In an attempt to differentiate neurophysiologically between major subcategories of psychiatric illness, averaged visual evoked responses (AER) to four intensities of light and kinesthetic figural aftereffects tasks were completed by neurotic depressed, psychotic depressed, schizophrenic, and normal control subjects.
Psychotic depressive patients (unipolar depressed) showed greater variability and augmentation compared to the other subgroups. The relative augmentation was manifest in both AER and in kinesthetic figural aftereffects. The neurotic depressed group could not be distinguished from the normal control group on the basis of neurophysiologic studies.
These findings are discussed in light of some previous studies of bipolar and unipolar depressed subjects which taken together indicate unipolar depressed subjects are augmentors but not extreme augmentors as the bipolar group.
Borge GF. Perceptual Modulation and Variability in Psychiatric Patients. Arch Gen Psychiatry. 1973;29(6):760-763. doi:10.1001/archpsyc.1973.04200060046006