Once you realise something is permanent and can't really be fixed during your lifetime, then I think the catalyst for misery and contemplating ctb is logical/rational rather than purely emotional. I've been suicidal since I was around 12 years old, and have tried to analyse and repair my life from all sorts of angles. At this point, I'm out of options, so the conclusion to this story seems pretty rational to me.
Sure, when I was 12 or 13 years old, it made sense to say, I'll wait it out. There must have been some sort of novel help awaiting in the future right? Something that would ease me out of all the damage done by trauma. When I found out I had autism, and then the physical health problems started compounding too, I searched for so many things to ameliorate these issues, only to find out that it was too late and the damage had already been done.
Now, I am 23 years old with no family (except a grandparent who is at the age where death is imminent), no close friends, years worth of trauma, abusive relationships, and neglect that gave me ptsd, incurable health problems like chronic fatigue, IBS that's so bad to the point where I have to use enemas, degenerative discs, have no prospects for employment because I can't work a 9-5 with my problems, autism that prevents me from forming good relationships and causes me constant sensory discomfort.. Plus I've probably have about 20 different pharmaceutical treatments under my belt for various things that have failed massively.
I have a pretty clear idea of the tools and resources someone needs to build a half decent life, and I have none of them. When I've had jobs before, or during school, and now university, I've been surrounded by people whose parents or family members laid the foundations for them to succeed. My health problems have now been around for about 6 years, they aren't going away, and unlike everyone else I don't have a family to support and look after me- no matter how disabled I become. There really is no help for adults because we are assumed to have stable childhoods that prepared us to survive in the future.
One can survive without some of their needs being met, but you can't sustain yourself when a majority of needs are being neglected consistently. The system of "help" isn't designed for this. It's made for people who had a temporary bout of depression or anxiety, got cured within a few weeks with help and support from family, friends, and institutions, and then try to speak for everyone. The system is not built for chronically suicidal people, abuse victims, those with childhood trauma, physical health problems, or mental illnesses that go beyond cookie cutter definitions.
I'm not being emotional when I say I don't have any options left but eventual ctb. I've come to this conclusion through years of trial and error, pain, and failure. To have people say this sort of affliction is temporary or impulsive is like spit in one's face, when you've tried everything to make a life and the world has denied you of that.