Thursday, February 15, 2007

US scientists have found an association between the characteristics of
increased risk for compulsive gambling and Parkinson's disease medication.
Dr. Valerie Voon from National Institute of Neurological Disorders and
Stroke in Bethesda and colleagues found that 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. Behaviours associated with
impulse control-including compulsive shopping, hypersexuality, binge eating
and pathological gambling-have been associated with dopamine agonists,
medications used to treat Parkinson's disease. In studies examining the
relationship between dopamine agonists and compulsive gambling, the
likelihood of gambling problems was unrelated to the medication dosage,
which suggests that an underlying trait may interact with the drugs and make
an individual more vulnerable to this adverse effect. The researchers
compared the characteristics of 21 patients with Parkinson's disease who
developed pathological gambling habits after beginning to take dopamine
agonists with 42 patients with Parkinson's disease who did not develop the
compulsive behaviours. The participants were examined by neurologists for
the measured their levels of impulsivity, substance abuse, mood and anxiety
disorders, and the extent to which they displayed novelty-seeking traits,
characterised by impulsive and risk-taking behaviour 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 authors
write.

"A robust association was found with medication-induced mania 'a psychiatric
disorder involving excessive physical and mental activity and impulsive
behaviour'." Pathological gambling was also weakly linked to younger age,
Parkinson's disease that began in the brain's left hemisphere and a high
score on a scale measuring the impulsiveness of behaviours. Screening for
such features and advising those at higher risk may be warranted," they
conclude.