Vocal indicators of mood change in depression

In the framework of a major longitudinal study of depressive disorders, 11 female and 5 male depressives were audio-video-recorded while speaking with clinical interviewers. For selected utterances during depressed and recovered mood states several voice and speech parameters were obtained, using digital analysis techniques. As predicted, the results showed that an increase in speech rate and a decrease in pause duration are powerful indicators of mood improvement in the course of therapy (remission from depressive state). In female but not in male patients, a decrease in minimum fundamental frequency of the voice predicted mood improvement. These effects are discussed with respect to neurophysiological, cognitive, and emotional factors that have been suggested in the literature as possible causes for the patterns of motor expression observed in depressives. The data also point to the urgent need to systematically study gender differences in depressive speech behavior.