by JENNY HOPE, Daily Mail

Updated:02 May 2003

More than 30,000 cannabis smokers could die every year, doctors warn today.

Medical experts blame the Home Secretary for creating confusion about the risks posed by the drug - leading young people wrongly to believe it is harmless.

They claim David Blunkett's decision to reclassify cannabis as a class C drug - putting it on a level with anabolic steroids and prescription painkillers - sent out the wrong message and played down the devastating health effects of its regular use.

Professor John Henry, a leading authority on the drug, said the change - due to take place this summer - had undermined doctors' efforts to highlight the risks.

He said: "Cannabis is as dangerous as cigarette smoking - in fact, it may be even worse - and downgrading its legal status has simply confused people.

"We have a clear public message about cigarette smoking. Every year, the number of smokers gets smaller and the message on packets about the dangers gets bigger.

"At present, there is no battle against cannabis and no clear public health message."

In today's issue of the British Medical Journal, Prof Henry and other doctors from Imperial College, and St Mary's Hospital, both in London, say cannabis could be a major contributor to UK deaths.

Researchers calculate that if 120,000 deaths are caused among 13million smokers, the corresponding figure among 3.2million cannabis smokers would be 30,000.

The drug can cause cancer, lung disease and abnormalities associated with serious mental illness.

Users are up to six times more likely to develop schizophrenia.

The British Lung Foundation says smoking three joints a day can cause the same damage to the airways as a pack of 20 cigarettes.

Prof Henry added: "Even if the number of deaths turned out to be only a fraction of the 30,000 we believe possible, cannabis smoking would still be described as a major health hazard.

"If we add in the likely mental health burden to that of medical illnesses and premature death, the potential effects of cannabis cannot be ignored."

Dr William Oldfield, from St Mary's Hospital and one of the authors of the article, said: "Cannabis and nicotine cigarettes have a different mode of inhalation. The puff taken by cannabis smokers is two-thirds larger, they inhale a third more and hold down the smoke four times longer.

"All these factors could contribute to illnesses of the heart and respiratory system, particularly as the chemicals in cannabis smoke are retained in the body to a much higher degree."

He said the cannabis used today - especially that bought in the Netherlands - was up to 40 times stronger than that used by Flower Power hippies in the 1960s.

The level of active ingredient in cannabis, tetrahydrocannabinol (THC) has increased from around 0.5 per cent 20 years ago to almost five per cent today. THC affects the heart and blood vessels and many sudden deaths have been attributed to cannabis smoking.

In Britain, about eight million people admit to smoking cannabis, with at least one-third of youngsters claiming to have used it at some time. They include Prince Harry, who admitted smoking the drug while a pupil at Eton.