[Identification by typological analysis of distinct groups of schizophrenic patients. Applicability of a disorganized schizophrenia subtype].

Since Crow, Andreasen et al. have described schizophrenia in terms of negative and positive symptoms, the dichotomic approach has been well established. As a matter of fact, factor analyses, especially principal components analyses, led with symptomatic specific scales, have proved their validity. But they have shown their limits too : some authors think that the dichotomic model fails to explain all of the schizophrenic psychopathology and that a third dimension including formal thought disorders, most of the time called "disorganization", should systematically be taken into account. In this study, the authors have hypothesized that a categorial approach could describe this "disorganization". Using a cluster analysis they investigated the existence of subtypes in a population including 136 schizophrenic patients assessed with the PANSS (Positive and Negative Syndrome Scale, Kayet al., 1987). The results suggested at least five subtypes: a pure positive subtype, characterized by high scores on items delusions, hallucinatory behavior, suspiciousness/persecution, and by a low score on conceptual disorganization item; a disorganized positive subtype, characterized by high scores on positive items, including conceptual disorganization item, and also high scores on unusual thought content and autistic preoccupation items; a negative subtype, characterized by high scores on negative items and low scores on positive items, including conceptual disorganization item; a mixed subtype, characterized by high scores on the most positive, negative and general psychopathological items; a residual subtype, characterized by low scores on all the positive, negative and general psychopathological items. The good validity of this analysis was showed since differences on a number of clinical characteristics were observed between the five clusters. These results demonstrated the oversimplication of the positive-negative dichotomy and the relevance of a disorganized subtype.