You may find this article about jinn (http://www.economist.com/world/displaystory.cfm?story_id=8401289) to be of interest. The concept of a local belief that jinn 'whisper into the ears of suicide bombers' caught my eye. Linking of malign spirits with mental illness is featured in this review about Anglo-Saxon elves (http://www.forteantimes.com/reviews/books/549/elves_in_anglosaxon_england.html).