I don't know how or why but I read from a credible source that high temperature (fever) causes hallucinations in people and a friend of mine's kid kept having terrible nightmares, she kept waking up screaming and was so bad that she was scared to go to sleep, slept with some religious medal to "protect" her. But during the day she was always warm, went around in a T-shirt in all weather but when she went to bed she would wear socks tucked into pjs and had a duvet and blanket over the top. So they cooled her down at night and it helped. It didn't totally stop it but I think she was so anxious a