GENE MAY KEEP SMOKERS HOOKED ON NICOTINE

HOUSTON (Reuters) - Smokers who cannot quit may have a gene that makes them
enjoy the nicotine in tobacco too much, doctors said Tuesday.

The finding could explain why some people find it easier to stop smoking
than others, said Margaret Spitz, chief of epidemiology at M.D. Anderson
Cancer Center. ``Even after years of smoking, some individuals are able to
quit the habit while others are unsuccessful despite their cessation
efforts. This study sheds light on why that may occur,'' she said in a news
conference.

Simply put, ``They get enhanced pleasure when they smoke,'' Spitz said.
``They're going to enjoy it more and it's going to be harder for them to
stop.''

The gene exists in about 10 percent of the general population and about 30
percent of smokers, based on a three-year study conducted at M.D. Anderson.

Spitz said the gene controls the way nicotine stimulates the production of
dopamine, a chemical that passes messages between nerve cells, in the
brain. Studies have found that nicotine, alcohol and illicit drugs induce
pleasure by causing dopamine releases.

The same gene that contributes to nicotine addiction is like a siren's song
for other vices, said Spitz. It has been implicated in drug addiction,
alcoholism and obesity, she said.

The Houston researchers found the genetic link to smoking in a study of 156
lung cancer victims and 126 control subjects.

Spitz said more research must be done to confirm the findings, but that it
could eventually lead to new, more effective drugs for quitting smoking.
``The more we know about the biological basis for nicotine addiction, the
greater likelihood we can stop it,'' she said.