I have had hallucinations from as early as I can remember, and a psychologist once told me it was because of ptsd. I had a kidney disease when I was very young and would get really sick, in and out of hospitals, high fevers to the point of convulsions. When I would get the high fevers, I would hallucinate, typical hallucinations associated with fevers (objects morfing), but I would always also have the same hallucination about people with no faces, just white, and I was really small in size, in a room that was really large, feeling alone and scared. The doctor said it was ptsd, and I still get those hallucinations when I am really tired or scared. I hate them, and at one point I thought I was going crazy...depending on my stress..these dreams or hallucination can last for a long time, they are really scary and I usually will have to keep the lights on or blink my eyes a lot.