Aberration in hearing one's own voice can cause not only stuttering but also depression.

The etiology of depression has not yet been defined with certainty. The successful use of botulinum toxin recently to treat depression has brought to attention the theories which connect emotions with facial muscles. According to facial feedback hypothesis, facial muscles not only express emotions but also cause and/or alter them. It has been long suggested that a disturbance in the process of hearing one's own voice can negatively affect the functioning of vocal muscles, and I suggest that the negative effect can extend to facial muscles leading at the end to depression. Using certain methods to restore the normal function of both vocal and facial muscles can hypothetically be a new treatment for depression.