Very well written! I'm both a Psychology Student and I personally suffer with depression.

I'd like to also comment on the Biopsychosocial model, not sure if you have heard of it, from your extensive understanding, you may have.
But it basically means that doctors 'should' approach such issues from all three sides; biological (chemical imbalance in the brain, such as a thydoid disfunction or even a Vitamin D deficiency), psychological (how someone has just 'learnt', just look at classical conditioning and such like) or social (are you having social problems at home, or lacking a social life).