I just happened to be reading PC blog on depression, and stumbled into this article by Dr John that concisely discusses the exact depression/diabetes analogy in point 2 below as well as other points made in the related chemical imbalance thread:

7 Myths of Depression | World of Psychology

So I thought I'd pass it on here.

PS, comma error:
>In fact, a lot of research suggests that most people can be treated for depression successfully in as little as 24 weeks with a combination of psychotherapy, and if needed, medications.

Middle comma should be after "and," rather than before it. Take out what's between the 2 last commas and the sentence looks broken.

PPS English teacher or copyeditor for hire. Meep-meep