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Parkinsonís Disease Itself Does Not Increase Risk of Compulsive Behaviors
- Feb 20 2013
Parkinson’s disease (PD) itself does not increase the risk of impulse control disorders (ICDs) such as compulsive gambling or eating, according to new research published in the January 8 issue of Neurology. The study suggests that certain medications are responsible for increased risk of ICDs in people living with PD.
Previous studies have shown that people with PD who take certain medications, called dopamine agonists, have a higher incidence of ICDs than the general public. This class of drugs includes bromocriptine (Parlodel®); pramipexole (Mirapex®); ropinirole (Requip®); and rotigotine transdermal system (Neupro®). However, doctors have not been sure whether medications are to blame, or whether the disease itself might cause ICDs.
Researchers led by Daniel Weintraub, M.D., at the University of Pennsylvania School of Medicine and the Philadelphia Veterans Affairs Medical Center compared ICD symptoms in two groups: 168 people newly diagnosed with PD who were not yet taking medications, and 143 people of similar ages without Parkinson’s.
All participants completed a questionnaire that asked how often they experienced ICD symptoms such as compulsive gambling, buying, sexual behavior and eating. They were also asked about some related behaviors that are not considered ICDs: aimless wandering, punding (the excessive repetition of trivial tasks, such as handling or sorting objects), and hobbyism (the compulsive pursuit of a hobby such as collecting or Internet usage).
- About 20 percent of each group experienced at least one ICD symptom or related behavior.
- People living with PD were no more likely to experience ICD symptoms or related behaviors than people without the disease.
- People who experienced cognitive issues were no more likely to experience ICDs than those without cognitive issues.
- In both groups, people who were depressed were more likely to experience ICD symptoms.
What Does It Mean?
This study indicates that PD itself does not increase the risk of ICD symptoms or related behaviors. Rather, it is likely that drugs used to treat PD are to blame. Recent studies have pointed the finger at a class of drugs called dopamine agonists.
Dopamine agonists help to replace lost dopamine and are often prescribed early in the disease because they have fewer side effects than the standard treatment for PD, levodopa. They have an important role in the treatment of PD, but the risk for ICDs is a major concern, especially for those with risk factors.
It is important to note that the researchers used a new questionnaire to screen for ICD symptoms, and understand how often they occurred, observing that 20 percent of each group experienced one. However, the questionnaire did not address the severity of symptoms or whether individuals would actually meet the diagnostic criteria for an ICD. Therefore, it is likely that the study overestimated the number of people experiencing true ICDs.
In addition, this study reveals that people with depression, whether or not they have PD, are more likely to report ICD symptoms. Perhaps by screening for and treating depression in people with newly diagnosed PD, doctors could reduce the risk that people will develop an ICD when they begin taking dopamine agonist medication. However, further research is needed to confirm the link between depression and ICD symptoms in people with PD.
Future studies need to try to identify who is at risk of developing ICD under dopamine agonist treatment. If so, doctors may someday be able to predict who is at risk for ICD based on questionnaires or genetic testing (as they do in other medical conditions such as epilepsy). Then they could avoid prescribing dopamine agonist medications to those at risk, or at least use them more cautiously, frequently assessing for this potential side effect.
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Source Date: Feb 20 2013