Compared to 30 healthy controls, 59 drug free patients with primary major depression exhibited significantly higher rates of heart beat, respiration, and eye blinking; longer simple and associative reaction times; fewer spontaneous fluctuations of skin resistance, a lower salivation rate, a faster habituation rate of skin resistance orienting response, and a smaller CNV area in the EEG. Skin resistance level, speech pause time, N1P2 amplitudes of acoustically evoked potentials and the postimperative negative variation (PINV) in the EEG did not differ between groups. All deviations are nosologically unspecific; they can be regarded as signs of overarousal, as deficits, or as the result of protective inhibition. In all subjects the investigation was repeated twice, while the patients were treated with either amitriptyline or oxaprotiline, repetition of measurement influenced several variables, but most patient/control differences remained unaffected--irrespective of the drug applied.