I think psychosis might lie dormant. Extreme stress or use of street drugs such as cannabis (especially chronically), psilocybin and LSD, might trigger it. I attribute my own psychosis to the initial damage these first two common 1980s substances caused, which life experiences multiplied. None of us emerge problem free. Even the nonexistence of problems could potentially precipitate a "can't be that lucky" anxiety. Pinpointing a cause of psychotic illness is tricky. The initial culprit and the proverbial "straw that broke the camel's back," may be a few years apart.
I believe it is possible to significantly improve from severe mental illness, even to the point that you feel recovery has been achieved.
This website is not for me to tell the world I've had a bad time. It does share aspects of my life though. I think it took me ~25 years to feel like "my house was perhaps on rock and no longer on sand." And we're never sure of anything, because between now and the day we die it could all change.
When an implausible piece of good fortune happens (if we're ever that lucky) perhaps it's "God."
Initially labels are useful to offer explanations why someone's life went off track. Long-term though, our identification with labels might not help. If recovery is possible, I see detachment especially from labels, to be important.
Labels are professional conveniences. They group patients with similar symptoms who often receive similar treatments. Every case is different though, whether it is ultimately described as bipolar disorder, schizophrenia, or anything else. Label identification is group identification, and recovery should lead to individuality.
It is magic to realise our uniqueness. It might take a paradigm shift, as in St Paul's conversion on the road to Damascus, which I treat figuratively. That event changed Paul in an instant. I had a similar, but secular moment. How long does it take to embrace an idea, or make a decision? Study takes time, choice is instantaneous...
Perhaps life's main task is for us to be ourselves? Even the perceived most successful person in the world, would not know how to be anyone else other than the perceived most successful person in the world. Logically then, if you try to be your best YOU; then bingo, you've cracked it, because you're the only expert for the job. That's what everyone should be attempting, with their own peculiarities. Trying to steal another person's "job-sheet" is like trying to run an Android APP on an iPhone. It will not work.
It's a complete folly to attempt a different job. If everyone tried, and successfully became that perceived most successful person in the world, the word "most" would no longer apply. You can't have differences when we'll all identical. If we all had that status of most successful, then our efforts have made everyone commonplace, and no-one can share anything that's not already known or of value.