I received "Spontaneous Happiness" by Andrew Weil, MD for free from http://www.goodreads.com/. You would think this book is about happiness, but really it is about depression or rather, ridding oneself of depression. The first several chapters of the book are about emotional well being, depression, and psychological knowledge of emotions. It then goes into methods of becoming happy both with and without the use of prescribed drugs. The author connects physical health with emotional health and shows the relationship as well as how curing one form of helps the other. It ends with a program to follow relating all his methods for maximum happiness.
I have read Weil before "Eating Well for Optimum Health" during a time when I had a foot injury with severe pain. I had had the pain for about 9 months with no amount of pain reliever helping. When I read his book on health he claimed that the pain was caused by inflammation and gave diet adjustments that would help. I tried it and it worked. Currently, I do not suffer from depression. However, from past experience with Weil and his methods, I would bet that his methods for relieving depression would help as well.