Neuropsychiatric symptoms are common in basal ganglia disorders and may have severe clinical consequences. The authors compared the neuropsychiatric manifestations of patients with Parkinson's disease (PD) and progressive supranuclear palsy (PSP). All 103 PD patients and 27 of the 61 PSP patients were taking dopaminergic agents. PSP patients showed significantly more apathy and disinhibition. Patients with PD had higher frequency of hallucinations, delusions, and depression. These results suggest that PSP patients show symptoms compatible with lesioned orbitofrontal and medial frontal circuits, such as disinhibition and apathy, whereas PD patients show symptoms associated with monoaminergic disturbances, such as psychosis and depression.