April 7, 2006
Family members of people taking some types of medication for Parkinsons disease have long suspected the treatment was triggering uncharacteristic, compulsive behavior.
Now a new study suggests its true patients who receive levodopa or dopamine agonists, the mainstays of Parkinson treatment are prone to pathologic gambling, hypersexuality, and compulsive shopping.
To examine the true extent of the problem, Valerie Voon, MD, of the National Institute for Neurologic Diseases and Stroke in Bethesda, Md., and her colleagues, conducted a prospective survey in almost 300 Parkinson patients, asking about pathologic gambling, hypersexuality, and compulsive shopping.
They followed up with in-depth psychiatric interviews for those reporting any of the three compulsive behaviors.
Among their sample, pathologic gambling started in 10 patients (3.4 percent) after they began treatment, which is double the number expected based on population-wide surveys. These patients had lost an average of $150,000. Hypersexuality was seen in seven patients, and compulsive shopping in two.
The researchers examined the medications patients were taking to see if these influenced risk for compulsive behavior. They found that almost all patients who developed these behaviors were receiving both levodopa and a dopamine agonist. Patients on levodopa alone were much less likely to develop a compulsive behavior. No single dopamine agonist was more likely than another to be associated with these behaviors.
One or another form of compulsive behavior was seen in 6 percent of the entire patient population, and 16 percent of those receiving both types of medication.
Voon cautions that these results must be interpreted with care, since the patients were drawn from a large specialty care center, and may not be representative of the Parkinson population as a whole.
"Larger multi-center trials are required to definitively determine the differences between Parkinson patients and the general population," Voon said. "Nonetheless, patients and caregivers should be aware of these commonly hidden behaviors."
