CANNABIS: A DRUG MORE DANGEROUS THAN HEROIN

The dangers of cannabis use by young people have been evident for
several years.

Growing numbers of teenagers are encountering mental health problems
and their distressed families, searching for answers, are discovering
an unwelcome truth: that everywhere circumstantial links exist
between heavy cannabis use and various forms of psychosis.

Most painfully of all, these families are realising that there is no
way back; that the damage is done.

This is the common pattern.

A bright child with no obvious psychological problems reaches his
mid-teens (it tends to be boys rather than girls) when suddenly his
school work starts to deteriorate. He seems to have trouble thinking
clearly; he starts to miss lessons and becomes isolated from friends.

He complains that people are talking about him behind this back. The
teenager may get to university, but then starts to suffer depression
and psychosis.

At some point, the parents learn their child has been a heavy
cannabis user for years.

He may drop out, and find it difficult to get a job. In severe cases,
he will become overwhelmed with paranoid fears. The workers at the
National Schizophrenia Fellowship (now called Rethink) hear this
heartbreaking story again and again from parents. No-one can say for
sure there are causal links between heavy cannabis use on developing
brains and psychiatric disorder.

The fact that X follows Y does not prove that X was the cause of Y.
But for many professionals in the field - such as Neil McKeganey,
professor of drug misuse research at Glasgow University, who says he
is now contacted frequently about people in their late teens running
into difficulty in this way - there is a conviction that smoking
cannabis may, indeed, be desperately harmful for predisposed youngsters.

We are deficient in knowledge about the most common street drug
(after alcohol). Concerned academics find it deeply disconcerting how
little research there is on cannabis.

They point to the fact that the government is preoccupied with heroin
and cocaine, and as a result has devoted little money to a drug that
has traditionally been regarded as a low-level problem.

You do not have to look far to see why. The fact that in 2004 the
government downgraded cannabis, moving it from a class B to class C
drug, means ministers are most unlikely to commission research that
would be likely to have a deeply embarrassing result, ie that the
reclassification was foolish.

Nobody willingly likes egg on their face; even fewer want to pay for it.

What evidence exists is hard to ignore.

In 1997, the British Journal of Psychiatry reported the adverse
effects of the drug, especially for adolescents. These included:
developmental problems, permanent cognitive impairment, psychosis,
chronic apathy (usually permanent) and an impact on the frontal lobe
function of the brain which can trigger schizophrenia and manic depression.

A Swedish study in the 1980s found heavy users of cannabis at the age
of 18 were six times more likely to develop schizophrenia in later
life. Two recent studies in Holland have found that the incidence of
psychosis in cannabis users was almost three times higher.

Depression was also three times more common in cannabis users.

In areas of south London, the incidence of schizophrenia has doubled
in 30 years.

Robin Murray, professor of psychiatry at the Institute of Psychiatry,
and a consultant at the Maudsley Hospital, is one of the few UK
experts studying cannabis.

For years, he has been warning about the harm the drug can cause,
pointing out that cannabis is the common reason for relapses in
psychiatric patients.

The same relapse was evident at Yale medical school when volunteers
were given THC, the major active ingredient of cannabis, by injection.

Professor Murray said recently: "Five years ago, 95% of psychiatrists
would have said cannabis does not cause psychosis.

Now I would say that 95% say it does. It is a quiet epidemic."

His was among research gathered for the Conservative Party's social
justice policy review this week. The report cited Professor Peter
Jones of Cambridge University, who found that eight out of 10 cases
of initial psychiatric disorders occurred in those who were heavy
users of cannabis. He said: "I work in a first-contact schizophrenia
service and it might as well be a cannabis dependency unit." He
estimates that children who start smoking cannabis at 10 or 11 treble
their risk of developing schizophrenia.

Mary Brett, the researcher who prepared the report for the Tories,
has criticised the Advisory Council on the Misuse of Drugs (who
reviewed the evidence in 2002 and advised the government to downgrade
cannabis) because not one single expert on cannabis, psychosis or
schizophrenia was a member.

The issue, it's clear, will be there to battle over at the next
General Election. It's a gloomy prospect.

I can think of nothing worse, or more unhelpful, than an unctuous
fight on old right/left lines over cannabis. We'll regress to a
polarity between the liberal baby-boomers who smoked grass 30 years
ago, with their nostalgic posturing, versus the traditional
hang-'em-and-flog-'em brigade.

It is crazy, for what was an argument about social freedoms is now a
medical argument about the risk of permanent brain damage.

But lost in the wilderness will be common sense, and damaged families
will be left to spin in the wind. You don't need to be a reactionary
to be deeply worried about cannabis . You just need to be a parent of
a teenager, or know a young person, as I do, whose life is now
blighted by mental ill health, most probably as a result of excessive
cannabis use. We need to remove this debate from the political arena
and put it into the hands of the scientists. Times have changed. We
are talking about a different drug, one which under the umbrella name
of skunk is massively more powerful than the grass of 30 years ago,
which was equivalent to two pints of beer. Nowadays the relatively
mild form of the drug is almost unobtainable. It has been overtaken
by artificially produced skunk, grown hydroponically in people's houses.

This form of the drug can be up to 20 times as powerful as the
natural product and one joint can have the effect of more than 10
pints. Small wonder that thousands of young people who smoke it
regularly lay themselves open to developing psychosis, or that
experts, given its widespread use, now view cannabis as more
dangerous than heroin. In their submission to the House of Commons
select committee on science and technology in July 2006, Rethink,
representing the parents, made the case that the government has not
contributed to the evidence base on cannabis, and has failed to
reflect the evidence that already exists. Damningly, the organisation
said that to its knowledge, the government has never attempted to
communicate the mental health risks of cannabis to the wider public
and to school-age children.

More than 25 years ago, in a report on cannabis, the World Health
Organisation said: "To provide rigid proof of causality in such
investigations is logically and theoretically impossible, and to
demand it is unreasonable." Surely we have more evidence now about
this quiet epidemic than was ever thought possible, and it is time to
warn teenagers of the dangers they face.