Eleven patients with Parkinson’s disease developed pathological gambling behavior following dopamine agonist therapy, according to a report posted online July 11th by the Archives of Neurology.

Dopamine, which plays a role in the central nervous system in regulation of movement, balance and walking, also plays a central role in the behavioral reward system, reinforcing a myriad of behaviors. It has been implicated in the reward of gambling behavior.

M. Leann Dodd, MD, of the Mayo Clinic, Rochester, Minn., and her American colleagues reported on 11 patients seen and evaluated between 2002 and 2004 in the Mayo movement disorders clinic with Parkinson’s disease who had recently developed pathological gambling.

The researchers described the clinical features of the 11 patients. Pathological gambling developed in 7 of the 11 within one to three months of either reaching the maintenance dose, or increasing their dose of a dopamine agonist. While the other 4 patients did not report compulsive gambling until 12 to 30 months after initiating therapy, in all four the gambling resolved within months of discontinuing agonist treatment.

“The relationship of pathological gambling to dopamine agonist therapy in these cases is striking,” the researchers wrote.
Six of the patients developed additional behavioral problems simultaneously with the pathological gambling, which resolved as the gambling subsided. These included compulsive eating, increased alcohol consumption, increased spending, and hypersexuality.

“In summary, dopamine agonist drugs appear to be uniquely implicated as a cause of pathological gambling,” the authors concluded. “Both our series and prior reports have especially linked this to administration of the selective dopamine D3 agonist pramipexole. Disproportionate stimulation of dopamine D3 receptors might be responsible for pathological gambling in these Parkinson’s disease cases.”