WHY THE GP MAY OFFER YOU CANNABIS

Sufferers of MS have long campaigned for the drug to be legal for
medicinal uses. Their goal may be in sight.

Once we only smoked it to get high; now it looks set to be a valued
addition to the medicine cabinet. The announcement last week that
marijuana might reduce stroke damage and protect against Alzheimer's
is just the latest in a string of beneficial effects, recently
uncovered by researchers. And there is undoubtedly more to come.
Marijuana contains a rich cocktail of chemicals whose functions are
only just being unravelled. Already research into its mechanisms has
led to the discovery of a neurotransmitter system in the brain that
was totally unexpected.

"What we have found so far suggests that cannabis could form the basis
for an entirely new approach to pain," says Professor Howard Field of
the University of California, San Francisco. In Britain Dr Geoffrey
Guy, recently granted the first Home Office licence to grow and
research cannabis, also believes that we have only just begun to tap
its possible uses. "The next condition that is going to benefit is
epileptic seizures," he predicts.

Until recently it was impossible to get funding to study cannabis
unless you wanted to show how dangerous it was. But about 18 months
ago, there was a sea change in the American research establishment's
attitude, after the residents of California and Arizona voted to
legalise marijuana for medical purposes.

The prestigious Institute of Medicine of the National Academy of
Sciences performed a U-turn and began an investigation into the claims
that marijuana was beneficial for a remarkable range of disorders,
including glaucoma, pain, muscle spasm in Multiple Sclerosis and loss
of appetite in AIDS patients. As a result cannabinoids - the chemicals
in the plant that affect particular cells in the brain - have become a
hot topic. In two weeks' time (July 23 to 25) an international
conference in France on cannabinoids will be discussing why marijuana
is emerging as such a panacea.

Meanwhile, in this country the BMA has thrown its considerable weight
behind a campaign for the medical use of marijuana. This has
encouraged the Home Office to grant Dr Guy his licence to grow
marijuana for the purpose of research at a secret location in southern
England and to run clinical trials. What he's discovered so far should
change your way of looking at the humble joint for ever.

"Marijuana contains about 400 active chemicals," says Dr Guy, founder
of GW Pharmaceuticals. "The conventional drug company approach to
medicinal plants is to extract a single active ingredient, which in
this case is generally assumed to be one known as THC, but this is
very short-sighted."

In evidence he recently presented to the House of Lords Committee on
cannabis Dr Guy explained that THC - "the one that gets you high" -
was just one of 60 cannabinoids that can affect receptors in the
brain. "In addition to them, the plant's essential oils have a range
of valuable properties - anti-fungal, anti-bacterial and
anti-inflammatory." Despite all this potent activity, cannabis has the
startlingly unusual property of being incredibly safe. The difference
between a therapeutic dose and a deadly one is 40,000. By comparison,
the figure for aspirin is 25, while morphine is 50.

For now, Dr Guy is looking at the cannabinoids, particularly CBD, the
one found to protect the brain after a stroke by mopping up dangerous
free radicals. He believes it will also be useful in treating
epileptic seizures. "It's only in the past year that we have been able

to separate it from its close relative CBC, so now we can begin to
study it properly."

But one of the most dramatic medicinal effects of cannabis is the way
it stops the pain of muscle spasms that come with MS, against which
conventional opiate-based painkillers are useless. Literally a few
puffs on a joint can bring relief. "This is startling in
pharmacological terms," says Dr Guy. "No other painkillers work that
fast or at such low doses." The latest American research into where
cannabinoids work in the brain is beginning to unravel what's going
on.

For over 20 years we've known that the brain has its own pain-control
system that uses natural chemicals called endorphins. Morphine is a
painkiller because it taps into that system. There are other systems,
such as the one based on serotonin, controlling mood. Now it turns out
there is a system that cannabinoids can manipulate.

"We now know there are two sorts of cannabinoid receptor - CB1 and
CB2", says Professor Steven Childers of Wake Forest University school
of medicine in Winston Salem, New Connecticut. "CB1 is found all over
the brain while CB2 is found in the body, especially in the immune
system. No one would ever have predicted that receptors for marijuana
would exist in such high quantities."

What's revealing is where these receptors are found in the brain.
"Motor systems are packed with them," Childers continues. "This may
partly explain why cannabis is said to help with the muscle spasms of
Multiple Sclerosis."

But it is pain control that is creating the most excitement. And all
this may have a decisive effect on the wider drug culture.
Increasingly, proper trials are showing that whole plant extracts are
as effective, with fewer side effects than the synthesised "active
ingredient". If Dr Guy's trials come up with the results, that could
lead to a big change in the sort of pills we are prescribed. And
that's really heavy, man.

Checked-by: "Rich O'Grady"