Yes, I have a point system in place for several psychological mechanisms. When they fall below a certain threshold, she starts losing touch with reality. Perhaps it could even get to the point where she becomes possessed by these beings, blurring the line between whether they're real or not, or perhaps her strong belief in them actually causes them to materialise. But of course, the game is told from the perspective of an unreliable narrator, which gives me plenty of room to play around with these concepts.