HYSTERIA OVER CANNABIS IS GETTING IN THE WAY OF TRUTH

Gordon Brown has been a great supporter of science. It's a pity he's
allowed heart to rule over head in his desire to reclassify Britain's
most popular illegal drug

Any scientist concerned about the relevance of what they do in the
lab to the nitty-gritty of everyday life will have one memory that
rivals in vividness John Kennedy's assassination or the death of
Diana. It is the image of John Gummer, then Minister of Agriculture,
in May 1990, attempting to force-feed a hamburger to his daughter
Cordelia. He was, of course, making a statement about the safety of
British beef.

Labour came in with a promise to develop policy on the basis of
evidence rather than ministerial whim or political expediency. I was
in the audience at the Royal Society on 10 April 2002 when Tony Blair
gave his now-famous 'science matters' speech. The scientific
establishment was there in force. The portraits of Newton and Hooke
looked down at the throng - more like a children's Christmas party
than a gathering of the white-coated great and good. And we were
rewarded with a treat as jolly as any panto. Tony was Aladdin,
rubbing his lamp over GM food, nuclear power, embryonic stem cells,
nanotechnology and the use of animals in research. His vision was of
science at the heart of the future of this country, not just a driver
of the economy, but a source of rational decision-making.

But if Tony Blair was Aladdin, Gordon Brown was the Genie. Mr Brown,
the paymaster, transformed ideology into action. From the first
comprehensive spending review in 1999 to his last Budget in 2007,
Gordon Brown has consistently championed science. Now Brown as Prime
Minister faces what could be a pivotal test of his personal
commitment to evidence-based government - the question of whether the
classification of cannabis should be shifted back from C to B.

Let me be clear about where I stand on the issue of drugs of
potential abuse: I have been deeply embarrassed by accusations that I
favour the legalisation of all drugs. In fact, I believe that the
rise of illicit drug use is one of the most corrosive changes in our
society during my lifetime. Cannabis has led the rise of drug
culture. Nearly one-third of Britons between 16 and 59 admit that
they have smoked it. It should be a source of national shame that
Britain is a world leader in its drug problem. In 2003/4 (the last
year analysed), Britons spent UKP5.3bn on illicit drugs and the
annual socioeconomic cost of drug-related crime was estimated to be
more than UKP13bn.

The 1971 Misuse of Drugs Act established the ABC system for
classifying illegal drugs. The Advisory Council on the Misuse of
Drugs (ACMD) was set up to provide the Home Secretary with the best
possible expert evidence of potential harm. But what we now see is a
system distorted by history and hysteria. Drugs such as LSD and
Ecstasy were classified A at an early stage in their impact on the
street, as much to try to stop the expansion of their use as to
signal genuine evidence of their harm. They still sit in A, alongside
heroin and crack cocaine, despite the fact that they are indubitably
less dangerous to the user or to society. Cannabis has become the
football in a contest between evidence and passion.

In 2000, the recommendation from a committee of the Police
Federation, chaired by Ruth Runciman, that the whole system of
classification should be overhauled was rejected. But David Blunkett,
as Home Secretary in 2001, asked the ACMD for fresh advice about
cannabis, then a class B drug. The classification was changed in
2004. Ever since, the government has seemed uncomfortable. Successive
Home Secretaries - Charles Clarke in 2005 and Jacqui Smith last year
- - have gone through the ritual of asking the ACMD if they are really sure.

What, then, are the concerns? First, cannabis remains the most
commonly used illegal drug. But its use has been falling steadily
since 2000, with no hint that this decline was affected by
reclassification. Home Office statistics show that cannabis use by
16- to 24-year-olds has fallen by about 20 per cent since 2004. So,
if we naively argue from correlations (the basis of so much of the
evidence about harm), returning cannabis to B would be expected to
increase its use.

Second, there is concern about the message that reclassification has
sent. But there is no evidence that classification influences the
attitude of young people to drugs. Amphetamines, cocaine and ecstasy
are all runners-up to cannabis in the league table of popularity in
this country - and they are all class A. Usage of cocaine has grown
over the past eight years, as that of cannabis has declined. Third,
there is, quite rightly, a particular worry about young people. Yet
the the government's own figures show that only one 11-year-old in
150 has tried cannabis in the last year, while 4 per cent have
sniffed glue and fully 21 per cent have drunk alcohol.

Indeed, glue-sniffing and drinking (neither of which is regulated
under the Misuse of Drugs Act) are the dominant drug problems among
school children. About 5 per cent of 11- and 12-year-olds admit to
having been drunk at least once in the past month. And among all boys
under the age of 16 who said that they had drunk alcohol in the past
month, 11 per cent reported being involved in a fight and 2 per cent
had ended up in hospital!

Finally, there is the issue of a possible link between cannabis use,
especially the stronger varieties now on the street, and mental
health problems. Parents are now more worried that their children
will become schizophrenic than they were five years ago, that they
would get a criminal record.

We should take very seriously the growing evidence of a link between
cannabis smoking and psychosis. But this is still in the realm of
correlation rather than causation. Cigarette-smoking and drinking are
also very high among young people heading for schizophrenia, but no
one has suggested that they cause psychosis. And what of the alarming
stories of horrifyingly powerful 'skunk'? Some newspapers have told
us that the level of THC, the active ingredient, in street cannabis
today is 20 or 30 times higher than 10 years ago. That would be
rather surprising, given that THC content was 7 per cent on average in 1995.

In reality, two studies, due to be published later this year,
concluded that the average THC content has doubled. This might be a
cause for some concern, but what we don't know is whether this has
affected the amount of cannabis that users smoke. Whitehall
'sources', preparing us for the expected rejection of the ACMD
recommendation that cannabis should remain a class C drug, tell us
that the government is determined to 'send a message' about its
concerns. The strongest message that it could send is to agree to
undertake the comprehensive review of drug classification that
Charles Clarke hinted at three years ago.

When it comes to drugs, we, as a nation, need to agree on our goals.
We should aspire to a society in which people understand the real
dangers of drugs of all kinds (including alcohol and tobacco, which
account for 95 per cent of drug-related deaths). We need to focus on
protection and education of young people. And we need to support the
government in its commitment to policies based on reduction of harm
rather than slogans and macho gestures.

Science has benefited hugely from the period of Labour government,
not only in the steady rise in public funding but in the affirmation
of faith in evidence as the foundation of policy. The decision on
cannabis will be seen by many scientists as an indication of the
reality of this government's commitment to reason and expertise. I
hope that it won't be Gordon Brown's hamburger moment.