Impulse control disorders in Parkinson's disease: definition, epidemiology, risk factors, neurobiology and management

There is increasing awareness that impulse control disorders (ICDs), including pathological gambling, hyper-sexuality, compulsive eating and buying, can occur as a complication of Parkinson's disease (PD). In addition, other impulsive or compulsive disorders have been reported to occur, including dopamine dysregulation syndrome (DDS) and punding. Case reports and prospective studies have reported an association between ICDs and the use of dopamine receptor agonists at higher doses, and DDS has been associated with L-dopa at higher doses or short-acting dopamine receptor agonists. Risk factors for ICDs include male sex, younger age or younger age at PD onset, a pre-PD history of ICD symptoms, history of substance use or bipolar disorder, and a personality profile characterized by impulsiveness. The management of clinically significant ICD symptoms should consist of modifications to dopamine replacement therapy, particularly dopamine receptor agonists, which is usually associated with an improvement of ICDs. There is no empirical evidence supporting the use of psychiatric drugs for ICDs in PD. Functional neuroimaging studies such as functional MRI and PET can investigate in vivo the neurobiological basis of these pathological behaviours.