I understand. But I was responding more directly to ksen's comment:
He said: My pastor holds the view the Psychology only exists to help us deal with the GUILT of our sin and not the sin itself.
So I don't think, in response to that statement, it really matters whether it was "clinical depression" or "low self esteem."
I do believe there is a difference between psychology and psychiatry. One is a medical science and the other is not.
With all due respect, if your depression was indeed sin and not medically induced, I'd like to suggest the possibility of it being the sin of unthankfulness. I am persuaded that unthankfulness is the key ingredient behind all depression. Repentence and thankfulness to God are the true remedies. I know it's a hard pill to swallow when dealing with a crisis such as cancer, but even then, a grateful heart inclined to rest in the Providence of God will vanquish depression.