[Theories of cognitive disorder in schizophrenia based on psychological experiments (author's transl)].

Over the last few years, psychological experiments have provided a major contribution to research in schizophrenia. Historical, practical and theoretical grounds led to investigations mainly in the field of cognitive disorder. Independent psychological theories of schizophrenia emerged from the body of experimental results, at first restricted to mental performance of the patients but later generalized to center on the total problem of schizophrenia. In accordance with psychiatric thinking, psychologists favoured cognitive deficit as the essential schizophrenic characteristic which would possibly generate the basic symptomatology. Apart from methodological considerations, the main question arising is if this feature is truly typical of schizophrenia. The problem of the different concepts of schizophrenia has to be considered in this connection. A survey of theories of schizophrenia which are sufficiently consolidated by psychological experiments reveals that two lines of theoretical reasoning exist: one based on specific cognitive disorder, and the other where this is not the case. Encompassed by the first classification are the considerations of Bannister, Rodnick and Germezy, Shakow, McReynolds, Silvermann, L.J. Chapman, Payne, Mednick, and Epstein, as well as the interference theories (with the exception of Callaway's version)..