Pubdate: Sun, 29 Jun 2003
Source: Sydney Morning Herald (Australia)
Copyright: 2003 The Sydney Morning Herald
Contact:  http://www.smh.com.au/
Details: http://www.mapinc.org/media/441

STUDIES WEED OUT THE GOOD NEWS AND BAD

Smoking marijuana will not cause long-term harm to your brain but it could 
have an impact on your time perception, two US research papers released 
yesterday reported.

University of California researchers said that though marijuana causes 
short-term harm to memory and learning - part of the brain's selective 
memory functions - it does not cause permanent brain damage.

"If there is an effect, it is very small," said Igor Gray, a professor of 
psychiatry who led the study of well-educated young people to assess the 
long-term impact of the drug on adults' neurocognitive abilities.

California approved a law in 1996 that allows doctors to prescribe cannabis 
for some patients. A number of US studies are examining the effects of 
cannabis and its use as a medicinal drug.

Meanwhile, University of Georgia scientists have shown, for the first time, 
that marijuana really does alter time perception, and most likely makes 
people more dangerous at the wheel of a vehicle and slower to respond in 
conversations - assuming that the behaviour of stoned rats offers clues 
about humans.

The scientists trained rats to tell the difference between short and long 
bursts of sound. If the sound was short, rats that pressed the right lever 
got a pellet of food. The animals had to press the other lever if the sound 
was long.

Once the rodents were stoned, however, they could no longer concentrate 
enough to press the feeder levers.
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MAP posted-by: Larry Stevens