A friend of mine who I'll call "David" was bullied by another teacher in his department for many years. Although David was highly qualified and had a great rapport with his students, this other staff member continually made negative comments about him behind his back and ridiculed anything he did.
At first David tried to shrug this off, even when students began telling him that she was calling him an idiot in her class. She also began using David's title ("Head Teacher") at open days and when introducing herself.
After some years, David finally complained to the head of the department, but he was completely dismissive. So David began to keep a diary to show that he was the target of this teacher's negative campaign.
He saw a counsellor, who was shocked at what the diary revealed and encouraged David to take the issue to the school CEO. The CEO listened carefully and began an investigation (things were looking up at last!), but as the issue grew larger than he could reasonably handle, he ended up telling David to simply "take it like a man."
David had a type of mini breakdown, to the point where he says he can not recall a five hour period from that day, although he can remember the uncontrollable sobbing with the counsellor for an hour and a half.
He still works there, as does his tormentor.