Dopamine dysregulation syndrome in Parkinson's disease

Purpose of review Dopamine replacement therapy in Parkinson's disease ameliorates motor symptoms. However, it has recently been recognized that a small sub-group of patients suffer motor and behavioural disturbances attributable to taking quantities of medication well beyond the dose required to treat their motor disabilities. This review examines the phenomenology of dopamine dysregulation syndrome in relation to the current understanding of basal ganglia function and its impact on longterm management. Recent findings Cortico-striato-thalamic circuits are implicated in the behavioural and motor disturbances associated with compulsive medication use in Parkinson's disease. Advances in understanding of the role of dopamine in psychostimulant addiction are important in helping to understand dopamine dysregulation. Summary Recognition of dopamine dysregulation syndrome and characterization of its phenomenology supports the notion that the medication used to treat Parkinson's disease can disrupt basal ganglia mediated motor and behavioural functioning. Refinement of clinical strategies to predict, identify and manage this syndrome will aid the future treatment of motor and nonmotor complications of Parkinson's disease.