Suicidal thoughts are not an isolated category of thoughts or some special case, they emerge and relay in the same way as every other thought.
Quiet quitting is a term for working strictly within a job description, doing nothing extra.
Thoughts that just don't go away are familiar experiences, but what makes them so?
An aspect of mental health is determined by expectations.
There was a recent paper in Nature, Neurotensin orchestrates valence assignment in the amygdala, submitting that a neuropeptide, neurotensin determines what becomes of a memory — good or bad.