[Communicated insanity, folie a deux and shared psychotic disorder. Different concepts and a case from Mallorca]

Following an earlier description of the psychopathological conceptions of "communicated insanity" we focus on a remarkable difference concerning the development of the historical terminology. The current operationalized definition is oriented at the originally French conception of the "folie à deux" which includes an adoption of certain delusional ideas by an intimate other. Compared with that, in the German psychopathological tradition those cases were also included in the conception of the "induziertes Irresein", in which the shocking experience of another's psychosis may cause a psychotic illness of somebody else. In modern psychiatric terminology this kind of "induction" is rather disregarded. We report a case of an induced psychosis in two women and give particular attention to the German psychopathological tradition because of still existing clinical relevance.