The Wing of Madness

I have a friend who is part of a small, informal 'alternative' Christian fellowship in London, and through them she's become involved in the case of a young girl elsewhere who, they are convinced, is the victim of multiple demonic possession. I was asked whether I could find someone with medical experience who also could appreciate the spiritual side of the matter. I did; but everyone I asked for advice confirmed my own impression, that all the symptoms described sound like classic split personality disorder, and while nobody can be sure from a distance, there would not appear to be any supernatural element in the case. Predictably, my friend's friends (who I met and spoke to on Sunday) aren't inclined to take this advice, and are carrying on talking to the 'demons' to ascertain their plans. I think this would be completely the wrong approach even if there WERE a diabolical influence at work, so I can't have anything to do with it unless they want to come back to me.
However I did learn something from the experience. It upset me very radically: that night I had a series of bad dreams, which I don't normally suffer from, and I didn't work out why until the middle of Monday. I walked along an ordinary Lamford street watching happy people going about their lives, the blossom on the trees, the bright sun on the gardens, and at once the confusion in my mind escalated until it seemed the sun was black and the landscape screaming: the same experience that produced The Scream in Edvard Munch. This was the shadow of the wing of madness, a world in which there are no rules and the rational mind can get no purchase. What I'm really afraid of is going mad.