One further point about emotions & depressive symptoms whilst fasting, especially in the early stages, is the transfer from glucose as the main energy source to one of fat burning thru ketosis, and which is where low blood Sugar during this transfer has an affect on mood: especially in those individuals who seem to have a greater susceptibility and sensitivity to this transfer which brings on temporary symptoms of Hypoglycemia.
As Shelton and others observed, this is usually only of a transitory nature, and clears as the fast progresses as the body fully adjusts to fat burning as its main energy source.