Is writing a cure for depression?

I just read something in a book about writing that surprised me. It was claiming that writer's need to write as a let off for steam, if not their depression, at least as a physiological need. I'm wondering if that's really going to work for me, so, here I go with my daily blog which I will attempt every day. I'm mostly a politically humorous type, but I denfinately want to expand my horizons and blog my heart out.

My thoughts on the book and its claim about writing curing the blues: does that include fingerpainting? Did the guy from My Left Foot get his depression cured because he wrote with his toes? How about Hitler writing Mein Kampf from a prison cell? Was he a depressed personality or what? Then there's the multitude of people that are drooling at the mouth sitting in the asylums of the world. Do they know how to write? Sometimes this is better than zoloft, but other times I'm gonna reach for the pill.