Impulsivity Issues Not Caused by Parkinson’s Disease Itself

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PHILADELPHIA — About 20% of Parkinson’s disease (PD) patients experience impulse control disorder symptoms, but, according to a new study, the disease itself is not the cause of excessive gambling, shopping or other impulsivity symptoms.1

In fact, untreated Parkinson’s patients are no more likely to face those problems than those without the disease, according to research from the the Philadelphia VAMC and the Perelman School of Medicine at the University of Pennsylvania. The study was published earlier this year in the journal Neurology.

“When looking at newly diagnosed Parkinson’s patients who had yet to be treated with drugs targeting the dopamine system, we saw no difference in impulsivity than what we found in healthy people without the disease,” said lead study author Daniel Weintraub, MD, of the VA’s Parkinson’s Disease and Mental Illness Research, Education and Clinical Center in Philadelphia. “Now, knowing that the disease itself is not driving impulsive behaviors, we can follow newly diagnosed patients over time to see if we can predict how exposure to dopamine-related drugs and other factors play a role in impulse control disorders.”

Researchers used baseline data from 168 newly-diagnosed, untreated Parkinson’s disease patients and 143 healthy control subjects, obtained upon enrollment into the Parkinson’s Progression Markers Initiative (PPMI) to reach their conclusions. They also found that there was an increasing severity of depression associated with impulse control disorders among both groups, particularly with the presence of compulsive eating symptoms.

Frequencies of impulse control and related behavior symptoms for patients with PD vs. the control group members were:

  • gambling (1.2% vs. 0.7%),
  • buying (3.0% vs. 2.1%),
  • sexual behavior (4.2% vs. 3.5%),
  • eating (7.1% vs. 10.5%),
  • punding [compulsive fascination with and performance of repetitive, mechanical tasks] (4.8% vs. 2.1%),
  • hobbyism (5.4% vs. 11.9%),
  • walkabout [aimlessly walking or driving] (0.6% vs. 0.7%), and
  • any impulse control or related behavior (18.5% vs. 20.3%).

“In multivariable models, a diagnosis of PD was not associated with symptoms of any impulse control or related behavior (p ≥ 0.10 in all cases),” the researchers wrote.

The study was the first to use an impulse control assessment tool developed and validated for use in Parkinson’s disease. It also was unique in enrolling both Parkinson’s patients and healthy controls concurrently, as well has having both groups undergo an identical assessment process.

“PD itself does not seem to confer an increased risk for development of impulse control or related behavior symptoms, which further reinforces the reported association between PD medications and impulse control disorders in PD,” the authors wrote. “Given that approximately 20% of patients with newly diagnosed PD report some impulse control or related behavior symptoms, long-term follow-up is needed to determine whether such patients are at increased risk for impulse control disorder development once PD medications are initiated.”

Weintraub said those patients who already show impulse control issues when beginning treatment, should be monitored over time. “For those with Parkinson’s who screened positive for impulse control disorders at baseline, it will be interesting to follow the patients to see if treatment with dopamine agonists and other therapies will further increase risk over time,” he said.

  1. Weintraub D, Papay K, Siderowf A; Parkinson’s Progression Markers Initiative. Screening for impulse control symptoms in patients with de novo Parkinson disease: a case-control study. Neurology. 2013 Jan 8;80(2):176-80. doi: 10.1212/WNL.0b013e31827b915c. PubMed PMID: 23296128; PubMed Central PMCID: PMC3589192.

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