Neuropsychological aspects of impulse control disorders in Parkinson's disease

Impulse control disorders (ICDs), such as excessive gambling, compulsive sexual behavior, binge eating, compulsive shopping as well as punding, and the dopamine dysregulation syndrome, may arise as a debilitating neuropsychiatric complication in Parkinson's disease (PD). Although the pathophysiology is not fully understood, it likely involves mesolimbic dopaminergic overstimulation combined with disease-related vulnerabilities in reward, motivation, and inhibitory control networks. This narrative review summarizes evidence on the neuropsychological, affective, and behavioral traits associated with ICDs in PD, with a particular focus on epidemiology/clinical manifestations, neurobiological and pharmacological mechanisms, as well as prevention and management strategies. ICDs can affect up to 40% of PD patients and are strongly associated with dopamine agonist exposure, younger age of onset, premorbid personality traits, and neuropsychiatric comorbidities. Neuropsychological findings reveal abnormalities in several domains, including reflection impulsivity, temporal discounting, novelty seeking, risk processing, and inhibitory control, while mood disorders, sleep dysfunction, apathy, and anxiety further influence vulnerability and worsen behavioral dysregulation. Although general awareness for development of ICDs has been raised, they still represent a significant burden for patients and their family members and are a predictor of functional decline and lower quality of life. Management includes dopamine agonist withdrawal whenever possible, the cessation of fast acting dopaminergic agents and treatment of neuropsychiatric comorbidities. In selected cases, deep brain stimulation or continuous dopaminergic delivery should be considered, particularly in those experiencing persistent worsening of motor symptoms despite appropriate adjustment of dopaminergic medication.