Part 1, what is depression (NOT the DSM IV view!)
Depression has been termed, in the psychology field, as "learned helplessness"  or "anger (pain) turned inward".  Those are terms from the psychology field, which have their use there. 

However, as nifty as those terms are, I find that they miss the cure.  

First lest start with what Depression is. 

It is a natural and normal response.  It has been shown to be good, in the wild.  I also find that the body has a wisdom that we don't always understand at first. [Monkey citation]

Depression is more than just a mind condition, or even worse view, a imbalance of a single chemical in the brain (serotonin).  In fact, there is a growing body of evidence, that while SSRI's and the like are the routine and "choice" commercial treatment for Depression, they are far from the theoretical ideal.   They have discovered that there are 20x the number of serotonin receptors in the gut than there are in the brain.  which leads me to the question of what is really going on when people respond to SSRI's. 

Stepping away from the current "generic" explaination that Depression is a Mind-Chemical imbalance, I see that the solution lays much deeper.   I say that it's a natural, though unpleasant, coping response of the body (and spirit).

Unlike, medicine, I have a treatment, a cure.  It requires no money, no special tools or chemicals or drugs.  However, it does require one thing, for the person to make a fundemental change: to surrender that sense of their being that finds that life some how satisfying, to allow a part of their life to just go away, like leaves in the wind.  Somewhere in your life is something telling you must participate in a "game" in which only feel crappy.   You MUST set up your life so that you no longer what to participate in that horrible "game",  that pattern that just brings you down.   Some times this can be no longer listening to those we love, who really are trying to give us their best advice, but it simply doesn't work for us.  To step away from Depression, you must find where you are trying to stuff a square block into a round hole.