Somatosensory Cerebral Evoked Responses in Psychotic Depression

¹ Professor of Psychiatry, College of Medicine and Psychopathic Hospital, University of Iowa, Iowa City, Iowa
² Associate Professor, Department of Psychology, University of Cincinnati, Cincinnati, Ohio

Recent methodological developments suggested reasons to doubt the validity of conclusions derived from previous results showing that the amplitude and recovery function of averaged somatosensory cerebral evoked responses differ from normal in patients with psychotic depressions. This study was carried out to verify and extend earlier findings with methods designed to overcome the faults of previous investigations. Somatosensory recovery functions were measured in 21 patients with psychotic depressions and in 21 non-patient controls matched for age and sex. Latency and amplitude were measured for eight peaks in each response. Results confirmed previous findings that recovery of the initial component was less in psychotic depressions that in controls, particularly during the first 20 msec. They did not confirm that responses to unpaired stimuli are larger in depression, suggesting that previous differences may have been due to lack of control for age. Some of the later peaks measured yielded additional statistically significant recovery differences between patients and controls, none of which were as great as that for the initial component. There was some lack of concordance between measures of amplitude and latency recovery for the same peaks, suggesting the operation of different mechanisms. Evoked response characteristics varied considerably with respect to age and sex, emphasizing the need for control of those factors.