Can you go to mental hospital because you were involved in a fight?

Im a good girl and never gotten in a fight before. One girl in my school had a fight with this other girl in my school. She got suspended and Im not sure if the other girl did too. She told me "After the fight, the teacher locked me in a room, called the police, and they soon arrived. When they came they hand-cuffed me and sent me to a mental hospital." Why would they do that? And is this actually required?