Autonomic activation and endogenous depression

Psychophysiologic parameters were investigated in 10 patients with endogenous depression during the course of electroconvulsive therapy. Changes in the depressive mood were assessed by the patients at regular intervals using a general mood scale. EEG and heart rate response and habituation were recorded before, during, and after E.C.T. Prior to treatment a low variance and responsiveness and striking intra-individual stability were found in the physiologic parameters. At the start of E.C.T. there was a significant increase in the deviation values of heart rate and a significant increase in the occurrence of typical biphasic heart rate responses. The EEG showed increased amplitudes and a slowing of background activity. Treatment-dependent differences were also seen in the habituation of the EEG amplitude response. Regarding improvement in the depressive mood, differences were found between the retarded and the agitated patients. Agitated patients demonstrated a continous gradual decline of their depressive condition, while in retarded patients the general trend toward improvement passed through a period of increased mood lability. The results are interpreted with reference to the activation dependency of heart rate responses.