The pertinency of the visual evoked potentials (VEP) was studied as an index of depression in a group of 50 depressed patients (according to DSM III criteria). The VEP recordings were realized before an antidepressive treatment (D0) and 4 weeks after the beginning of the treatment (D28). Identical recordings were realized with 15 healthy and voluntary reference subjects. Stimulations were reversal checkerboard. The analysis of the results indicate at D0 a reduction of P1 and N1 latencies in the depressed people compared to the reference subjects, and an increase of the P1-N1 amplitude. These differences disappear at D28 (after the antidepressive treatment), as we don't notice any significative difference between D0 and D28 with the reference subjects. The interpretation of these results leads to the hypothesis of a neurophysiological modification of the attentional processes during the depression state. The antidepressive treatment seems merely to produce a normalization of the evoked responses in the depressed patients.