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MONDAY, Aug. 11, 2003 (HealthDayNews) -- A combination of some Parkinson's disease medications may produce a rare but potentially devastating side effect: addictive gambling behavior.
In the Aug. 12 issue of the journal Neurology, researchers report finding nine pathological gamblers in a group of more than 1,000 people being treated for Parkinson's disease. These people said they hadn't had any gambling problems in the past.
Dr. Mark Stacy, lead author of the study, says he began this study because he had two patients come to him reporting huge gambling losses soon after Stacy had changed the doses of their medications. Stacy is the medical director of the Parkinson's Disease and Movement Center at Duke University Medical Center in Durham, N.C., but was at the Muhammad Ali Parkinson Research Center in Phoenix at the time of the study.
He and his colleague then went back and reviewed their patient charts for a year. Out of 1,184 people with Parkinson's disease, they found seven other cases of problem gambling.
In all of the cases, the gambling was severe enough to cause financial problems. Two of the people reporting pathological gambling behavior had lost more than $60,000. On average, the people with gambling problems had been diagnosed with Parkinson's disease for 11 years before the start of their addictive gambling behavior.
All nine were taking levodopa and a dopamine agonist when their gambling problems began. Levodopa is a drug that changes into dopamine in the brain, and dopamine agonists activate dopamine receptors in the brain.
Dopamine is a neurotransmitter with many functions in the brain. People with Parkinson's disease have low levels of dopamine, which is believed to help control smooth movement. Dopamine also appears to affect mood and personality.
Of those with a gambling problem, eight were taking a dopamine agonist called pramipexole and the other was taking one called pergolide. None of the people studied who were taking levodopa alone reported problem gambling, and those taking a different dopamine agonist, ropinirole, also reported no problems.
Stacy says he's not sure how the medications cause addictive gambling behavior, but seven of the patients reported their problems began within a month of when their dosage was increased.
This suggests, Stacy says, that higher doses of the dopamine agonists act as a "catalyst" for problem gambling behavior.
Pathological gambling affects between 0.3 percent to 1.3 percent of the general population, according to the study, compared to 1.5 percent in the people taking pramipexole. Stacy says the availability of gambling around Phoenix and the need for seniors to find a place to socialize may have played a role as well.
When their medications were switched, or the doses were lowered, most of the patients were able to control or stop their gambling behavior, according to the study. Some of them also attended Gamblers Anonymous meetings.
Dr. Jay Van Gerpen, a neurologist and movement disorder specialist from Ochsner Clinic Foundation in New Orleans, says he wasn't surprised by this study's findings.
"Medicines for Parkinson's disease may elicit unwanted side effects relating to mood and personality," says Van Gerpen. "These medicines are extremely useful, but they may produce unwanted effects. Dopamine agonists can be associated with changes in personality, such as sexual inappropriateness, and changes in sleep cycles. Patients need to be aware of these possibilities."
Stacy says while the side effect is rare, it's important for doctors and patients to know that higher doses of these medications may increase the risk of problem gambling.
More information
For more information on Parkinson's disease, go to the National Institute of Neurological Disorders and Stroke. If you think you or someone you love may have a gambling problems, take this quiz from the National Council on Problem Gambling.
