Finds that Impulse Control Disorders are Related to PD Medications, Not the Disease Itself
Today, an important milestone for the Parkinson’s Progression Markers Initiative (PPMI), as, for the first time, researchers have published a scientifically-reviewed paper using data culled from the study.
The paper appears in Neurology, the medical journal of the American Academy of Neurology, and it addresses impulse control disorders (ICD) in people with Parkinson’s disease (PD), conditions experienced by about one in five with PD. ICDs can include behaviors ranging from pathological gambling to substance abuse, among others.
Daniel Weintraub, MD, and a team at the University of Pennsylvania found that Parkinson's itself does not confer a higher risk for ICDs, supporting other research that suggests the high prevalence of ICDs in people with PD is related to Parkinson's medications, and not the disease itself.
Weintraub looked at a group of the newly-diagnosed people with Parkinson’s that comprise the PPMI patient population, and compared them with PPMI control volunteers, finding no difference between the groups in terms of prevalence of impulsivity.
But as it’s widely understood that more people with PD have ICDs than the general population, Weintraub and his team will look to learn more about how Parkinson’s drugs might play a role in ICDs. The focus of their research surrounds the dopamine system of the brain, which regulates both movement and impulsivity. The Parkinson’s gold standard drug, called levodopa, is designed to increase the depleted levels of dopamine that cause the motor symptoms of PD, but in so doing, it’s possible that it might also make a person more likely to experience ICDs.
Parkinson’s patients in PPMI have yet to begin levodopa treatment, so the study was able to provide a clear measure of the impact of the disease itself, as well as a baseline for measuring the onset of ICDs in future studies. Weintraub says that he will continue to follow these patients over time, with the goal of predicting how and when exposure to dopamine-related drugs could play a role in ICDs.
An important note, says Foundation staffer Maurizio Facheris, MD, MSc: All drugs work differently for each individual, and ICDs certainly don’t develop in everyone who takes dopamine agonists. These drugs often work quite well, and the majority of those who take them do not develop these specific side effects.
In an unrelated study supported by MJFF, Weintraub is also currently studying whether an existing drug used to treat alcohol dependence called naltrexone might be effective in limiting ICDs in people with PD.