THE DANGEROUS IGNORANCE OF THOSE WHO SAY 'LEGALISE POT.'

There are literally millions of people of all ages and all classes in this
country who have tried cannabis and claim to have had no ill effects.

Indeed, as the Government launches its drugs White Paper - a document that
maintains the strict official ban on cannabis - it's probably fair to say
that the weight of liberal opinion is in favour of its legalisation.

There are MPs who argue that its use is harmless. At countless dinner
parties the law is derided. One serious broadsheet newspaper has
campaigned openly for cannabis to be made legal.

Why not, so the argument goes, when the drug is not nearly as dangerous as
heroin, nor as addictive as cocaine, nor as unpredictable in its
consequences as LSD or Ecstasy?

Why not, when the anti-cannabis laws are flouted so openly, when half the
students at universities have tried it and when the drug is said to pose
fewer dangers than either alcohol or tobacco?

Well, there are good reasons why not. As someone who, since the Seventies,
has studies the effects on the human brain of various drugs - including
cannabis - it seems to me that the 'legalise pot' campaigners are jumping
ahead of the evidence in a cause that owes more to fashion than to hard
science.

During my research I have come into contact with many different types of
cannabis user, from students who consume it on a casual basis to habitual
users.

I must stress I am not speaking as an anti-cannabis campaigners, I'm an
academic, not a pundit or a politician keen on promoting a particular policy.

But as the pressure grows to legalise cannabis, it seems to me increasingly
important that the facts should be understood, particularly by those who
argue that cannabis isn't really harmful, anyway. It is time we took a
long, dispassionate view of the evidence.

Take the claim that cannabis isn't addictive. Research demonstrates that
this simply isn't true. My own experience with students users shows that
they can and do suffer severe withdrawal symptoms when they try to come off
the drug.

Once I was unable to complete my study of one group of chronic cannabis
smokers in a commune because they could not keep their appointments.

They lost their academic edge, and their studies suffered badly. And,
crucially, those who stopped smoking the drug exhibited nor great improvement.

A study in the U.S. conducted about ten years ago, underlined the point. A
group of regular cannabis users were given oral doses of the drug under
strict laboratory conditions. Later, unknown to them, the drugs were
replaced by a harmless placebo.

Without heir regular genuine 'fixes', they ended up suffering tremors,
stomach pains, nausea, headaches and a range of other unpleasant
side-effects. One of the reasons is the way cannabis is absorbed by the
body. It isn't like alcohol, which can be sweated out within 24 hours.
The narcotic effects of a single joint last 48 hours.

But the various chemical residues in the drug find their way into the body
fat, where they remain for as long as a month. And of course regular users
keep on absorbing more and more. Contrary to claims by the legalise pot
campaign, it definitely effects the brain function. A Department of
Transport study in the late Eighties confirmed that cannabis impairs the
ability to drive. Another study showed that, after alcohol, cannabis is
the most common drug involved in road deaths.

Research into airline pilots who have smoked one moderate dose of the drug
not only found that it had a marked impact on performance, but that the
impairment lasted up to 48 hours.

Just a disturbing was the finding that, after 24 hours, those pilots were
unaware that their abilities were still affected, But they continued to
make potentially disastrous mistakes when they were tested on a light
simulator.

Now all this may seem somewhat overstated to the people who smoked the odd
joint back in the Sixties and seventies without seeming to suffer any great
harm. Indeed, the legalisation campaigners point to the experience of
those years as evidence that the drug is relatively safe.

But I fear they are missing the crucial point. Over the years, the
strength of the average cannabis joint has increased because of careful
plant-breeding and hydroponic farming to produce more potent varieties,
such as Silver Pearl and Skunkweed. The old reefer of the Sixties offered
a relatively mild dose. A modern joint can be as much as 30 times
stronger. And of course the very fact of that increase in strength adds to
the chemical deposits in the body and stimulates the desire for another
strong buzz.

Whether or not this ;leads on the experimentation with harder drugs may be
open to debate. But I think there is an analogy with alcohol abuse. Most
people like a drink, but relatively few go on to become alcoholics. It
must be true, however, that the more drinkers here are, the more alcoholics
there will be. I suspect the same pattern applies to cannabis. The more
users there are, the more will be tempted to try something stronger.

This, after all, is what is suggested by the experience in Holland, where
cannabis has been legal for years. The use of hard drugs has risen
noticeably.

It is interesting to note that the Dutch authorities have now reduces the
amount of cannabis that can be sold for personal consumption.

There is one other point that the legalisers tend to overlook: the risk of
cancer.

It took decades before the carcinogenic effects of tobacco smoke were fully
understood. How long will it be before it dawns on cannabis users that
they risk very nasty cancers of the throat, tongue and mouth, not to
mention emphysema and other chest troubles?

In fact, in some respects a joint can be more dangerous than a cigarette
because it has no filter and a higher igniting temperature.

If any future government is tempted to lift the ban on cannabis, it will
have to do so despite the evidence that it creates dependency, that it
impairs the cognitive function of the brain and that it poses a risk of
cancer.

The only argument hat is left concerns the undoubted fact that the present
law is so widely flouted as to be virtually unenforceable. But wouldn't
the law be equally unenforceable if the ban were lifted? After all, since
cannabis clearly has a deleterious long-term effect, many groups in society
would be forbidden from using it, no matter how liberal the Government
wanted to appear.

Could we ever contemplate pilots, bus drivers or surgeons using the drug?
How could we ever police a law that allowed some people to use the drug but
forbad others?

There has been plenty of emotion in the drugs debate, plenty of passion and
commitment. Am I alone in wishing for a more considered approach? And for
a climate if in which science and rational analysis can take the place of
tub-thumping zealotry?

Checked-by: Richard Lake