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Study questions whether pot makes teens stupid

By Malcolm Ritter

AP Science Writer

LAST UPDATED: 02:39 a.m. HST, Jan 15, 2013

NEW YORK >> A new analysis is challenging a report that suggests regular marijuana smoking during the teen years can lead to a long-term drop in IQ. The analysis says the statistical analysis behind that conclusion is flawed.

The original study, reported last August, included more than 1,000 people who'd been born in the town of Dunedin, New Zealand. Their IQ was tested at ages 13 and 38, and they were asked about marijuana use periodically between those ages.

Researchers at Duke University and elsewhere found that participants who'd reported becoming dependent on pot by age 18 showed a drop in IQ score between ages 13 and 38. The findings suggest pot is harmful to the adolescent brain, the researchers said.

Not so fast, says an analysis published online Monday by the Proceedings of the National Academy of Sciences.

Ole Rogeberg of the Ragnar Frisch Center for Economic Research in Oslo, says the IQ trend might have nothing to do with pot. Rather, it may have emerged from differences among the study participants in socioeconomic status, or SES, which involves factors like income, education and occupation, he says.

He based his paper on a computer simulation. It traced what would happen to IQ scores over time if they were affected by differences in SES in ways suggested by other research, but not by smoking marijuana. He found patterns that looked just like what the Duke study found.

In an interview, Rogeberg said he's not claiming that his alternative explanation is definitely right, just that the methods and evidence in the original study aren't enough to rule it out. He suggested further analyses the researchers could do.

The Duke scientists, who learned of Rogeberg's analysis late last week, say they conducted new statistical tests to assess his proposed explanation. Their verdict: It's wrong. Rogeberg says they need to do still more work to truly rule it out.

Experts unconnected to the two papers said the Rogeberg paper doesn't overturn the original study. It "raises some interesting points and possibilities," but provides "speculation" rather than new data based on real people, said Dr. Duncan Clark, who studies alcohol and drug use in adolescents at the University of Pittsburgh.

Dr. Nora Volkow, director of the National Institute on Drug Abuse, said observational studies of people like the Duke work can't definitively demonstrate that marijuana cause irreversible effects on the brain. In an email, she said Rogeberg's paper "looks sound" but doesn't prove that his alternative explanation is correct.



Journal: http://pnas.org

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serious wrote:
If true, most of our politicians must have used it.
on January 14,2013 | 01:59PM
OldDiver wrote:
Explains the Fox News viewer.
on January 14,2013 | 04:16PM
Waterman2 wrote:
Did that study...privately funded.....the answer is "yes" . Why do you think they call it Paka "lolo" ? Duhh! Dude.
on January 14,2013 | 02:28PM
Waterman2 wrote:
In fact, why do you think Obama is having so many problems ? Duhhh. Dude.
on January 14,2013 | 02:29PM
HawaiiCheeseBall wrote:
Yep he is having so many problems the people of these United States of America elected him to a second term in the White House!
on January 14,2013 | 03:14PM
false wrote:
Which just goes to prove that Berry ain't the only dude smoked pot.
on January 14,2013 | 09:58PM
BlueDolphin53 wrote:
Funny all this back and forth on pot, but I don't know of one person I know who smokes pot who I would consider a "responsible" person. Nice person maybe, but not responsible, as in someone I would trust with something very important to do.
on January 14,2013 | 02:31PM
Fred01 wrote:
I guess you don't know very many people.
on January 14,2013 | 02:43PM
loio wrote:
fred01's correct
on January 14,2013 | 04:02PM
sailfish1 wrote:
More likely he is too smart to associate with many people who smoke pot.
on January 14,2013 | 10:04PM
Skyler wrote:
Actually... having smoked it when I was 17, I"d say it definitely impaired my judgement at the time. How many can say with a straight face that it doesn't? No one, otherwise they wouldn't smoke it to begin with. Getting "high" is not without consequence.
on January 14,2013 | 03:09PM
HawaiiCheeseBall wrote:
Does smoking pot make you stupid, or do stupid people smoke pot. I guess only one way to find out.....
on January 14,2013 | 03:14PM
jusjoking wrote:
yah well, that's just your opinion cause well, you know, cause, i neva you know, huh what?
on January 14,2013 | 04:23PM
islandsun wrote:
No, they are natually stupid like their parents....
on January 14,2013 | 04:53PM
The_Dude_Abides wrote:
Reading this article: "Study questions whether pot makes teens stupid"...actually makes teens stupid.
on January 14,2013 | 04:54PM
SueH wrote:
Don't blame the pot....Teens are just naturally stupid.
on January 14,2013 | 07:55PM
sailfish1 wrote:
Only stupid people smoke pot or take any other illegal drugs. If the pot lowers their IQ, I guess they get even more stupid.
on January 14,2013 | 10:01PM
TLehel wrote:
Does smoking pot lower your IQ? To some small degree I bet it does. I mean when you're high your senses are so much different, your short term memory goes down the toilet for most people, and many other factors based on the individual. What I mean by that is Marijuana affects everyone differently. So any possible long term effects can vary. If there was one long term effect that weed causes, though, I'd say it's short term memory. All in all, weed is a natural herb that will mess with your life only if you allow it to. It's not addictive, it's no harm to your lungs in comparison to cigarettes, it doesn't leave you with any long term physical impairments and it's one of the few drugs that actually keeps you from doing retarded (dangerous) things. If weed does drop IQ, it's barely.
on January 15,2013 | 10:43AM
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