Cannabis makes you dumber according to studies in New Zealand

[MarcoM]

http://www.bbc.co.uk/news/health-19372456

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Young people who smoke cannabis run the risk of a significant and irreversible reduction in their IQ, research suggests.

The findings come from a study of around 1,000 people in New Zealand.

An international team found those who started using cannabis below the age of 18 - while their brains were still developing - suffered a drop in IQ.

A UK expert said the research might explain why people who use the drug often seem to under-achieve.

For more than 20 years researchers have followed the lives of a group of people from Dunedin in New Zealand.

They assessed them as children - before any of them had started using cannabis - and then re-interviewed them repeatedly, up to the age of 38.

Having taken into account other factors such as alcohol or tobacco dependency or other drug use, as well the number of years spent in education, they found that those who persistently used cannabis suffered a decline in their IQ.

The more that people smoked, the greater the loss in IQ.

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It is such a special study that I'm fairly confident that cannabis is safe for over-18 brains, but risky for under-18 brains”
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Professor Terrie Moffitt

Institute of Psychiatry, King's College London
The effect was most marked in those who started smoking cannabis as adolescents.

For example, researchers found that individuals who started using cannabis in adolescence and then carried on using it for years showed an average eight-point IQ decline.

Stopping or reducing cannabis use failed to fully restore the lost IQ.

The researchers, writing in the US journal Proceedings of the National Academy of Sciences, found that: "Persistent cannabis use over 20 years was associated with neuropsychological decline, and greater decline was evident for more persistent users."

"Collectively, these findings are consistent with speculation that cannabis use in adolescence, when the brain is undergoing critical development, may have neurotoxic effects."

One member of the team, Prof Terrie Moffitt of King's College London's Institute of Psychiatry, said this study could have a significant impact on our understanding of the dangers posed by cannabis use.

"This work took an amazing scientific effort. We followed almost 1,000 participants, we tested their mental abilities as kids before they ever tried cannabis, and we tested them again 25 years later after some participants became chronic users.

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“
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There are a lot of clinical and educational anecdotal reports that cannabis users tend to be less successful in their educational achievement, marriages and occupations”
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Professor Robin Murray

Instuitute of Psychiatry, King's College London
"Participants were frank about their substance abuse habits because they trust our confidentiality guarantee, and 96% of the original participants stuck with the study from 1972 to today.

"It is such a special study that I'm fairly confident that cannabis is safe for over-18 brains, but risky for under-18 brains."

Robin Murray, professor of psychiatric research, also at the King's College London Institute of Psychiatry but not involved in the study, said this was an impressive piece of research.

"The Dunedin sample is probably the most intensively studied cohort in the world and therefore the data are very good.

"Although one should never be convinced by a single study, I take the findings very seriously.

"There are a lot of clinical and educational anecdotal reports that cannabis users tend to be less successful in their educational achievement, marriages and occupations.

"It is of course part of folk-lore among young people that some heavy users of cannabis - my daughter callers them stoners - seem to gradually lose their abilities and end up achieving much less than one would have anticipated. This study provides one explanation as to why this might be the case.

"I suspect that the findings are true. If and when they are replicated then it will be very important and public education campaigns should be initiated to let people know the risks."

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So maybe cannabis is not so cool after all?

 

[Skython]

TL;DR... Just came in here to post a remark because it has something to do with New Zealand. And its large amount of dumb people.

Of course we would know in NZ, we have many losers willing to take tests and be studied if they are given free cannabis.

 

[lbsf1]

IF YOU ARE UNDER 18.

According to an actual professor, Professor Terrie Moffitt of the Institute of Psychiatry at King's College London, "It is such a special study that I'm fairly confident that cannabis is safe for over-18 brains, but risky for under-18 brains".

Of course we would know in NZ, we have many losers willing to take tests and be studied if they are given free cannabis.

I would, lol. I know many, many stoners and when all of them stop taking it around exam times they are just like everyone else, if you stop smoking it it stops effecting you. (unless you have underlying mental health problems which cannabis could bring up.)

 

[Schwartz]

So maybe cannabis is not so cool after all?

Of course it's cool! "Dumb" is the new "smart." See MTV.

 

[Tesla]

8 IQ points doesn't seem like a noticeable amount to me, nor do I think that testing IQ is the best way of going about testing what effects cannabis has on youths. Interesting results nonetheless.

 

[Grayfox]

If you smoke cannabis you are stupid do start with so making a stupid person more stupid does not warrant much.

 

[MarcoM]

Apperently it's true:
http://frontpage.fok.nl/nieuws/559957/1/1/100/dode-ossenaar-geelektrocuteerd-in-wietkwekerij.html

Dead man in Oss (The Netherlands) is electrocuted in his weed plantation. Sad thing is that he died after the reanimation.

 

[Ibonibo]

Yeah, I started smoking pot very early. Smoked during my exams in both high school and uni.
Hadn't noticed I was dumber than before. (managed to get better points with less learing than the majority, and no I am not overly smart (not that I know of))
I stopped smoking some time back, hadn't had a boost in my IQ either.
Pot is such a subjective effect drug that it differs to much in such studies.
I bet there are studies (or you could make them) showing the increase in creativity, concentration on a subject, increase in interest on a subject, when smoking.

All those studies are meh to me as long as I don't know all the background of the studies. Studies can be (especially the conclusion) can be altered to your likening, and state funded studies will always show the negatives.

About the study: It's nice to have a study over such a time period, but since then, the Iq test have changed and the quality of pot has changed. HAve they accounted those variables?

 

[Tesla]

If you smoke cannabis you are stupid do start with so making a stupid person more stupid does not warrant much.

You really think that huh? Steve Jobs, Carl Sagan, Richard Branson, George Washington and Steve King have all taken cannabis.

 

[MarcoM]

I stopped smoking some time back, hadn't had a boost in my IQ either.

Once the damage is done, the IQ will not improve when you stop

All those studies are meh to me as long as I don't know all the background of the studies. Studies can be (especially the conclusion) can be altered to your likening, and state funded studies will always show the negatives.

True to that, but that can also be said about studies that show the positive effects.

 

[88FoxBodyFan]

Another "study" of government issued, made up "statistics."

Nice try.

 

[NLxAROSA]

You really think that huh? Steve Jobs, Carl Sagan, Richard Branson, George Washington and Steve King have all taken cannabis.

And there's probably a billion or more cannabis users that accomplished absolutely nothing. Either statement doesn't mean anything.

True to that, but that can also be said about studies that show the positive effects.

I don't think it should come as a surprise to anyone that if you throw alcohol, cannabis, cocaine or any other drug/chemical at a still developing brain, that it may have impact on the end result.

 

[MarcoM]

I don't think it should come as a surprise to anyone that if you throw alcohol, cannabis, cocaine or any other drug/chemical at a still developing brain, that it may have impact on the end result.

Hence my advise: use it sparsely.

 

[Zenith]

For every study that shows that even smelling weed will give STD's to starving children in Africa, there's another that shows that ingesting large amounts of weed will bring your childhood dog back to life.

This applies to drugs, coffee, walking, cars, and exhalation.

One thing I have learned over the years is never to trust a study, especially one that you were never involved in.

 

[Danoff]

Isn't this general common sense? All of my experience is anecdotal, but all of my experience suggests that this is the case - weed makes you dumber. I think probably directly (by altering your brain) and indirectly (by causing you not to exercise your brain).

 

[MarcoM]

It is, but now it's backed up by a study.

 

[Diogo]

I should use that on my english classes , that way I can be at same level as my class.

 

[Keef]

Most of my friends smoke pot a few times a week and they're all fairly successful college students, either already graduated from 2 and 4 year schools with new jobs or are about to graduate. In my lower-middle class suburban public school and college experience, weed has virtually no effect on one's intelligence, ability, or social life.

There were pot smokers who were lazy underachievers who seemed really dumb, but that wasn't from the pot. That's because they were raised by lazy, underachieving, dumb parents to be lazy, underachieving, and dumb. Poor people live in a rut caused in large part by their own attitude toward the rest of the world and it takes a little something extra to rise out of that. They refuse because they don't care, not because they smoke pot. They spend what little money they have on pot because they were already dumb to begin with, not because the pot made them dumb.

The article doesn't say a damn thing about the subjects' parents or how they were raised or their general demeanor. There are way to many factors related to intelligence, motivation, and achievement to narrow it down to smoking weed. There is just as much evidence showing that weed makes you smart and successful as there is showing it makes you dumb and lazy.

I will concede one point: The only dumb thing about weed is that it's expensive. But cigarettes are too and they don't even make your shoe laces funny.

 

[photonrider]

Dumb = Duh? What?
Dumb for what?
Rocket Science? Marksmanship? Tea-tasting? Pole-Dancing? Tone-arranging?

The Validity of individual I.Q. tests (never mind the differences in culture and economics across the world) has always been a debate.

However, it's well known (researched, documented, and archived at many scientific and scholarly institutions I would think) that substances such as caffiene, alcohol, and weed do alter the structure of the brain (and therefore the way it functions).
Add that factor to a young 'developing' (as in physically) brain, and there should be no doubt that Delta - 9 will more than make you fly. Be kind to your brain - you need all of it as you get older in a society that is dominantly anti-Luddite.

Though, as one gets older, priorities change. Sometimes the I.Q. required as per those tests, is only a nuisance in the pursuit of happiness.

Cheers,
Harry.

 

[Pupik]

I think many of you need to understand the differences between an occasional pot smoker and someone who constantly smokes the stuff for many years. One toke does not equal stupid. The person who does it several times a day...possibly; a few famous individuals who have enjoyed it doesn't negate those who can't make a decision in life without inhaling.

 

[Ibonibo]

^ I beg some to read the study which I overflew in the afternoon.

A few points :

Occasional smokers: 1% less in IQ
"hardcore" smokers : 6% less
Average person who doesn't smoke : 1% more

So it still is very marginal, I think a person with 120IQ will not turn dumb with 118.8.
Also increase or decrease in IQ, it depends what you do. As you were told as a kid, the brain is like a muscle, the more you practice, the better you get.

Even if you are mental dead with an IQ of 20, you will not get more dumb with it.

I honestly think watching the Kardashians once a week is more damaging that smoking pot.

Study done over 40 years in NZ.
40years, lets say they started with 16 year old they would now be 56.
That suggests that many haved stopped probably early 20's or somewhen after.
IQ test have drasticlly changed in 40 years (logic is just one of many factors).
What was the cultural background of the subjects, their living situation, other mind altering substances,....



Also did you know that these "studies" are 99% assumptions made on correlation (best case scenario) on statistic grounds. It is not scientificly proven, it's an assumption that may be rejected by the next so called "study".
That's why studies constantly contradicts themselves, like with red wine, eggs,....

For me that classifies this whole shabang as govermental propaganda

 

[MatskiMonk]

Also did you know that these "studies" are 99% assumptions made on correlation (best case scenario) on statistic grounds. It is not scientificly proven, it's an assumption that may be rejected by the next so called "study".
That's why studies constantly contradicts themselves, like with red wine, eggs,....

For me that classifies this whole shabang as govermental propaganda

Okay, so there is an increased probability of a reduced IQ if you smoke POT under the age of 18. Better?

Seriously, just because it's statistics it doesn't make it propoganda. Statistically speaking, drinking 10 pints and then driving home from the Pub makes you more likely to have a crash - it does not make it a scientific fact that you will crash, but a drinker would have to be pretty stupid to call the reasoning behind drink drive laws 'propoganda' in order to negate his crime.

Personally whilst I don't really condone 'drug' use for recreational purposes, as someone that drinks excessive amounts of alcohol, I do get the attraction of mind-altering substances, but I've accepted that it has its risks and drawbacks and I accept them, it seems that every time an article suggests that cannabis is bad for you, all the pot-heads get really defensive! Maybe it's just the paranoia?!

 

[Chiochan]

If you are stupid and smoke pot, you will still be stupid. If you are smart and smoke pot, you will still be smart. Don't smoke pot if you are under 18 or you will be stupid. This is not new news.

 

[Ibonibo]

Okay, so there is an increased probability of a reduced IQ if you smoke POT under the age of 18. Better?

Seriously, just because it's statistics it doesn't make it propoganda. Statistically speaking, drinking 10 pints and then driving home from the Pub makes you more likely to have a crash - it does not make it a scientific fact that you will crash, but a drinker would have to be pretty stupid to call the reasoning behind drink drive laws 'propoganda' in order to negate his crime.

I never said that. I said that this articles (I read multiple ones, from different countries) are, not the statistic behind it. Raw data statistics are all fine. It's what happens after that is mind boggling sometimes.

If the decrease is one percent, it is neglagable as it doesn't make you dumb. No need for sensational headlines like that

Make IQ test after not having slept, you will have a decrease too, but you are not stupid for that, though you could put it like that.

Read the study and it shows immediatly that it is over hyped

 

[MarcoM]

Personally whilst I don't really condone 'drug' use for recreational purposes, as someone that drinks excessive amounts of alcohol, I do get the attraction of mind-altering substances, but I've accepted that it has its risks and drawbacks and I accept them, it seems that every time an article suggests that cannabis is bad for you, all the pot-heads get really defensive! Maybe it's just the paranoia?!

I knew the defensive reactions would come when I posted the article. Perhaps it also has to do with the fact that in many countries it is illegal and that they (pot-heads) want it legalized.

Personally I never smoked weed, even though it was/is very easy for me to obtaion. I don't think having a few times a year is bad. But I do see some young folks around the coffeeshops in my area spending large ammounts of time and money on weed. That will affect their future.

 

[MatskiMonk]

My best friend smoked cannabis for years (just socially) when he was in his early 20's, then when at university he started to get quite dependent as it helped with the stress, he recognised this and stopped - now he does it maybe once every few months. For him the worst side effect was the paranoia.. but anyway, my point is... I know cannabis doesn't make you dumb, and if it does, probably no more than numerous other things... but just because that's true, it doesn't mean that cannabis doesn't have a negative effect on your intelligence - and if that is a negative side effect, then users should be made aware so their choice to do it is an educated one.

 

[Keef]

...The person who does it several times a day...possibly; a few famous individuals who have enjoyed it doesn't negate those who can't make a decision in life without inhaling.

Possibly, yes, but no studies have ever supported it and this one sure as hell doesn't.

A few famous individuals who are clean doesn't negate those who can't make a decision in life despite being clean. I wasn't talking specifically about famous people, I was talking about everyday people who smoke regularly yet are totally normal and have families and homes, etc. Most people. My ex-neighbors smoke and they're into fitness, jogging and hiking, the wife is a dog trainer and the husband is a salesman for a local machining company. One of my aunts works for a local court system while her husband is a construction contractor. An uncle is a professor at OU and has been smoking regularly for about 50 years now. I don't live in a fancy neighborhood, where almost everybody but my parents have moved out as their situations have improved over the years. The nicest house might be worth $150k on a good day, and within a mile you can find hoodrats and Section 8 apartments, and we all went to the same average high public high school.

I'm just not seeing it. Because I literally know nobody who has failed in life because of pot smoking I have to go out of my way to find anybody in that situation, and when I do find them I realize that they didn't fail because they started smoking at 14, they failed because they were born into failure by parents who had failed long ago. To say that people who fail smoke pot is wholly true, but to say that people fail because they smoke pot is ridiculous. The most profound negative effect that weed has on a person is a tightening budget, but you can't knock them for that when there are other people out there who do equally unproductive things like drink at a bar, devour Steam sales, or collect Hotwheels.

 

[shmogt]

Haha best study. If you are under 18 you are in high school. Everyone knows high school is boring so to pass the time kids will go smoke weed than go to class. Cannabis in all the studies I have seen show that it triggers the parts of the brain that makes you forget. So to put this in perspective you have under 18yr old kids who already don't care by smoking weed, than they go to class and not pay attention, learn nothing than go home. Whatever they did learn that day the Cannabis made them forget anyway. Not sure if you can really say cannabis makes you lose IQ or just the lack of learning that is responsible.

 

[MatskiMonk]

The most profound negative effect that weed has on a person is a tightening budget

So the biggest reason why you aren't completely toasted all of the time is that you can't afford it? (I'm assuming you are not completely toasted all of the time!)

 

[Danoff]

I'm just not seeing it. Because I literally know nobody who has failed in life because of pot smoking

That's kindof a high threshold don't you think? I'm talking about noticing a change in an individual for the slightly dumber, not a genius suddenly becoming retard.

I'm also not saying it can't be an excellent recreational drug (never tried it, but it seems like it can work), just like any other recreational drug (alcohol, tobacco, etc.). But in my experience, it knocks a few percent off of someone's intellectual ability. In engineering grad school I knew a guy who smoked fairly often, and he just... approached things in the way pot smokers generally approach things - which is to say that it's not the most conducive to learning or intellectual stimulation. He was in engineering grad school mind you, bright guy just to be there - and weed didn't cause him to flunk out. I do think it held him back just a little.