[Dexamethasone suppression test and endogenous components of evoked potentials in depressed subjects]

P300 and Dexamethasone Suppression Test (DST) have been carried out on 60 depressed patients classified according to the DSM-III and compared to controls. DST discriminated with a high specificity (85%) and sensitivity (80%) melancholics from controls and from other groups of depressed patients: post-dexamethasone cortisol levels were significantly higher in the former. The amplitude of P300 was significantly smaller in depressives as compared to controls. This was more pronounced in the melancholic group but was not specific to them. On the other hand, correlation analyses showed that the weaker the P300 amplitude, the higher the score at the Hamilton Rating Scale for Depression [Acta psychiat. belg., 87, 694-703 (1987)].