Pubdate: Sat, 16 Nov 2002
Source: Globe and Mail (Canada)
Section: Page F7
Copyright: 2002, The Globe and Mail Company
Contact:  http://www.globeandmail.ca/
Details: http://www.mapinc.org/media/168
Author: Alan Freeman

THERE'S A REASON THEY CALL IT GETTING WASTED

Researchers Warn Marijuana Is Worse Than Tobacco For Your Lungs And Is 
Linked To Schizophrenia.

LONDON -- Marijuana has always been seen as the laid-back drug. It might 
make you crave ice cream and chocolate cake or induce you to fall asleep, 
but it certainly wasn't dangerous.

Yet, as governments in Britain and Canada consider decriminalizing the 
drug, medical researchers are warning that smoking cannabis increases the 
risk of lung disease and, more disturbingly, that its use can exacerbate 
psychosis and that it is linked with the onset of schizophrenia in adolescents.

"We have the evidence of cannabis and its dangers," said Dr. Richard 
Russell, a respiratory specialist and a spokesman for the British Lung 
Foundation, which published a report this week on the dangers of cannabis.

"What we really want to avoid is the situation we had in the 1930s, '40s 
and '50s with cigarettes, where doctors were recommending tobacco as being 
good for you."

In its report, the lung foundation warns that cannabis is more harmful to 
the lungs than tobacco. It says smoking three joints a day can cause the 
same damage as 20 cigarettes, and tar from marijuana contains 50 per cent 
more carcinogens than that from tobacco.

Persistent users are risking lung cancer, emphysema, bronchitis and other 
respiratory illnesses, it says.

One of the major problems is posed by the way users smoke marijuana and 
hashish: They take puffs that are almost twice as large as those tobacco 
smokers take and hold the smoke in four times as long. "This means that 
there is a greater respiratory burden of carbon monoxide and smoke 
particulates such as tar than when smoking a similar quantity of tobacco."

The foundation also noted that in the 1960s, the average marijuana joint 
contained about 10 milligrams of tetrahydrocannabinol (THC), which accounts 
for the drug's psychoactive properties. Because of sophisticated 
cultivation techniques, the average joint today has 150 mg of THC, a 
15-fold increase.

Dr. Russell, the respiratory specialist, worries that young people think 
cannabis is a "cool drug" that is risk-free. A survey carried out this year 
showed that 79 per cent of British children believe cannabis is safe.

The Canadian government indicated in its Speech from the Throne last month 
that it is considering the decriminalization of marijuana possession.

Already, it gives exemptions to drug laws to allow sick people to have 
marijuana. On the other hand, pot grown for medicinal purposes in an 
abandoned Manitoba mine with Ottawa's sanction sits in storage.

In Britain, under a proposal due to become law next year, simple possession 
of a small amount of cannabis will no longer result in an automatic arrest 
although police will still be able to go after users in "aggravated" 
circumstances, such as smoking in the presence of children. Cannabis 
trafficking will also continue to bring a prison sentence.

Meanwhile, clinical studies on the use of marijuana for medicinal purposes 
are under way with HIV patients in Canada and with people suffering from 
multiple sclerosis in Britain.

The British Lung Foundation says it is not trying to get involved in the 
debate over whether cannabis should be legalized, leaving that to 
politicians. "Our report is not about the moral rights and wrongs of 
cannabis, but simply making sure everyone is completely clear about the 
respiratory health risks involved," said Dr. Mark Britton, chairman of the 
foundation.

Dr. Russell says he recently saw a 40-year-old patient in his clinic with 
"severe end-stage emphysema" and has about 18 months to live. The patient 
has been smoking three joints a day for the past 25 years, the equivalent 
of smoking 60 cigarettes a day from the age of 15, he says.

Studies of heavy cannabis smoking among Rastafarians in the Caribbean have 
also pointed to increased danger of early lung cancer, Dr. Russell says.

Les Iversen, a professor of pharmacology at King's College in London and an 
expert on cannabis, agrees that smoking marijuana poses dangers, but he 
says the report's findings are exaggerated.

There is no specific evidence linking cannabis smoking with lung cancer, 
Prof. Iversen says.

He says it's absurd to say smoking three joints is equivalent to smoking 20 
cigarettes because joints come in different sizes and strengths as do 
commercial cigarettes.

Although he adds, "I don't think any drug is safe."

Psychiatrists have also linked cannabis use to schizophrenia.

"People with schizophrenia do not take more alcohol, heroin or ecstasy than 
the rest of us, but they are twice as likely to smoke cannabis regularly," 
says Dr. Robin Murray, a professor of psychiatry at the Institute of 
Psychiatry in London.

Dr. Murray says cannabis, along with cocaine and amphetamines, encourage 
the release of dopamine in the brain, which in turn leads to increased 
hallucinations.

He notes that the incidence of schizophrenia in south London has doubled in 
the past 40 years, and he says increased use of both cannabis and cocaine 
could be at fault.

Dr. Murray cites a study that interviewed 50,000 conscripts to the Swedish 
Army about their drug use and followed up later. Heavy users of cannabis at 
the age of 18 were six times as likely to be diagnosed with schizophrenia 
by the time they were 33 than those who kept away from the drug.

Another study, this one in the Netherlands, interviewed 7,500 people about 
their consumption of drugs and looked at their behaviour over the next 
three years. Regular users of cannabis were more likely to develop 
psychosis than those who did not use the drug.

"Any public debate on cannabis needs to take account of the risks as well 
as the pleasure," Dr. Murray says. "Pro-marijuana campaigners claim, 
extrapolating from their Saturday-night joint, that cannabis is totally 
safe. Yet they would be unlikely to claim that a bottle of vodka a day is 
healthy on the basis of sharing a bottle of Chablis over dinner.

"No drugs that alter brain chemistry are totally safe," he says. "Just as 
some who drink heavily become alcoholic, so a minority of those who smoke 
cannabis daily go psychotic."

A major study on the links between cannabis and schizophrenia is due to be 
published in the British Medical Journal next week by Louise Arsenault, a 
biomedical researcher at the Institute of Psychiatry who was trained at the 
University of Montreal.

Research made public last year by Dr. Arsenault showed that young men who 
regularly smoke cannabis are five times more likely to be violent than 
those who avoid the drug. Using data from a study of 961 young adults in 
Dunedin, New Zealand, she discovered that one-third of those with a 
cannabis habit had a court conviction for violence by the time they hit 21 
or had displayed violent behaviour. That was three times the level of those 
who drank excessive amounts of alcohol.

The warnings about marijuana have not deterred members of Britain's 
Legalize Cannabis Alliance, who say the report is merely a selective study 
of existing medical literature, which ignores studies that discount the 
health threats posed by the drug.

"I've used it for 30 years and it doesn't seem to have affected my health," 
says Alun Buffry, the alliance's national co-ordinator.

"I stopped tobacco three or four years ago and I have noticed that since 
then my health has improved. My general level of energy has improved and I 
get more of a high from cannabis than the sleepiness I used to get, which I 
think had to do with tobacco."

Mr. Buffry argues that it would be best to legalize cannabis to control the 
quality of what is sold and eliminate "dirty supplies" that may include 
potentially harmful glues, fillers and colouring agents.

"I would argue that it would be far more dangerous illegal than it would be 
legalized," he says. "Even if cannabis were the most dangerous substance in 
the world, it is still consumed by millions of people."

Alan Freeman is The Globe and Mail's European correspondent.
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