Impulse Control Disorders

Some medications used to treat Parkinson’s disease (PD) may cause impulsive behaviors as a side effect. Impulse control disorders (ICDs) are behavioral disorders in which the person acts out repetitively, excessively, and compulsively in ways that interfere with major areas of life functioning.1,2

ICDs are typically, but not always, associated with treatment with dopamine agonists. Dopamine agonists are a class of medications that are used to treat the motor symptoms of PD. Symptoms of PD, particularly the motor symptoms, are related to a depletion of dopamine in the brain. Dopamine is the neurotransmitter, or chemical messenger, that is responsible for producing smooth, purposeful movement. Dopamine agonists mimic dopamine. Binding of the agonist to a receptor, a protein on the neuron that responds to dopamine, initiates signals in the neuron that can activate motor behaviors. There are many receptors that respond to dopamine and agonists can be designed to specifically activate those receptors that play more of a role in motor behaviors. Activation of these receptors provides relief from symptoms of PD, but may cause side effects, such as impulse control disorders.2,3

These side effects tend to occur in people whose PD is more advanced and who are taking high doses of medications for their PD; however, it can occur at any stage of the disease. Impulsive behaviors often begin when a new medication is added to a treatment regimen or when the dosage of a medication is increased. Any side effect, including impulsive behaviors, should be brought to the attention of a healthcare professional.1

Common impulse control disorders in Parkinson’s disease

ICDs usually are in contrast to how a person would have acted before PD. The most common ICDs seen in people with PD include:

  • Excessive shopping
  • Unusual or increased sexual behavior
  • Compulsive or pathological gambling
  • Compulsive eating (binging)
  • Excessive use of computers
  • Reckless generosity
  • Hoarding
  • Compulsive “hobbying,” including sorting of objects, gardening, writing, craft-making, etc.
  • Aimless wandering

These behaviors can vary in their severity between patients, but they all can lead to devastating consequences, including financial ruin, divorce, loss of employment, and increased health risks. ICDs are associated with greater functional impairment, decreased quality of life, and an increased burden to the caregiver or care partner.1

Risk factors for impulse control disorders in Parkinson’s disease

Not every patient who gets treated with dopamine agonists develops ICDs. Researchers have identified possible risk factors that increase the likelihood of developing ICDs, including:

  • Male gender
  • Younger age of patient
  • Younger age of onset of PD
  • History of ICDs prior to PD diagnosis
  • Personal or family history of substance abuse, bipolar disorder, or gambling problems1

Treating impulse control disorders in Parkinson’s disease

People with PD or their care partners may be reluctant to talk about ICDs due to embarrassment or lack of awareness that they may be connected to the PD medications. However, it is critical that side effects such as ICDs are reported to a healthcare professional for proper management. If the ICDs are related to the use of dopamine agonists, the dopamine agonists may be reduced or discontinued. Other drugs that have shown promise in reducing ICDs in clinical trials include zonisamide, amantadine, topiramate, and valproate.3

Written by: Emily Downward | Last reviewed: March 2017
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