Thanks for the thought provoking post, nowheretorun. I like when people speculate.

For myself, I am moving away from a definition of depression as a disease. It turns out it has not been helpful to me to think of it as a pathology. Now I am seeing that depression has adaptive value. It is so widespread--why would such a condition be so common if it was not evolutionarily advantageous in some way? Humans have evolved such that depression is a part of us. I've been learning about a number of animal studies that look at animal behaviors that are analogs of depression in humans. These behaviors definitely have adaptive value. I am learning to see my own depression as a response to life circumstances that is not without value. I am healthy, even though I have been depressed. My depression is a response to my environment. Sure I can get some degree of relief from meds, therapy, exercise, etc. I have really dug deep through therapy and solved some of the key problems in my life. It has really helped. My biochemistry is changing in response to my changed life events. I'm coming out of it. It feels great! It's definitely 3 steps forward and 2 steps back, but the general direction is right. I am healthy and always have been, whether depressed or not.

I know that won't fit with what a number of people believe, but it's an evolving idea for me, and I don't think has reached its final form yet. I am learning more each day.