Vanderbilt University researchers may have found a clue to the blues that can come with the flu - depression may be triggered by the same mechanisms that enable the immune system to respond to infection.In a study in the December issue of Neuropsychopharmacology, Chong-Bin Zhu, M.D., Ph.D., Randy Blakely, Ph.D., William Hewlett, M.D., Ph.D., and colleagues activated the immune system in mice to produce "despair-like" behavior that has similarities to depression in humans
Odd but interesting notion. There is also research that links strep infections and OCD.