'NATURAL' CANNABIS MANAGES MEMORY

Cannabis-like chemicals in the brain play a key role in erasing nasty
memories, a study has found.

Researchers in Germany have found that cannabinoids, produced naturally in
the brain, help to manage fear.

They believe that a lack of these chemicals may explain why some people have
difficulty forgetting painful events and suffer from post-traumatic stress
disorder or phobias.

The researchers suggest that new drugs to increase the production of
cannibanoids in the brain could help these patients to forget their painful
memories.

Doctors at the Max Planck Institute of Psychiatry in Munich made their
discovery in laboratory tests.

Mutated Mice

They bred two groups of mice. The first was engineered to produce more
cannabinoids while the second was engineered to produce fewer of these
chemicals.

They then subjected the mice to a series of tests. These involved a loud
tone followed by a light electric shock to the foot.

They found that mice which produced fewer cannabinoids froze when they heard
the tone, anticipating an electric shock.

The mice which produced more cannabinoids appeared to forget to associate
the tone with the electric shock and didn't freeze.

The authors suggested their findings showed that cannabinoids played a key
role in erasing painful memories.

They added that their results could one day be used to develop new
treatments for people who have difficulty forgetting painful events.

These include patients with post-traumatic stress disorder, phobias or
anxiety disorders.

Writing in the journal Nature, they said: "Overall our findings suggest that
the endogenous cannabinoid system could represent a therapeutic target for
the treatment of diseases associated with inappropriate retention of
aversive memories or inadequate responses to aversive situations such as
post-traumatic stress disorders, phobias, and certain forms of chronic
pain."

However, they warned that cannabis itself would not have the same effect
because it overflows the brain and is not specific enough to extinguish the
unpleasant memory.

Dr Pankaj Sah, a neuroscientist at the Australian National University in
Canberra, welcomed the study.

In an accompanying article in Nature, he said: "The finding might have
implications for treating anxiety disorders in humans."

He added that the study may explain why some people with mental illness turn
to cannabis.

"It may be a form of self medication for the sometimes extreme anxiety that
these people experience," he said.