Medicines are a key part of managing the symptoms of Parkinson’s disease (PD). However, some medicines may cause unpleasant side effects like impulse control disorders (ICDs).
ICDs are disorders in which someone acts out repetitively, excessively, and compulsively in ways that impact major areas of life.1,2
What causes ICDs?
ICDs can occur in any person with PD regardless of current treatment. However, ICDs are most often triggered by a kind of drug called a dopamine agonist. They are a type of drug that are used to treat the movement symptoms of PD. Symptoms of PD, especially the motor symptoms, are related to a lack of dopamine in the brain.2,3
Dopamine is the chemical messenger that is responsible for producing smooth movement. Dopamine agonists mimic dopamine. They work by binding to a receptor in the brain. The receptor is a special protein in the brain that responds to dopamine.
This helps start signals in the brain that activate movement. Activation of these receptors helps relieve symptoms of PD. However, dopamine agonists may cause side effects, including ICDs.1,2,4
The parts of the brain that are involved in feelings of reward are also controlled by dopamine. It is believed that dopamine agonists can also impact these parts of the brain, which may trigger impulsive behaviors. ICDs tend to occur in people with more advanced PD and those taking high doses of dopamine agonists. 1
However, it can occur at any stage of the disease. Impulsive behaviors often begin when a new medicine is started or when the dosage is increased. Tell your doctor about any new side effects, including impulsive behaviors.1,5
What are the symptoms?
ICD behaviors are usually very different from how a person would have acted before PD. The most common ICDs seen in people with PD include:1-5
- Excessive shopping
- Unusual or increased sexual behavior
- Compulsive or excessive gambling
- Compulsive eating (binge eating)
- Excessive use of computers
- Reckless generosity
- Hoarding
- Compulsive "hobbying," like sorting of objects, gardening, writing, craft-making, etc.
These behaviors can vary in their severity in different people. In some cases, they can just be a slight inconvenience. For others, they can lead to serious consequences. These include financial problems, divorce, loss of employment, and increased health risks.1,5,6
Risk factors in Parkinson’s
Not every person who gets treated with dopamine agonists develops ICDs. Researchers have identified possible risk factors that increase the likelihood of developing ICDs. People who may be more likely to develop ICDs include:1,5
- Men
- Younger people with PD or people who were younger when they received a PD diagnosis
- History of ICDs before a PD diagnosis
- Personal or family history of substance abuse, bipolar disorder, or gambling problems
Treatment options
If you notice an impulsive behavior, the first step is to tell your doctor. People with PD may be reluctant to talk about ICDs due to embarrassment. Many people also do not realize the connection to PD medicines.1,6
If the ICD is related to dopamine agonists, the best treatment is to adjust the medicine. This may mean lowering the dose or switching to a new PD drug. It is important to never stop taking a dopamine agonist suddenly. The dose needs to be slowly reduced to prevent withdrawal.1,6
Caregivers can also take steps to prevent the consequences of ICDs. This includes restricting access to credit cards or the internet. These steps do not cure ICDs but can help prevent serious outcomes.1,6