As depression is just a label for a collection of symptoms (both physical and emotional), I guess it doesn't really matter if the origin of these symptoms is biological or anthropogenic, internal or external, self inflicted or circumstantial. The experience of depression is what matters to the person who is living with it.

I am at a stage now where the symptoms are overpowering me and the medical profession either can't or won't help. Believing that depression is an illness that can be treated and will get better is very far from my experience, yet it is what I've always believed. Right now, my personal view is that depression is my punishment for being such an incompetent and worthless person.

I think I'm saying in a roundabout way, I relate.