CANNABIS 'MAY CAUSE PUBLIC HEALTH DISASTER'

Doctors warn today that the use of cannabis, the most commonly-used
illegal drug in the UK, could result in a public health disaster on
the scale of that caused by tobacco because its toxic side-effects are
being ignored.

Evidence is growing that the drug that inspired a generation to make
love, not war, in the 1960s is a trigger of psychotic delusion, lung
disease and immune dysfunction.

A review by the British Lung Foundation says that the cannabis
available on the streets today is 15 times more powerful than the
joints being touted three decades ago. Smoking three joints a day
causes the same damage to the lungs as 20 cigarettes.

Dame Helena Shovelton, the chief executive of the British Lung
Foundation, said: "Fifty years ago smoking was thought to be a good
thing. Now it is described as a public health disaster. We don't want
to see the same happen with cannabis."

A survey earlier this year showed 79 per cent of children thought
cannabis was "safe" while only 2 per cent understood that it can be
damaging to health. The impression that cannabis promised a risk-free
high was increased when David Blunkett, the Home Secretary, declared
his intention to downgrade the drug from Class B to Class C, reducing
the penalties for possession, say campaigners.

The report from the British Lung Foundation says that sophisticated
cultivation has increased the potency of the plants used today with
the result that long-term studies of the drug's effects made in the
1960s and 1970s may no longer be relevant.

The evidence indicates that three cannabis joints cause the same
damage to the lining of the lungs as 20 cigarettes. Tar from cannabis
"joints" contains 50 per cent more carcinogens (cancer-causing
substances) than tobacco, and a joint is smoked more deeply than a
cigarette.

Studies show that habitual cannabis smokers are more likely to have
persistent coughs and suffer from bronchitis and wheezing episodes.
Cannabis is often mixed with tobacco and the ill-effects of the two
drugs together are greater than when smoked separately.

Dr Mark Britton, the chairman of the British Lung Foundation, said:
"These statistics will come as a surprise to many people, especially
those who choose to smoke cannabis rather than tobacco in the belief
it is safer for them."

It has been observed for more than a century that heavy doses of the
drug can induce hallucinations and it is now known that cannabis
causes the brain to increase production of the chemical dopamine. In
schizophrenia, the hallucinations result from an excess of dopamine,
so any drug that increases release of dopamine will worsen the
symptoms of schizophrenia.

Robin Murray, a professor of psychiatry at the Institute of
Psychiatry, London, says regular consumers of cannabis are at higher
risk of developing schizophrenia. Studies in Sweden and the
Netherlands showed regular consumers of the drug were up to six times
more likely to develop psychosis than those who didn't.

The British Lung Foundation report says a decreased immune function
may explain why there appears to be an association between cannabis
use and fungal and bacterial infections in people with cancer,
transplant patients and those infected with HIV.