TUESDAY, Feb. 13 (HealthDay News) -- Scientists are learning more about gambling and other compulsive behaviors that are sometimes side effects of Parkinson's treatment.

Previous studies had found an association between Parkinson's drugs called dopamine agonists and impulse-control problems such as compulsive shopping, binge eating, hypersexuality, and pathological gambling.

The new study found that Parkinson's patients who are younger when they develop the condition have a personality trait known as novelty-seeking. Patients whose personal or family history included alcohol abuse are also more likely to suffer this side effect.

The study was led by Dr. Valerie Voon of the U.S. National Institute of Neurological Disorders and Stroke, and was published in the February issue of the journal Archives of Neurology.

Research that looked at the link between dopamine agonists and compulsive gambling determined that the risk of gambling was unrelated to medication dosage. This suggests that underlying character traits may interact with dopamine agonists and make people more likely to suffer this kind of side effect, according to background information in the new study.

The research team compared 21 Parkinson's patients who developed compulsive gambling after they started taking dopamine agonists to 42 Parkinson's patients who did not develop this kind of behavior.

All the patients, who visited a clinic in Toronto, Canada, were examined by neurologists and were assessed for levels of impulsivity, substance abuse, mood and anxiety disorders, and novelty-seeking traits, characterized by risk-taking behavior and excitement in response to new experiences.

"In keeping with our hypothesis, patients with Parkinson's disease who developed pathological gambling when receiving dopamine agonists had a younger age at Parkinson's disease onset, higher novelty-seeking scores, a personal or immediate family history of alcohol use disorders and impaired planning on an impulsivity scale," the study authors wrote. "A robust association was found with medication-induced mania (a psychiatric disorder involving excessive physical and mental activity and impulsive behavior)."

The researchers also found a weak association between compulsive gambling and younger age, Parkinson's disease that began in the brain's left hemisphere, and a higher score on a scale of impulsive behavior.

"Screening for such features and advising those at higher risk may be warranted," the study authors concluded.

More information

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