CANNABIS JOINT 'AS HARMFUL AS SMOKING FIVE CIGARETTES'

A single cannabis joint damages the lungs as much as smoking up to
five cigarettes at once, researchers say. The drug forces the lungs to
work harder by obstructing the air flow and causes chest tightness and
wheezing, a study found.

The news comes after research published last week showed that cannabis
could more than double the risk of developing psychotic illnesses such
as schizophrenia. Experts found that any use of cannabis - even taking
the drug just once - was associated with a 41 per cent greater risk.
People who smoke the most cannabis were found to be the most likely to
suffer a psychotic breakdown marked by delusions, hallucinations or
disordered thoughts.

Campaigners renewed their calls for the Government to reverse its
decision to downgrade cannabis to a class C drug.

The experts, including Professor Richard Beasley from the Medical
Research Institute of New Zealand, published their research today. It
will be carried later in the journal Thorax.

A total of 339 volunteers underwent high definition X-rays of their
lungs and took part in breathing tests to assess their lung function.
They were also asked about their smoking habits. The results showed
that cannabis smokers experienced wheezing, coughing, chest tightness
and phlegm.

The experts noted that the drug diminished the numbers of small
airways that transported oxygen and waste products to and from blood
vessels.

The extent of this damage was directly related to the number of joints
smoked, with higher consumption linked to greater incapacity, the
researchers said.

The effect on the lungs of each joint was equivalent to smoking
between two-and-a-half and five cigarettes in one go, they added.