It cannot happen all at once..
im not so sure this is true. according to:
[The psychogenic death of Mr. J. A case report]
psychogenic death occurs when:
The individual finds himself in a situation where external forces have lead to a restriction of his world and, in addition, is subjectively sensing of the inalterability of his situation. Decisive to the perception of the environment is the subjective emotional view of things which can greatly diverge reality.
it seems like this process should take some time to complete, with reports ranging from anywhere between three to five days, to as long as a month.
however, according to the case of mr. j:
The patient suffered from a painful herniation of intervetebral disk. After the operation of the disk he still had backache. He thought that the operation had been unsuccessful. The following day the patient showed the symptoms of the psychogenic death and died within one day.
while this isnt technically the same as “all at once”, considering durations reported in other cases, mr. j achieved resolution relatively quickly.
one might argue this wasnt exactly an authentic case, as the definition of 'psychogenic' is: “having a psychological origin or cause rather than a physical one”, and the impetus for the case of mr. j was an overwhelming despair brought on by persistent physical pain causing him to believe a prior surgery was unsuccessful.
so basically, little column a, little column b.
also, the entire process may have technically taken longer than the article made it sound, since due to the fact we dont really have any information regarding mr. j's state of mind prior to undergoing the procedure he subsequently deemed “unsuccessful”, we have no idea when he began to sense his world had become inalterably restricted.
i just felt like it was an interesting observation as far as the answers to this post are concerned.