I know it is intended as fiction but Hollywood liked to truth and make more sensationalized. Like the movie "The Exorcist," for example. That was based on a true case but it was about a boy not a girl. And Hollywood over sensationalized the story for dramatic effect.
I was specifically referring to this week's episode on the scene where the head nun was trying to infect the other nun's soul with bad energy.
That part I felt had some truth to it.
But all in all it is fiction.