[In Jade's experience, it was a combination of both trauma and the supernatural, the latter being more recent. She can't say whether or not where the voices came from before her magic, but after... Well, at least it somewhat validated some of her deepest fears with regard to her sanity.]

It's... more complicated than that.

[She'd explained it to Dimitri and Alice, so she at least knows how to explain it in a way that might be easier for one not from her world to understand:]

To put it simply, it's my magic. Due to the nature of it, I get sick sometimes, if I don't manage it. And, well, after 114 years of not actively managing it, the negligence has taken its toll. But as long as I'm not passed the point where I'm turning into an undead, I'll be fine. Headaches and hallucinations I can handle. Having pus and boils all over my body... that's another story.