[The revised definitions of schizophrenic disorders in ICD-10 and DSM-IV].

Starting from the original concept of "dementia praecox", in this article, the ICD 10 and DSM-IV revisions of their respective definitions of schizophrenia are made more transparent and evaluative in regards to their development. For the ICD 10 definition, the schizophrenia concept of K. Schneider and its characteristic orientation towards diagnostic validity had a pre-eminent impact, whereas in DSM-IV the authors intended to follow the schizophrenia concept of E. Bleuler and thereby aimed at placing greater emphasis on the negative symptomatology. However, the results of the revision of schizophrenic disorders of this diagnostic system surprisingly leaned again towards the concept of K. Schneider. With regard to own findings on the diagnostic validity of positive and negative symptoms, it is shown that this result is justified in accordance with the present state of the art in schizophrenia research. In addition, the article deals with the definitions of schizotype features, prodromal and residual symptoms in these new diagnostic systems and critically evaluates these elements. To sum up it is clear that the recent definitions are based on the German psychopathological tradition on the one hand and the empirical findings of the last centuries on the other. Taking the latter into account, this might lead to a new understanding of schizophrenic disorders in the future.