Having analyzed the main nosographies concerning the endogenous psychoses problem, the A. aim at obtaining a subdivision of the psychotic patients into classes based on the similarity shown by the same patients about symptoms found out by a transverse examination. For this purpose, 246 psychotic inpatients have been given PSE to evaluate the presence/absence of 18 symptoms considered discriminant to the clinical rating of the patients. Such data have been processed by a Cluster Analysis. We got 7 groups of probands that have stressed the relevant number of cases with a mixture of affective and schizophrenic symptoms. We suggest the use of a bidimensional model to get a proper fitting of psychotics with mixed symptomatology.