POT BLOCKS PAINFUL MEMORIES, STUDY SAYS

Can it finally be medical proof of the old hippie bromide smoke your
troubles away?

An international group of biochemists and pharmacologists has found that
the brain can use cannabis to wipe away painful memories.

The findings, published yesterday in the journal Nature, are the results of
experiments on mice. But the study's lead author, Beat Lutz of the Max
Planck Institute of Psychiatry in Munich, said that the findings may have
implications for humans.

"The obvious idea is to smoke marijuana and to get rid of bad memories," he
said yesterday from Munich. "It can erase bad memories faster. But it has
to be supported by psychotherapy."

The findings add to the mounting evidence that marijuana, an illegal drug,
may have widespread medical benefits.

Canada is caught up in a policy struggle over marijuana. The Department of
Health grows the stuff and has set up a system so that the sick can legally
possess it for medical reasons. The federal government has a stash of
several hundred kilograms but can't figure out how to distribute it to
those in medical need, because selling and buying the substance is illegal.

Federal Justice Minister Martin Cauchon has been talking about
decriminalizing the substance, and he admitted to smoking it.

Dr. Lutz's study will only add to the argument in favour of
decriminalization. But it is also a landmark in medical terms because it
deals with one of the central survival mechanisms of the vertebrate brain:
the ability to spot danger and flee from it.

Scientists have long understood that the brain can reprogram itself not to
flee if the danger goes away. That is called extinction of a memory. But
scientists have not understood how it happens.

Dr. Lutz's research shows that the answer lies in the body's store of
cannabinoids, or cannabis-like natural chemicals, produced whenever the
body needs them. The brain has a receptor for these cannabis-like chemicals
and can use them to help reprogram the response to a fear.

A problem is that the fear reaction can stick around when no longer needed.
That can lead to panic attacks or paralyzing irrational fear.

Dr. Lutz said his finding could mean that a person in the grip of trauma
might be able to summon up the terrible memory, with the help of a
psychotherapist, then smoke marijuana to enhance the ability of the brain
to extinguish the memory.

He said that smoking is by far the most efficient way of getting the
substance to the brain, although researchers are looking at an aerosol to
administer it straight to the lungs.

But Dr. Lutz was vehement in pointing out that simply smoking dope is not
the way to take away the emotional pain. If this were to work, the patient
would have to consciously retrieve the memory and concentrate on
extinguishing it through the moderate, controlled use of cannabis. The
practice of smoking dope to get happy is not going have this therapeutic
effect.

Harold Kalant, a professor emeritus of pharmacology at the Centre for
Addiction and Mental Health with the University of Toronto, also cautioned
against misinterpretation of the findings. He noted that heavy, regular use
of marijuana has well-documented negative effects.

And too much marijuana can diminish the brain's ability to lay down new
memories, rather than aid the removal of bad ones. "This could make matters
worse," he said.

Dr. Kalant also cautioned against believing that any drug is a magic
medical bullet. He pointed out that morphine, cocaine and heroin were
hailed with "wildly ecstatic claims" at first.

"Drugs are not a cure-all. Every drug has a downside," he said.