A random sample of 1,449 PD outpatients was clinically characterised by office-based neurologists, including impairments of activities of daily living (ADL with the Unified Parkinson's Disease Rating scale (UPDRS subscale II) as well as regarding the presence of dementia according to DSM-IV criteria and the Mini-Mental State Exam (MMSE). Depression was screened for with the Montgomery-Asberg Depression Rating Scale (MADRS)