for National Geographic News
Scientists at the Mayo Clinic in Rochester, Minnesota, have found that certain drugs used to treat Parkinson's disease can cause patients to become addicted to gambling. The drugs, called dopamine agonists, also have been found to boost patients' appetites for sex, food, and alcohol.
"This is a striking effect," said J. Eric Ahlskog, a neurologist at the Mayo Clinic. "Pathological gambling induced by a drug is really quite unusual."
In one case, a 54-year-old married pastor gambled daily at the local casino, hiding his losses from his wife.
In another, a 41-year-old computer programmer who had never gambled in his life became "consumed" with Internet gambling.
In a third, a 68-year-old man with no history of gambling lost more than U.S. $200,000 at casinos over a six-month period.
All three of the men were taking medication for treatment of Parkinson's disease.
The study was posted online yesterday and will appear in the September issue of Archives of Neurology.
Out of Character
Parkinson's disease is a neurological disorder that causes trembling, stiffness of the limbs, and impaired balance and coordination. It is the result of a loss of brain cells that produce the chemical dopamine.
This chemical not only helps regulate movement and balance but also affects the brain's pleasure and reward centers. Dopamine is released in times of enjoyment and might serve to reinforce compulsive behavior such as gambling.
The Mayo findings are not entirely new. Several recent reports have linked dopamine-replacement therapy to pathological gambling. In a 2003 study, 1.5 percent of Parkinson's patients being treated with dopamine agonists developed compulsive gambling.
The scientists studied 11 patients who started gambling between 2002 and 2004 while under treatment for movement disorders. In routine clinical interviews with doctors, the patients admitted they had been gambling too much.
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