Die nosologische Stellung der schizoaffektiven Störungen (ICD-10: F25): Symptomatik und Verlauf

Abstract

Kraepelin's dichotomous classification of functional psychoses with schizophrenia on the one hand and affective on the other hand was challenged by nosological concepts such as schizoaffective psychoses. This term was introduced by Kasanin when he described patients with a mixture of psychotic and affective symptoms who showed a full recovery after a few months. The modern diagnostic systems ICD-10 and DSM-IV do not follow Kraepelin's dichotomous classification but include further diagnostic categories like schizoaffective disorders. Diagnostic criteria for ICD-10 schizoaffective require the presence of both prominent affective symptoms and typical schizophrenic symptoms like thought insertion, thought broadcasting, thought withdrawal, hallucinatory voices, delusional perception or delusions of control. Concerning the regional frequency of this diagnosis, empirical investigations show a high variability. The frequency of ICD-10 schizoaffective within the whole diagnostic group schizotypal and delusional disorders ranges between 7.8 and 33.3%. Until now, the interrater reliability for schizoaffective according to ICD-10 criteria is not sufficient. Kappa-values range between 0.24 and 0.63. In particular, the nosological state of schizoaffective is still unclear. It is possible to distinguish at least four different nosological concepts (variant of schizophrenia, variant of affective intermediate entity between schizophrenia and affective continuous spectrum model of functional psychoses). Several investigations using multivariate statistical analyses failed to identify schizoaffective as a distinct entity with regard to the cross-sectional clinical picture. These findings are in line with the continuous spectrum model. Concerning the course of illness, divergent results were reported in different investigations. The course of schizoaffective seems to depend on the underlying diagnostic criteria. A temporal dissociation of psychotic and affective symptoms, the constituent diagnostic criteria for schizoaffective according to DSM-IV criteria, seems to predict a more unfavourable course. However, schizoaffective according to ICD-10 criteria are more similar to affective than to schizophrenia, compatible with the conception of a variant of affective disorders. These results support Kraepelin's dichotomous classification of functional psychoses, provided that schizoaffective are subsumed under affective disorders. Because of the more favourable course of illness ICD-10 schizoaffective should be classified not as a subcategory of schizotypal and delusional disorders, but as a subcategory of affective disorders.