Ego disturbances in the sense of Kurt Schneider: historical and phenomenological aspects.

The phenomena which were grouped together by Kurt Schneider to constitute the ego disturbances have always been of particular diagnostic relevance for schizophrenia. The manner in which these symptoms are described and distinguished from other psychopathological symptoms has generally been rather imprecise. The introduction of phenomenological methods into the field of psychiatry led to considerable improvements in symptom descriptions and to a clearer distinction between psychotic and nonpsychotic experience. Continued developments in phenomenology have further incorporated aspects of schizophrenic symptom development and in doing so have brought so-called transitional phenomena and the core schizophrenic syndrome into focus. The ego disturbances accordingly appear to stem from a particular form of depersonalization which is described as a modified sense of mineness and which can be distinguished from the neurotic experience of depersonalization.