Saturday, November 8, 1997

Now doctors say nicotine may be good for our mental health

By BOB BEALE

Why do so many hard-core smokers ignore grim reality and stick with their deadly habit? A surprising and increasing amount of evidence suggests they are not simply addicted, they've found that nicotine is actually "good" for them.

No-one is advocating smoking, but some researchers speculate that people may one day use nicotine patches, gum or nasal sprays to help manage a range of mental disorders or to protect them from memory loss.

Smokers often claim that having a cigarette gives short-term gains in their mental performance, alertness, concentration, ability to carry out repetitive tasks, and improves speed and accuracy when processing information.

Experimental evidence is beginning to back them up, along with findings that many smokers seem to get a protective effect against disorders such as Parkinson's disease.

While it seems at first shocking that such a reviled, addictive and toxic substance may have a beneficial side, nicotine may indeed help in some medical treatments, according to Dr Cynthia Pomerleau, a researcher at the University of Michigan's Nicotine Research Laboratory.

The growing realisation that many hard-core smokers who do not respond to public health campaigns may be using nicotine to "self-medicate" other problems has led her to call for more research into the drug's potential therapeutic uses.

Australian researchers at the University of New England, for example, are planning a study to test whether people at risk of memory loss and Alzheimer's disease can benefit from wearing nicotine patches.

"There's no doubt that nicotine is a psychoactive drug - it's the actual smoking that is the killer, not the nicotine as such," the study leader, Dr Ian Price, said yesterday.

A recent paper in the medical journal The Lancet described how nicotine patches were used to help a woman gain more movement in her spastic arm.

A treatment has also been reported using the patches to help manage a case of Tourette's syndrome.

"There is mounting evidence that smoking is becoming increasingly concentrated in people at risk for major depressive orders, adult attention deficit hyperactivity disorder, anxiety disorders and bulimia or binge-eating," Dr Pomerleau said.

"People with these conditions often use nicotine to help manage their symptoms. We need more data on the possible toxic effects of nicotineto weigh against its possible therapeutic effects," she said.The picture is confused by nicotine's paradoxical nature. It is a potent rat poison and insecticide, for example, but in tiny amounts in the human brain it can also act as both a stimulant and a relaxant.

Nicotine is known to target receptors in the brain vital in stimulating the transmission of signals between cells, but a report last year in the science journal Nature revealed that nicotine also stimulates the release of dopamine, the transmitter involved in sensing pleasure. But something in cigarette smoke - probably not nicotine - also inhibits the production of an enzyme that breaks down dopamine, the report noted.

That may explain why so many alcoholics and cocaine addicts are also heavy smokers: tobacco not only enhances the pleasurable "hit" of the other drug but prolongs the sensation.

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