulnerability," Steinberg said. "The findings are pretty clear that it is not simply chronic use that causes deficits, but chronic use with adolescent onset."
What isn't possible to know from this study is what a safer age for persistent use might be, or what dosage level causes the damage, Meier said. After many years of decline among US teens, daily marijuana use has been seen to increase slightly in the last few years, she added. Last year, for the first time, US teens were more likely to be smoking pot than tobacco. "The simple message is that substance use is not healthy for kids," Avshalom Caspi said via email from London. "That's true for tobacco, alcohol, and apparently for cannabis."
More information: "Persistent Cannabis Users Show Neuropsychological Decline From Childhood to Midlife," Madeline H. Meier, Avshalom Caspi, et al. Proceedings of the National Academy of Sciences, Online Early Edition, Monday, Aug. 27, 2012.
Read more at: http://medicalxpress.com/news/2012-08-adolescent-pot-mental-deficits.html#jCp
“”Nobody who dislikes jail will be sharing with minors.”” (if it becomes legal, and ubiquitous, and grown everywhere)
Huh?
No contradiction - it's my observation that under current laws teens get pot almost exclusively through purchase, from people risking jail in exchange for profit. There would be no profit in the sharing scenario you presented.
Weird.
The scenario I described is one where pot is free, to almost free, and literally everywhere.
Teens will be rolling in the stuff.
Legalizing pot turns it into a common houseplant and yard shrubbery, it will be everywhere.
As it is now, when we find pot plants in our gardens and yards, we pull them out.
Thanks fishtank. In their defense, they weren’t all that bright in the first place.
This could be “Libtard TV, Radio, Print media, and WWW Leaves Lasting Cognitive Deficits”.
Still wrong - as I said, see http://en.wikipedia.org/wiki/Cannabis_cultivation for what's involved.
As it is now, when we find pot plants in our gardens and yards, we pull them out.
Try smoking some - I can guarantee you'll get no high.
Growing great pot is as easy as pie
Hmm ... on the one hand, a thoroughly footnoted article, and on the other hand, an unsupported claim ... which to believe?
Growing great pot is as easy as pie, easier than growing great tomatoes, that is why it is often grown in closets and spare bedrooms,
No, it's grown there because it's illegal. Do you never tire of saying foolish things?
and America is full of people in apartments and homes,and bare patches of ground, and teens know them.
Teens know people who have the space for home beer-brewing, too - that's not the same as having access to home brew.
By the way, your graphic makes no claim about "great pot" so it proves zip.
Growing pot is easy, that is why we have to pull up so many plants out of our yards and gardens. You just don’t seem to have ever grown any, or know anything about it.
People grow indoors for many reasons, one is that ‘why not?’, it is easy and convenient, it is year round, non-seasonal, accelerated growth, perfect conditions and temperatures, what’s not to like?
I have made home brew, and I have grown pot, pot is simple, home brew is hard, and with little yield.
I take it that you don’t garden, so you thought that wiki page looked complicated?
You also seem to think that every pot plant has to exceed the quality that fueled the 1960s.
Growing high quality pot is simple as pie to anyone that can grow tomatoes.
You carefully avoid saying whether you ever smoked any of that pot.
I take it that you don’t garden, so you thought that wiki page looked complicated?
It is; I invite interested readers to see for themselves.
I take it that you don’t garden, and that you have never grown pot then.
Growing pot is easy, it is a pretty, and sturdy plant, it produces a huge amount of the drug, and the drug has a long shelf life.
If it becomes legal, there won’t be taxes and controls over it. Pot will simply become ubiquitous, and free, and near free.
Will the store carry some taxed product in a nice package, sure, but only for the upscale and impulse buyers, gifts and hobbyists and gardeners who don’t even smoke, will take care of the rest, I don’t smoke, but I will grow the plant, I always regret having to throw them away and kill them.
Translation for those teens that are smokin......Doobies will make you dumb!
We grew tomatoes a few summers ago. With relatively little effort, we got good-tasting produce - whereas the pot you grew was useless for mind alteration.
and that you have never grown pot then.
Growing pot is easy [...] I don’t smoke
Growing ditchweed is easy; growing mind-altering pot is not, as I've shown with a thoroughly footnoted article.
Growing high quality pot
Make up your mind - are we talking about high quality pot, or not?
Good gosh does every thing have to be explained to you, the answer is both.
Decent weed fueled the 1960s and higher quality pot is easy to grow.
LOL, you don’t know about the pot we have grown.
You just keep throwing out things that you don’t know about.
A case of having a conclusion you want to reach, and forcing everything to fit that made up scenario.
I would be surprised if you have ever done any living among the serious drug culture, or communal living.
Back to the baseless claim I've rebutted with a thoroughly footnoted article.
Since you say you don't smoke, you don’t know about the pot you have grown. What I know from the thoroughly footnoted article I've linked is that mind-altering pot doesn't grow the way you've described your pot growing.
I would be surprised if you have ever done any living among the serious drug culture, or communal living.
I would be surprised if you could show any relevance of those matters to the questions we've been discussing. Dragging in red herrings to distract from a losing argument is another hallmark of the Drug Warrior.
Well good luck with your delusions, it doesn’t seem to occur
to you that someone may have decades of experience with that world, beginning in the wild and woolly 60s and communal living.
Grow your first pot plant, and see if you find it so demanding.
Well good luck with your delusions, it doesn’t seem to occur to you that someone may have decades of experience with that world, beginning in the wild and woolly 60s and communal living.
It doesn’t seem to occur to you that you have yet to demonstrate any relevance of these distractions.
It remains the case that the pot you grown has not been shown to be mind altering, and that you've offered no reason to doubt the thoroughly footnoted article I linked.
Grow your first pot plant, and see if you find it so demanding.
Now that you mention it, I did grow pot in college, in my closet - it didn't get me high. Thanks for the reminder!
Well the pot that was grown by my roommate in Southern California, right outside the front door was highly desired, and the growing was as easy as pie, the old man next door even admired the huge, beautiful plants, I forget what he was told about them.
You just haven’t had any experience with this stuff, or gardening, you read that wiki article about how to make the perfect pot plant, and it seems complex to you.
Read it again, potting soil, check, sunlight, check, water, check, some plant food, check, don’t let it freeze, check, pinching, flowering, tying it, all routine gardening, we do it all with our tomatoes, we sprout the seeds, start them indoors, plant them outside, we pinch them, stake them, tie them, that is how some of us have grown 16 foot tall tomato plants.
Sellers grow huge crops of pot all over the forests and mountains, with little effort, some water, some food, good climate. Growing pot in your closet is easier, if you read the pamphlet first.
Read your own wiki article, but give it a little thought while you read it, it doesn’t get into anything complicated, the same article can be written on tomatoes.
And their desires were fulfilled: they actually got high from this stuff?
pinching, flowering, tying it, all routine gardening, we do it all with our tomatoes
Never did any of those with the tomatoes I successfully grew - nor tried to prevent pollination, nor gradually increased the strength of the fertilizer. Certainly not an activity for everyone - least of all the sort of adolescent who wants to regularly smoke pot.
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