Researchers at Muhammad Ali Parkinson Research Center in Phoenix, Ariz., examined the data of 1,884 Parkinson's patients who were seen during a one-year period. Nine patients - seven men and two women - were identified with pathological gambling.
"The risk of gambling problems in a Parkinson's patient is very small," said study author Mark Stacy, MD, who is now the medical director of the Parkinson's Disease and Movement Disorders Center at Duke University Medical Center, Durham, N.C. "However, it may be appropriate for doctors to inform patients of this potential risk, particularly in their patients taking relatively high dosages of a dopamine agonist, and with a documented history of depression or anxiety disorder."
The nine patients were taking both levodopa (a drug that the brain transforms into dopamine) and a dopamine agonist (a drug that activates the dopamine receptor in the brain). Eight of the patients took pramipexole as their dopamine agonist, and one patient was on pergolide. None of the other patients taking ropinirole (a different dopamine agonist) or only levodopa were identified with a gambling problem.
Most of the patients were in advanced stages of the disease. On average, they had been diagnosed with Parkinson's for more than 11 years before gambling problems began. The patients were taking pramipexole or pergolide anywhere from six to 64 months before the onset of gambling, and seven patients started gambling within one month of an increased dosage of the dopamine agonist. None of them had a previous history of gambling.
The gambling behavior was severe enough to cause financial problems, and two patients had losses more than $60,000. After a family member or caregiver noticed substantial financial loss, the patients' treatment regimen was changed.
For most patients, the gambling could be controlled or stopped under a new treatment plan. Eight patients had the dopamine agonist switched to lower comparative dosages of ropinirole, and the remaining patient received a decreased dosage of pramipexole and an increased dosage of levodopa. Some patients also attended Gamblers Anonymous meetings. Caregivers secured patients' credit cards and watched for signs of a gambling relapse.
Two of the patients who switched to ropinirole also required additional psychiatric treatment, and one withdrew from the therapy program and later committed suicide, while dealing with a number of issues unrelated to her Parkinson's disease.
The rate of pathological gambling found in the 529 subjects taking pramipexole (1.5 percent) is only slightly higher than the reported rate in the general population (.3 to 1.3 percent), and the availability of casinos in a retirement and vacation setting like Arizona may have contributed to the development of this behavior in the patients, Stacy noted.
"However, this clinical observation suggests that higher dosages of dopamine agonists may be a catalyst to bringing out this destructive behavior," said Stacy.
Dopamine is a chemical substance produced in the brain that enables people to move smoothly. Parkinson's patients have a severe shortage of dopamine, which results in symptoms including tremor, rigidity and walking problems.
The American Academy of Neurology, an association of more than 18,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as stroke, Alzheimer's disease, epilepsy, Parkinson's disease, autism and multiple sclerosis.
For more information about the American Academy of Neurology, visit its website at www.aan.com.