A commenter here (sorry I forget who posted it) brought my attention to this wonderful sermon, by Tim Keller in 2003. I strongly encourage you to listen to it, even if you are a non-believer; there is a lot of secular wisdom here.
For example, a little before the halfway point he says that the people who contemplate (or go through with) suicide are those who either (a) realize they are never going to achieve their life’s dream or (b) actually achieve their life’s dream.
This dovetailed with half of what I had stumbled upon myself. I was trying to understand why so many rock stars, movie stars, etc. are so messed up, when any type of “rational” model of humans would make you think they should be among the happiest. I had concluded that they were rich, famous, married to a movie star, etc., and they still weren’t happy. So the recognition of that would indeed drive you to kill yourself, either in one drastic act or over a period of years through destructive behavior.
Last thing, if you are the kind of person who really needs to hear this talk, I strongly encourage you to just go to a quiet spot and listen to it. I.e. don’t play it in the background while you’re doing housework or driving to the gym, just take 45 minutes and listen to it.