Medications, Deep Brain Stimulation, and Other Factors Influencing Impulse Control Disorders in Parkinson's Disease

Abstract

Impulse control disorders (ICDs) in Parkinson's disease (PD) have a high cumulative incidence and negatively impact quality of life. ICDs are influenced by a complex interaction of multiple factors. Although it is now well-recognized that dopaminergic treatments and especially dopamine agonists underpin many ICDs, medications alone are not the sole cause. Susceptibility to ICD is increased in the setting of PD. While causality can be challenging to ascertain, a wide range of modifiable and non-modifiable risk factors have been linked to ICDs. Common characteristics of PD patients with ICDs have been consistently identified across many studies; for example, males with an early age of PD onset and dopamine agonist use have a higher risk of ICD. However, not all cases of ICDs in PD can be directly attributable to dopamine, and studies have concluded that additional factors such as genetics, smoking, and/or depression may be more predictive. Beyond dopamine, other ICD associations have been described but remain difficult to explain, including deep brain stimulation surgery, especially in the setting of a reduction in dopaminergic medication use. In this review, we will summarize the demographic, genetic, behavioral, and clinical contributions potentially influencing ICD onset in PD. These associations may inspire future preventative or therapeutic strategies.

Keywords: Parkinson's disease; deep brain stimulation; dopaminergic medications; impulse control disorder; impulsivity.

Figure 1

The most common impulse control disorders (ICDs) in Parkinson's disease include hypersexuality, compulsive shopping, binge eating, and pathological gambling. ICDs are associated with hypersensitivity to reward and uncontrollable repetitive behaviors, leading to an impaired quality of life.

Figure 2

There are many established risk factors for impulse control disorders (ICDs) in Parkinson's disease (PD), including demographics, personality traits, genetic predisposition, depression, tobacco/alcohol use, age of disease onset, dopaminergic medications, and deep brain stimulation (DBS). Several other risk factors under investigation are not depicted.

Figure 3

Cultural and environmental factors may influence ICD risk, as rates of impulse control disorders (ICDs) in people with Parkinson's disease (PD) around the world are highly variable (see Table 1 and text). Further studies are needed that investigate ICD rates in South America, Africa, and areas in Europe and Asia.