CANNABIS STILL A DANGER

THE medical benefits of marijuana are only marginal - although worth
having for the seriously ill ("On the quiet, the US is legalising
marijuana", Andrew Sullivan, News Review, November 1). However, this
side of marijuana is being widely abused in California as a semi-legal
way of obtaining the drug. The hazards of smoking marijuana remain.

Cannabis smoke contains higher concentrations of carcinogenic
polycyclic aromatic hydrocarbons than tobacco smoke, and smokers
generally inhale more smoke for longer, depositing more than four
times as much tar in their lungs as cigarette smokers. A heavy smoker
of cannabis-and-tobacco joints (more than 10 a day), substantially
increases their risk of contracting lung disease including cancer, as
well as heart attacks and stroke.

I have spent most of my surgical life treating the ravages of tobacco
and, thanks to tobacco legislation, the scourge of these diseases in
the West is beginning to abate. In addition, the risk of inducing
psychosis in a proportion of users is high, and marijuana seems to
have a demotivating effect on the young.

Clive Quick

St Ives, Cambridgeshire