I came across a article on a science website stating that some researches may have discovered a solution to block a stress related hormone to regrow some hair. (Testing on animals currently)
I know that alopecia is a autoimmune disease, though a lot of people agree stress plays a major role, its successful on mice, if its successful on humans, then maybe this can help one day in some sort of treatment.
http://www.sciencedaily.com/releases/2011/02/110216185406.htm