I had read Phil Katz's story before and I read it again today - it wasn't any less painful the second time around. I think if we were to debug it - there doesn't seem to be any one unmistakable conclusion, rather a combination. It would all depend on how severely one reacts to their emotional trauma. Some people are numbed, some are able to move on, some find healthy diversions in hobbies, people, achievements and some like Phil just plain fail to function well and have to resort to drugs and alcohol in order to run away from the living nightmare. I think at some point existence becomes rather more painful than death for some - that's the only way you're able to kill yourself without regard.
Humans are puzzling as a species - all the years of conditioning, the everyday conflicts and contradictions we have to face, the constant need for asserting our existence through external means, the need for relations, the child/parent and then spouse systems and all the things that can go wrong with them, all the other uncertainties - amazingly many live through this but some just can't escape the dread.