To say that depression is not like diabetes I think is a bit premature at this stage. Clearly both are complex, chronic conditions. In fact, there are multiple different types of diabetes, some are due to a lack of insulin, others are not. It is likely that there are multiple types of depression, some with biogenic origin, some that are not.

It's not really faith I think, but rather a learning curve.

I think it's just too early to make blanket statements. Thoughtful deliberate choices are are important.

So there's not a blood test for it. So what? There's not a blood test for pain either, but, well, the symptoms are treatable even if the underlying condition is not. Is pain caused by a deficiency in endogenous pain modulators, no, but low levels of them make pain worse.

To each his own. There is certainly nothing criminal about people's choices or how they opt to manage and survive. Most of aren't blind children being led hither and yon by some evil doctor at the mercy of the pharmaceutical industry. Most of us don't want a happy pill, but to just feel better in order to live the life we chose.

Sometime theory is important, and sometimes outcome is even more important.