Speech characteristics as indicators of depressive illness.

Measures of the rate of change of voice fundamental frequency, fundamental frequency variability, reading and counting times, and different measures of pause time were compared in 28 depressed patients and 13 healthy controls. The fundamental frequency variables were lower in the depressed group, and the pauses between the interviewer's questions and the patient's answers were longer. The remaining speech variables, including the summed duration of interdigit pauses in counting from 1 to 10 (speech pause time), did not differ between the groups.