P300 subcomponents reflect different aspects of psychopathology in schizophrenia

Background: The aim of the study was to investigate abnormalities of P300 s ubcomponents in schizophrenic patients as well as relationships between the se subcomponents and positive versus negative schizophrenic symptoms. Methods: Nineteen schizophrenic patients and 19 healthy controls were teste d with an auditory event-related potential oddball paradigm designed to eli cit the P300. The P300 data were analyzed by separating P300 subcomponents with a recently developed dipole source model. Results: Compared to healthy controls, schizophrenic patients showed reduce d P300 amplitudes of the temporo-basal dipoles, corresponding mainly to P3b . Positive symptoms of the Positive and Negative Syndrome Scale correlated positively with the temporo-basal but not with temporo-superior dipole P300 activities, whereas negative symptoms correlated positively with the tempo ro-superior but nor with temporo-bar;al dipole activities. Conclusions: The P300 subcomponents separated with the dipole model are aff ected in a different manner by positive versus negative symptoms. Furthermo re, the positive correlation between the severity of psychopathology and th e P300 amplitudes of the different dipole activities appears to be a state- dependent effect, which has to be separated from the P300 amplitude reducti on as a trait marker in schizophrenic patients. Biol Psychiatry 1999; 45:11 6-126 (C) 1999 Society of Biological Psychiatry.