Objective Evaluation of Antidepressant Therapy by Conditional Reflex Technique

Abstract

Certain clinical and physiological observations in patients suffering from depression suggested the interpretation that depression may be a state of inhibition resulting from supramaximal excitation (1, 2). This hypothesis was put to a test by means of the Pavlovian conditional reflex technique as elaborated in Dr. W. Horsley Gantt’s laboratory (3, 4), utilizing his method of spacing and alternation of different stimuli. The stimuli and the responses were recorded continuously on a 5-channel Grass polygraph, as described previously (5). The results of our study confirmed the hypothesis. It was found (5–8) that the capacity to form conditional reflexes was significantly reduced in patients suffering from depression. The conditional psychogalvanic reflex showed reduction in magnitude and delay as well as impairment of differentiation between the excitatory and inhibitory stimuli, including paradoxical reversal of the responses in that inhibitory stimuli evoked greater responses than excitatory stimuli. (Pavlov’s Paradoxical-Ultraparadoxical Phase.)