Someone I used to have in a support group I once helped run for sexually victimized and abused young men shared with us what happened to him.
I'm not going into the finer details of it but the broadstroke is he was being victimized by a TA. He went to other teachers, school admins, and even police. No one believed him and he even got punished for "making it up to get a staff member in trouble".
It destroyed his personality. He became bitter, resentful, spiteful, and generally hateful of other people. He was improving his demeanor in the group but from what he tells us he just "wanted to watch the world die" at the time.
A couple years later that same TA tripped down the stair well in one of the side hallways of the school and he happened to be nearby. He saw she was badly injured and likely had broken bones and was bleeding from her head. Instead of helping her he literally stepped over her and pretended she wasn't there. Security footage showed he wasn't the one to push her but when asked why he didn't say anything or get help he simply said that last time he tried to tell people about something involving her no one helped so why would they this time?