> First, all patients presented with nearly identical movements and vocalizations that not only resemble Jan Zimmermann’s symptoms, but are in part exactly the same, such as shouting the German words Pommes (English: potatoes), Bombe (English: bomb), Heil Hitler, Du bist häßlich (English: you are ugly) and Fliegende Haie (English: flying sharks) as well as bizarre and complex behaviours such as throwing pens at school and dishes at home, and crushing eggs in the kitchen. > Fourth, in some patients, a rapid and complete remission occurred after exclusion of the diagnosis of Tourette syndrome.

To a first approximation, the kids are 'faking it'. The third point I didn't quote was that symptoms appear when it will preclude then from doing a tedious task, and then disappear when they are doing something they want to do.