[vickytnz]

Perhaps a better way of phrasing this is: suffering from depression? Don't do that startup unless you have a safety net (of course, that could apply to people without depression too). Hell, I'd say that applies to doing a PhD (I'm in one right now) or anything that does mean you have to deal with a lot of ambiguity on your own. In those situations it's all too easy for even the most mentally secure person to start neglecting themselves in the service of the work (mentally, emotionally, psychologically, physically), potentially to disastrous effects.

[vickytnz]

Oh, and to add to my own comment, I'd also say you could swap out "depression" to "ongoing medical condition".

Similar thing, it's fine if you manage it, if you don't things could get a whole lot worse (and other people will end up hating you for either carrying your load or being let down)