The time lines, the compromises and the urgency are all different at a startup. You are used to being the smartest guy in the room at a mid sized or big place, you go to a small startup that got money because the founders are exceptional and they've staffed up with some exceptional people and they are all running like hell, you might look or feel kind of ordinary and that's a tough pill to swallow. It's especially difficult if you've never felt it before, all the sudden you're "failing" Combine that with a family that thinks the world of you because "you're the best" and I expect it's worse. Or at least that is how I've tried to understand it. There are clearly other issues when it results in suicide though. Again, I'm no doctor, but I try to give them an interview problem they can't solve, I think it's good if they say "I don't know how" or "I can't do that yet"
Another symptom I've observed, when someone is in that space, they often try to do more. Rather than botching one feature, maybe they'll rush and half-ass three or four to try and "make up" for earlier shortcomings. That usually creates a rift with the team that then starts to think less of them, the new guy is a bull in a China shop.
As for management, they share some of it. Uber seems like a broken place in a lot of ways. They should know it takes time to ramp up. Also success begets success, I take things off a new employee's plate when this happens. Make it small enough for them to create a little success and then build on it. In SV there is a large talent pool and a belief that the "right person" is around there somewhere so building long term success might not be as important to some companies.