The objective of the current cross-sectional study was to use standardized psychiatric interviews (the Structured Clinical Interview for DSM-IV Axis I Disorders and the Neuropsychiatric Inventory; NPI) in order to better characterize psychiatric symptoms in 50 consecutive, treated and clinically stable patients with Wilson's disease (WD). Nine patients (18%) had one, 7 patients (14%) had two, and 20 (40%) had >or= 3 neuropsychiatric symptoms present. The most often endosed symptoms were anxiety (62%), depression (36%), irritability (26%), as well as disinhibition and apathy (24% each). Twenty two patients (44%) had a score >or= 4 on at least one of the NPI items: again, most frequently anxiety (17 patients; 34%), depression (13 patients; 26%) and apathy (9 patients; 18%). Therefore, even among stable, long-term treated patients with WD approximately 70% experienced psychiatric symptoms.