How Parkinson’s medications may affect behavior

Dopaminergic medications (or medications that enhance the brain’s dopamine system) are the mainstay of treatment for the motor symptoms of Parkinson’s disease (PD). These medications have the potential to dramatically improve the quality of life of someone with PD by improving slowness and stiffness, tremor, and gait difficulties – which are all frequent symptoms of the disease. However, like all medications, they can also cause side effects. Some common side effects of dopaminergic medications include fatigue, dizziness, nausea, and hallucinations. 

Side effects of dopamine agonists

A less common, but well-described set of side effects of dopamine medications are impulsive- compulsive behaviors (ICBs). This group of behaviors includes impulse control disorders (ICDs), dopamine dysregulation syndrome (DDS), and punding, each of which we will discuss below.

Dopamine agonist medications (the three available in the US are: ropinirole (Requip), pramipexole (Mirapex), rotigotine (Neupro patch), and apomorphine (Apokyn)) are most associated with impulse control disorders, and Levodopa is most associated with dopamine dysregulation syndrome.

• These categories of behaviors are related to each other, and they can co-exist in the same person.
• Risk factors for these conditions are younger age, male sex, and history of addictive behaviors.
• One suggested approach is for clinicians to avoid use of dopamine agonists if the person with PD fits this profile.

More about impulse control behaviors and Parkinson’s

Impulse control disorders (ICD) 

Impulse control disorders (ICD) is a set of behavioral abnormalities in which a person is unable to control urges or compulsions. Compulsivity can manifest in many ways, for example, gambling, hyper-sexuality, over-shopping, or over-eating. Compulsivity can be displayed in any activity including work, hobbies, or exercise, so it is important to consider whether the extent that the activity is being conducted is impairing quality of life.

In some cases, the effects of these behaviors can have significant impact on the person with PD and their family. Gambling can lead to financial hardship; over-eating can lead to other health issues; over-exercising can lead to injury, and thus it is important to address these behaviors.

Dopamine Dysregulation Syndrome

Dopamine Dysregulation Syndrome (DDS) is characterized by an addictive use of dopaminergic medications. The person with PD takes more medication than prescribed, meaning more than is needed to objectively treat their motor symptoms. This can lead to severe dyskinesias (involuntary, dance-like movements that are a side effect of levodopa), mania, aggression, or psychosis.

Those who exhibit DDS may demonstrate drug-seeking or addict-like behavior when it comes to their dopaminergic medications. Often, care partners need to secure the medication bottles to ensure that the person with PD takes only the prescribed amount.

The person with PD with DDS may explain that they need to take more levodopa than prescribed to treat non-motor symptoms such as pain or uncomfortable sensations. This may be true, and it these types of non-motor symptoms can develop during an OFF period, when dopamine levels are low and can be treated with more Levodopa. Therefore, it is important to note that not every person who wants to take more levodopa for reasons other than treatment of motor symptoms of PD, has DDS. However, when someone has DDS, the amount of levodopa ingested causes difficulties that impair quality of life.

Punding

Punding refers to a set of complex and repetitive behaviors that involve purposeless activities. These activities may include sorting objects, collecting items, or engaging in repetitive hobbies, such as repeatedly disassembling and reassembling objects. Picking apart tissues or pulling strings on clothing are examples of punding.

• Punding behaviors are generally compulsive and can be time-consuming, leading individuals to neglect other important aspects of their daily lives.
• Unlike ICDs, punding is not driven by pleasure, anxiety, or obsession, but if a care partner tries to disrupt the punding, the person with PD may become irritable.
• Patients with punding may recognize that time and money spent on their behaviors are excessive and inappropriate, but they may not be able to stop.

Predictors of punding in PD include higher doses of dopamine replacement therapy, male sex, and increased disease severity. Various psychiatric co-morbidities have been associated with punding including psychosis, depression, and anxiety. Punding is also more common in people with PD who have cognitive impairment as opposed to those who don’t.

Diagnosing punding can be challenging, as individuals may not always recognize or acknowledge their behaviors as being pathological. Healthcare professionals often rely on what they hear from the person with PD, as well as their observations, and input from family members to identify punding behaviors. A recent journal article gives a very useful overview of punding.

Treatment of impulsive-compulsive behaviors

It is important to address these behaviors as soon as possible with the health care team, as early intervention can lead to improved results.

Adjusting dopaminergic medications is the first line of treatment for ICBs. This may involve tapering off of dopamine agonists or decreasing other dopaminergic medications. Lowering medication to treat ICBs can be challenging because dopaminergic medications are needed to treat the movement aspects of PD. Stopping PD medications altogether to treat an ICB is usually not possible, since the person with PD needs the medication to allow them to move. However, stopping or reducing the dose of the suspected agent can helps.

Particularly when lowering or stopping a dopamine agonist, care has to be taken not to precipitate a withdrawal syndrome. Dopamine agonist withdrawal syndrome (DAWS) occurs when a dopamine agonist is lowered or stopped too quickly and its symptoms include irritability, depression, and even suicidality. People with PD and their care partners should therefore be warned about the possibility of withdrawal when the dose of a dopamine agonist is lowered. Tapering the dose must be done very slowly.

There is not enough data to recommend any other specific treatments, however, various therapies have been reported in the literature with some success. Switching to duopa – a levodopa infusion directly into the small intestine was tried in a small number of cases with some benefit. Other potential treatments have been suggested and these include – amantadine, quetiapine, clozapine and valproic acid. Deep brain stimulation has been reported as helpful in some situations, perhaps because it allows for reduction of dopaminergic medication.

Always speak with your doctor about any symptoms you are having, and never adjust your medication dosing or schedule without consulting your doctor.

Tips and Takeaways

• Impulsive-compulsive behaviors in PD include impulse control disorders, dopamine dysregulation syndrome, and punding.
• It is important to address these behaviors as they can have a significant impact on quality of life, finances, personal health and safety, and more.
• These behaviors are often treated with changing dopaminergic medication.
• It is important that any medication change is done slowly and in consultation with your doctor.