"The Sound of Fear": assessing vocal fundamental frequency as a physiological indicator of social anxiety disorder.

The relationship between vocal pitch and social anxiety disorder (SAD) has been examined with encouraging initial results, highlighting increased fundamental frequency (F0) as a physiological indicator of SAD. The present series of studies examined the relationship between F0 emitted during social threat and SAD symptoms. Two independent samples of SAD patients, and a sample of demographically-equivalent non-socially anxious controls (NSACs), completed varying social threat tasks which involved speech. Mean F0 emitted throughout the tasks was examined. Male SAD patients emitted greater F0 in comparison to NSACs across studies. For females, this relationship was significant only when examined in patients with SAD of the generalized subtype, and in response to in vivo social exposures. Furthermore, gender-specific thresholds for overall F0 emitted during social threat were identified which demonstrated excellent differentiation between patients with generalized SAD and NSACs. These results provide additional support for increased F0 as a physiological indicator of SAD.