An auditory psychophysical correlate of depression

Abstract

In this study, we examine the possible relation between depression and a diminution of subjective pleasure experienced during sensory stimulation. A subjective evaluation of 5 pure sounds presented at random 5 times to each subject was carried out with 10 depressive subjects, 10 non-depressive psychiatric subjects, and 10 non-depressive subjects, the three groups being matched for sex and age. In depressed subjects, the results showed no reduction in the number of experiences of subjective pleasure but a significant reduction in the repeatability of subjective pleasure associated with a given sound. These modifications seems to be specific to depression since psychiatric patients receiving neurotropic drug behave as control subjects. On the other hand, no such significant difference is found in the repeatability of a subjectively unpleasant experience. Finally, when all subjects are considered on the same continuum of depression, a significant negative correlation is found ( P < 0.01) between the degree of depression as measured by the Beck Depression Inventory and the number of sounds for which repeatability of subjective pleasure is obtained over 5 trials. Our results extend into the sensory realm the reduction in the repeatability of subjective pleasure already established for depressed subjects in the social realm; this is discussed in terms of positive reinforcement reduction associated with depression.