My oral presentation topic is the Why the WWII can give so much mental harm to Jewish survivor

The World War Two is known as one of the brutalest war in human history, uncountable booming and killings has upset tens of thoussands of people. During the merciless war, the Nazi had killed millions of Jewish people, only little of them could survive, one of the characters in the novel "a Murder is Announced", Mitizi, was one of the Jewish survivors, she suffered frorm serious mental pressure, she always afraid of being traced by the Nazi, and thought that the Nazi may come back for her, I would like to find out why the WWII can bring such a big harm to Jewish survivor's mental function, I am looking for useful information and hopping to have a detailed presentation, the process is quite satisfactory so far.

USEFUL LINK: http://www.britannica.com.ez.sccd.ctc.edu:2048/EBchecked/topic/269548/Holocaust/215491/Jewish-resistance?anchor=ref717220