CANNABIS SMOKING 'MORE HARMFUL' THAN TOBACCO

Smoking pure marijuana is at least as harmful to lungs as smoking tobacco,
a report from the British Lung Foundation concludes.

And in some key ways, it may be more dangerous.

For example, the BLF's review of previous research highlights that just
three marijuana joints a day causes the same damage to the lung's airways
as 20 cigarettes, mainly because of the way joints are smoked.

Individually, cannabis and tobacco produce the same constituents and
quantities of chemicals known to be toxic to respiratory tissue, other than
nicotine, the report says. But when cannabis and tobacco are smoked
together, the health effects are worse.

"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," says Mark Britton, chairman of the BLF. A UK survey conducted
earlier in 2002 found that 79 per cent of children believed cannabis to be
'safe'.

Deep Breath

A key finding highlighted by the review of 90 published papers is that the
amount of smoke taken into the lungs is two thirds larger if cannabis is
being smoked.

The smoke is also taken one third deeper into the lungs - and that smoke is
held an average of four times longer before being exhaled.

"You inhale deeper and hold your breath with the smoke for longer before
exhaling.

This results in more poisonous carbon dioxide and tar entering into the
lungs," says Helena Shovelton, BLF's chief executive.

Other points in the report include:

* Tar from cannabis cigarettes contains up to 50 per cent higher
concentrations of carcinogens benzathracenes and benzpyrenes than tobacco smoke

* THC, the primary psychoactive ingredient of cannabis, decreases the
function of immune system cells that help protect the lungs from infection

* The average cannabis cigarette smoked in the 1960s contained about 10
milligrams of tetrahydrocanabinol (THC), the primary psychoactive
ingredient. Today, it may contain 150 mg.

"This means that the modern cannabis smoker may be exposed to greater doses
of THC than in the 1960s or 1970s," says the report. "This in turn means
that studies investigating the long-term effects of smoking cannabis have
to be interpreted cautiously."

Mouth Spray

Cannabis is the most widely consumed illegal drug in the UK. In 2000,
almost 45 per cent of 16 to 29 year olds in the UK said they had used
cannabis at some point.

"We are not making any policy recommendations. The aim of this report is to
try to inform the public that if you do choose to smoke cannabis, be aware
of the health risks," says a BLF spokeswoman.

Cannabis-based medicines could be prescribed for medical use in the UK as
early as 2003, following the recent success of final-stage trials.

But medicinal cannabis is supplied through a mouth spray or in tablet form.

"We have always been keen to find additional ways of administering cannabis
as a medicine," says Nina Booth-Clibborn of the UK's Medicinal Cannabis
Research Foundation. "It did seem that smoking would not be the best way."

Lyndon Pugh, editor of pro-cannabis magazine CC Newz, is not impressed by
the report: "These allegations have been made before countless times. Lot
of things are dangerous, like driving."