The Duphar Lecture: on the etiology of alien, nonself attributes of schizophrenic 'voices'.

The etiology of schizophrenic hallucinations of 'voices' remains unknown. The following is a discussion of a hypothesis linking these hallucinatory phenomena to a disruption in discourse planning. The relationship between normal imagery and hallucination is discussed. The concept of 'alien intentionality' is introduced, and a theoretical argument is presented which links this phenomenon with the exteriorization of internal images. Statistical data linking discourse planning disruptions and schizophrenic data are reviewed, and a description of the treatment of a hallucinating schizophrenic via a novel type of speech therapy is described.