Pot doesn't cause lung cancer, researcher says

Pot doesn't cause lung cancer, researcher says Also doesn't seem to cause emphysema or birth defects, Senate hearing told.

OTTAWA (CP) - Smoking marijuana does not seem to cause lung cancer, emphysema or cause birth anomalies in fetuses, a prominent U.S. researcher told a Senatecommittee Monday.

John P. Morgan of City University of New York Medical School said heavy marijuana smokers do show some symptoms of lung damage, such as coughing, frequent colds and bronchitis, but not the life-threatening conditions seen among tobacco smokers.

''We are some 30 to 40 years into this marijuana epidemic and still have not seen evidence of pulmonary cancer in marijuana smokers.'' He was speaking before a special Senate committee reassessing federal legislation and polices on marijuana.

Morgan said there are reasons to believe the heavy smoker of cannabis will not succumb to emphysema, a condition frequent among cigarette smokers.

He said cannabis contains just as many harmful compounds and irritants as tobacco, but even heavy marijuana smokers - those who consume four to six joints daily - don't smoke nearly as much as tobacco smokers. ''The critical issue is the amount of smoke inhaled.''

He said marijuana smokers have slightly more respiratory complaints than non-smokers, but the difference is so small that it is of no practical significance.

Morgan also criticized research purporting to show fetal damage among women who smoke marijuana and scoffed at the theory that marijuana is a gateway leading to hard drugs. ''Many critics in the United States have decided that marijuana incites some biochemical trance that leads people to tramp the streets looking for heroin and cocaine.''

But statistics show that most marijuana smokers never go on to other drugs, he said. ''There is no gateway, there is no credible gateway theory.'' He said prohibition of marijuana only makes young people more interested in trying it.

Rates of marijuana use in The Netherlands, where the drug is freely available, he said, are lower than in the United States where it is banned. He attributed opposition to decriminalization of marijuana to what he called ''the drug-law industrial complex'' in the United States. ''I don't believe anyone should go to jail for using a psychoactive substance,'' Morgan told the committee.

The committee's hearings continue.