Hi Adam ~ I too have "major depressive disorder" or clinical depression, and I know you said you don't buy into the chemical imbalance thing -- but believe me, it sure has made a difference for me!
I've been depressed since I was a very small child -- about 4 or 5. I didn't get treatment until I was in my 20's. So as I child, I isolated most of the time, staying in my room with the lights off. When I finally did get therapy my psychiatrist said that of course I needed therapy, but that I also needed medication! So I've been on medication for 40 years - and it's made a world of difference. I did go off at one time, and I immediately sank into the pits of hell! I never want to do that again.
So I do think there are those of us who do have an imbalance. Without meds, I'm just "off the charts."
I hope they put you on something that works! You've been suffering for a long time! God bless and keep us posted. Hugs, Lee