Evil weed or useful drug?

The federal government’s National Institute on Drug Abuse says that it is “not yet determined’’ whether marijuana increases the risk for lung and other cancers.

Respiratory problems: Smoking one marijuana joint has similar adverse effects on lung function as 2.5 to 5 cigarettes, according to a New Zealand study published in Thorax in July 2007. A small Australian study published in Respirology in January 2008 showed that pot smoking can lead to one type of lung disease 20 years earlier than tobacco smoking.

Addictive potential: The National Institute on Drug Abuse says “repeated use could lead to addiction,’’ adding that some heavy users experience withdrawal symptoms such as irritability and sleep loss if they stop suddenly.

Mental effects: Cannabis may increase the risk of psychotic disorders, according to a 2002 study in the American Journal of Epidemiology. And the national drug abuse agency warns that “heavy or daily use of marijuana affects the parts of the brain that control memory, attention, and learning.’’ A study of 15 heavy pot smokers published in June 2008 in the Archives of General Psychiatry showed loss of tissue in two areas of the brain, the hippocampus and amygdala, regions that are rich in receptors for marijuana and that are important for memory and emotion, respectively.

Vaporizing vs. smoking: The push now among proponents of medical marijuana is toward inhaling the vapor, not smoking. Vaporizing is a safe and effective way of getting THC, the active ingredient, into the bloodstream and does not result in inhalation of toxic carbon monoxide, as smoking does, according to a study by Abrams published in 2007 in Clinical Pharmacology and Therapeutics.

Bottom line: From a purely medical, not political, point of view, my take is that if I had medical problems that other medications did not help and that marijuana might, I’d try it - in vaporized form.

Just as Marcy Duda does. “You use it as you need it. You can be normal. You can function,’’ she says. “I don’t get high. I get by.’’