Complex sentence: Dopamine dysregulation syndrome (DDS), sometimes known as hedonistic homeostatic dysregulation in Parkinson's disease, is a dysfunction of the reward system in subjects with Parkinson's disease (PD) due to a long exposure to dopamine replacement therapy (DRT).
Split into simpler sentences: Dopamine dysregulation syndrome (DDS) is a dysfunction of the reward system observed in some individuals taking dopaminergic medications for an extended length of time. It can occur in subjects with Parkinson's disease (PD) due to a long exposure to dopamine replacement therapy (DRT).