Here is a book I'm in the process of reading on our favorite subject: "Why People Get Sick: Exploring the Mind Body Connection" by Darian Leader and David Corfield, 2008. Interesting, very psychoanalytically oriented.
I'm certain it's interesting and valid. Though i tend to stay away from such books because they always set off a cycle of worrying about the unhealthy effects of worrying etc...
Fear of fear is a very difficult vicious cycle to break...