The pathophysiology of impulse control disorders in Parkinson disease

Aims: This review aims to evaluate the most recent evidence on the pathophysiology of impulse control disorders (ICDs) in Parkinson disease (PD). Methods: Computerised searches of Medline, Embase and PsycInfo, along with manual searches for grey literature, were conducted and resulted in a total of 16 studies suitable for review. Results: Evidence was divided into four categories: medication used in PD management, imaging studies, genetic analysis and subthalamic deep brain stimulation (STN-DBS). Analysis of the literature reveals that both intrinsic and extrinsic factors may play a role in the pathophysiology of ICDs in PD. Dysfunction of the mesocorticolimbic pathway and polymorphisms of the dopamine D3 and D4 receptors may increase an individual's susceptibility to the development of ICDs. Discussion: Dopaminergic medication, particularly dopamine agonists (DAs), increases the risk of developing impulsive behaviours in a PD patient. Further evidence, particularly in the form of prospective studies and randomised controlled trials is required to better establish the pathophysiology of ICDs in PD.