You're Mine {Yandere X Tsundere}

This novel is about a young lady who is put into a mental asylum. She is struggling with depression due to her friend getting killed and her being a witness.
She's also quite psychotic. She'd do anything to get something she wants.
In the hospital people approach her but she just runs away. This all changed till one day...
A guy with the same problems as her is put into the same room as her. They get to know each other.
She then starts slowly falling in love with him..
He started getting signs that it wasn't safe to be friends with her anymore.
He began to slowly avoid her.
When she starts realizing she snaps and starts loosing her sanity.