Pubdate: Tue, 11 Sep 2012
Source: Daily Nebraskan (U of NE, NE Edu)
Copyright: 2012 Daily Nebraskan
Contact:  http://www.dailynebraskan.com/
Details: http://www.mapinc.org/media/1176
Author: Maren Westra

STUDY: LONG-TERM MARIJUANA USE DECREASES IQ OF YOUTH -

Teenagers hear a lot of rumors. And one of them -- marijuana use is 
not harmful to overall health -- has just been disproven, according 
to a study published Aug. 27 in the Proceedings of the National 
Academy of Sciences.

The study followed about 1,000 people born in a one-year span between 
1972 and 1973 in Dunedin, New Zealand. The results suggest those who 
begin using marijuana as adolescents and into adulthood experience a 
long-term decrease in IQ.

Researchers tested the IQ of the participants at 13 years old, an age 
at which significant marijuana use was considered unlikely. Then, at 
age 18, participants returned for a survey on their use of the drug. 
The subjects were interviewed four more times over the next 20 years, 
and those who displayed marijuana dependence before the age of 18 
showed an IQ drop by age 38. Those who began using marijuana after 
the age of 18 did not show an IQ drop.

The younger the participant began using the drug, the more 
significant the decrease in IQ. Those who smoked regularly showed an 
average IQ drop of as much as eight points, and results indicated 
quitting use did not lead to recovery of the IQ points. Those who did 
not smoke gained an average of one IQ point.

Allison Dering-Anderson, a pharmacist at the University of Nebraska 
Medical Center College of Pharmacy, has studied the effects of 
marijuana and read extensive literature regarding studies of the drug.

She said the results of the study aren't surprising because any time 
a developing brain is exposed to something that affects cognition, it 
can be expected to suffer.

She also said she's curious as to why the study didn't report on 
other drugs, such as LSD, heroin, cocaine or methamphetamine.

Jeffrey Baldwin, a substance abuse specialist at UNMC, said the brain 
fully matures around age 25, so excessive marijuana use at a young 
age can contribute to addiction and developmental delays.

"I would caution people about using marijuana at any age but 
especially younger people," he said.

However, he said he isn't sure if the study is accurate. He said he 
suspects participants who admitted to smoking significant amounts of 
marijuana would answer fewer questions on an IQ test correctly not 
because their IQ was affected long-term by the drug, but because they 
were under its influence while taking the test.

He said he believes marijuana contributes more to amotivational 
syndrome, which describes a loss of interest in social and academic 
endeavors, than permanent brain damage.

The study also showed a number of participants developed a dependency 
on marijuana, meaning they continued to use it even after legal, 
social or health problems arose because of it.

If teenagers don't think marijuana is addictive, "they're mistaken," 
Baldwin said. "High level chronic marijuana meets the DSM IV-TR 
criteria for addiction."

DSM IV-TR is the American Psychiatric Association's "The Diagnostic 
and Statistical Manual of Mental Disorders" fourth-edition text 
revision and is used to classify mental disorders.

Both Dering-Anderson and Baldwin said they want to learn more about 
the effects of marijuana to determine its effectiveness as a 
medicine. Dering-Anderson said she supports the medical use of 
marijuana for adults, is not yet sure if she supports it for children 
and doesn't have a stance on its recreational use.

Baldwin said he wants more research to determine if the benefits of 
medical marijuana use outweigh the detriments.

"It's crazy that we don't know more about this plant than we do," 
Dering-Anderson said, adding that it's under-researched because 
there's no money in doing so, because no company can legally market marijuana.

"Who owns the patent? God?" she said.

Marijuana smoking has also overtaken cigarette smoking, according to 
the study. Dering-Anderson said teenagers are getting the message 
that cigarettes cause lung cancer but don't think marijuana causes 
health problems. She referenced several studies, one titled 
"Cannabinoid effects on ventilation and breathlessness" by Elspeth 
Pickering, which showed that cannabinoid, found in marijuana, can 
actually be lung-protective.

Regardless, she doesn't recommend recreational use of the drug, 
especially for those whose brains are still developing.

"I'm not a proponent of young people abusing their bodies," she said. 
"I'm not a proponent of young people getting stoned."
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MAP posted-by: Jay Bergstrom