I’m Shep O'Neal with the VOA Special English Health Report.

Parkinson's Disease affects the nervous system and brain.

Parkinson disease is a brain disorder.  It usually develops after the age of sixty-five.  Among the signs are shaking, slowed movement and muscle stiffness.  Others include depression and reduced mental ability. 

With Parkinson's disease, nerve cells die in an area called the substantia nigra.  This area is in the middle of the brain.  The name is Latin for "black substance." 

The nerve cells that die are neurons.  They produce the chemical dopamine.  Dopamine carries signals to the part of the brain that controls movement and balance.  Dopamine is also linked to pleasure and reward centers in the brain. 

There is no cure for Parkinson's disease.  Mostly it is treated with drugs to increase the amount of dopamine in the brain.  The drugs are called dopamine agonists.  They are designed to control the movement problems.

Yet scientists have found that a new group of Parkinson’s drugs can have strange effects.  Some people develop uncontrollable urges to gamble.  These include people with little or no history of interest in games of chance.  Others have had an increased desire for sex, food and alcohol. 

Researchers at the Mayo Clinic in Rochester, Minnesota, did a study of eleven people on dopamine agonists.  All eleven patients said they developed gambling urges within three years of when they started treatment.  They began to gamble between two thousand two and two thousand four.  One person reportedly lost as much as two hundred thousand dollars.

Nine of the patients took a drug called pramipexole, also known as Mirapex.  The other two took ropinirole, sold under the trade name Requip.

Researchers say the gambling urge appeared to stop when the medicine was discontinued. 

Doctor Maryellen Dodd led the study.  She says fourteen other Mayo Clinic patients have since been found with the same problem. 

Still, experts say the drugs are effective treatments.  They say the unusual effects are uncommon.

The study is to appear in the Archives of Neurology in September. 

Several new medicines are being studied that may slow the progression of Parkinson's.  The National Parkinson Foundation estimates that one and one-half million Americans have the disease. 

This VOA Special English Health Report was written by Cynthia Kirk.  Our reports are online at voaspecialenglish.com.  I'm Shep O'Neal.