[Dysthymic schizophrenia. An investigation of its evolution].

Schizo-affective psychosis raises the nosological problem of the boundaries between the schizophrenia and the affective disorders. In the french classification (I.N.S.E.R.M., 1968) there is only the group of "chronic schizophrenia with mood disorders". In the DSM III-R the schizo-affective psychosis has its own criteria for the first time. A brief historical survey reveals the vicissitudes of the evolution of this american concept. J. Kasanin first proposed this term in 1932 to differentiate from the dementia praecox a group of cases with good prognosis. For all that, the schizo-affective psychosis remained included in the schizophrenia illness until the DSMII (1968). Under the influence of factors (principally the international comparative studies of diagnosis of mental disorders) the american psychiatry reconsidered its system of classification and elaborated the Research Diagnosis Criteria (Spitzer, 1975). The first studies quickly led to an opposite position because the schizo-affective psychosis became principally a subgroup of the affective disorders (DSM III, 1980). The studies of the last ten years generally criticized this new classification. Among the schizo-affective group they tried to separate the schizophrenic cases from the affective cases by subdivisions according different axes (mainly schizophrenic vs mainly affective, manic type vs depressive type, unipolar type vs bipolar type). Today the review of these studies did not lead to resolve the nosological problem. However the studies corroborate the model that schizo-affective illness is a heterogeneous disorder with schizophrenic cases and affective cases.