Abstract
Little is known about the neurophysiology of anxiety and depression, although these affective states are recognized as perhaps the most outstanding problems in psychopathology.* To advance research in this field, there is need for neurophysiological methods which will provide data bearing on the affective state of the intact human subject. The present study is concerned with the validity of one method which seems suitable for this purpose. Several recent investigations have suggested that the effects of intermittent photic stimulation on the EEG may provide important neurophysiological correlates of emotional states. In most persons, certain flicker rates will elicit rhythmic EEG activity at the flicker frequency; this is called "photic driving." Walter and Walter2observed that photic driving varied with changes of mood in certain subjects. Ulett, Gleser, Winokur, and Lawler3carried out careful quantitative studies of photic driving in relation to anxiety. Employing automatic frequency analysis, they were