Effects of selective attention on visual evoked potentials in depressed patients and healthy controls

The study of the attention process during depression has been realized with the recording of visual evoked potentials (VEP) by simple pattern reversal checkerboard, and in sequences where a rare stimulus appears randomly, with of without task. The recordings obtained on fifty patients before antidepressive treatment (D0) have been compared to the VEP obtained on the same patients at the end of the treatment (D28) and to those obtained on fifteen reference subjects. The results indicate that some perturbations, characteristic of the depressive state, should happen at both levels of attentional selection, early (components P1 and N1) and late (component P3). The responses of the depressive patient appear to reflect rather the intervention of automatic attention process. Electrophysiological and behavioral data seem to indicate a positive effect of the psychotropic treatment.