[The influence of suicide risk and despondency on the amplitude of P300 in major depression].

P300 amplitude represents a useful tool to assess information processing in normal and psychopathological subjects. In depressive disorders, many studies have shown a decrease of P300 amplitude and an increase of its latency. However, functional significance of the P300 modifications remain unclear. The aim of the study was to assess the influence of suicidal risk and hopelessness on P300 amplitude among 40 depressive inpatients. The results showed significant relationships between P300 amplitude and suicidal risk (r = -0.68, p < 0.001) and with hopelessness (r = -0.76, p < 0.001). From a clinical point of view, P300 amplitude should be considered as a psychophysiological index of suicidal risk in major depressive disorder.