Quick thought: In the same way that people repress their sexual urges (they don't rape everyone they want to fuck but won't be able to) is it possible that if depression was socially unacceptable we would see a lot less of it? Would people not give in to the urge to be depressed? Just now I felt a wave of depression looming and rather than give in I fought it and in doing do, I actually diminished the feeling. Had I given in to it, I would right now be in the clutches of it. I am not sure that this is the case but I suspect that there are a lot of depressed or "bipolar" (everyone under 24 is bipolar now) people who are mostly just giving into self pity and the urge to be coddled. If the culture was not so 'understanding' I doubt there'd be as many of these people.
Or they'd just repress it and live in quiet misery, I dunno.