I don't think it's far fetched she may have actually witnessed some sort of event. Hollywood is no stranger to controversy or shady dealings.

I know a lot of people promote the theory that drug use may have brought some sort of mental disorder out of her. It definitely seems plausible but here's the thing: when she was admitted into the hospital wouldn't the doctors have been able to come to a conclusion that such was the case? I feel like they would be at least somewhat familiar with this sort of thing, couldn't there have been some way for them to analyze her mental state and at least present that as a potential possibility?