Pubdate: Thu, 17 Apr 2014
Source: Sydney Morning Herald (Australia)
Copyright: 2014 The Sydney Morning Herald
Contact:  http://www.smh.com.au/
Author: Rebecca Smith, London Telegraph, London
Page: 14

SAFE-DRUG NOTION GOES TO POT: CANNABIS 'DAMAGES BRAIN'

Experimenting with cannabis on a casual basis damages the brain
permanently, research has found.

It is far from being a "safe" drug and no one under the age of 30
should ever use it, experts said.

People who had only used it once or twice a week for a matter of
months were found to have changes in the brain that govern emotion,
motivation and addiction.

Researchers from Harvard Medical School carried out detailed 3D scans
on the brains of students who used cannabis casually and were not
addicted and compared them with those who had never used it.

Two major sections of the brain were found to be affected. The
scientists found that the more cannabis the 40 subjects had used, the
greater the abnormalities.

Research author Hans Breiter, professor of psychiatry and behavioural
sciences at Northwestern University Feinberg School of Medicine, said:
"This study raises a strong challenge to the idea that casual
marijuana use isn't associated with bad consequences. Some people only
used marijuana to get high once or twice a week.

"People think a little recreational use shouldn't cause a problem, if
someone is doing OK with work or school. Our data directly says this
is not the case.

"I've developed a severe worry about whether we should be allowing
anybody under age 30 to use pot unless they have a terminal illness
and need it for pain."

The team examined sections of the brain involved in emotion,
motivation and addiction in 20 students who had used cannabis and 20
who had not. Anne Blood, assistant professor of psychiatry at Harvard
Medical School, said: "These are core, fundamental structures of the
brain. They form the basis for how you assess positive and negative
features about things in the environment and make decisions about them."

Jodi Gilman, a researcher in the Massachusetts General Centre for
Addiction Medicine, said: "It may be that we're seeing a type of drug
learning in the brain. We think when people are in the process of
becoming addicted, their brains form these new connections.

"Drugs of abuse can cause more dopamine release than natural rewards
like food, sex and social interaction. That is why . . . everything
else loses its importance."

The study is published in the Journal of Neuroscience.
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