VISUAL COGNITIVE DYSFUNCTION IN DEPRESSION - AN EVENT-RELATED POTENTIAL STUDY

The P3(00) event-related potentials (ERPs) elicited by visual stimuli in two visual tasks were assessed in depressed patients (12 patients w ith major depression and 11 patients with bipolar disorder) and compar ed with those of 20 age matched normal controls. At remission, the ERP s from 18 of the depressed patients were again recorded. The visual od dball (VO) paradigm presented both target and standard visual stimuli and the simple visual (SV) paradigm presented a target but no standard visual stimulus. Subjects performed the VO task significantly less ac curately than the SV task, as reflected by the behavioral measures (re action-tirne and task accuracy). Depressed patients of the bipolar gro up showed longer P3 peak- latency for the VO task and no change in P3 amplitude. No significant differences were found in any other ERP comp onent between the groups. During remission, slowing RTs and reduced P3 peak latencies were observed for both major depression and bipolar di sorder groups. Thus, the P3 ERP may be an index of the contribution of the slowed central processing to psychomotor retardation in clinicall y homogenous samples of depressive patients performing an appropriatel y demanding task. (C) 1998 Elsevier Science Ireland Ltd. All rights re served.