Stratégies de résolution de problèmes et attention sélective dans la schizophrénie : critères typologiques et multidimensionnels de la Positive and Negative Syndrome Scale (PANSS)

Abstract

Introduction The Positive and Negative Syndrome Scale (PANSS) is one of the most widespread diagnostic scales of psychoses, in particular for Schizophrenia. The scale distinguishes between positive and negative subtypes. A consequent number of researches explored the cognitive dysfunction in schizophrenia by distinguishing these negative and positive subtypes. However, findings are inconsistent. On the other hand, multidimensional diagnostic criteria show the specificity of cognitive disorders within the different spheres of schizophrenia. Literature findings Studies show that principal components analyze applied to PANSS's 30 items attain from three to nine components. Therefore, psychotic, negative and disorganized dimensions were regularly obtained. Every one of these dimensions has specific neuropsychological and cognitive correlations. Objectives Our purpose was to explore cognitive disorders related to the negative and positive subtypes as defined by typological criteria and negative, disorganised and psychotic dimensions defined by multidimensional criteria. Our particular interest was selective attention and problem-solving abilities. Materials and methods Our sample incorporated 42 subjects responding to D.S.M.-IV criteria for schizophrenia (APA, 1994). The mean age was 40.58 ± 7.95 years, the mean years of education were 9.88 ± 2.74, the mean duration of illness was 12.26 ± 6.49 years and the number of hospitalisations was 4.41 ± 2.27. Clinical assessment was reached by using the Positive and Negative Symptoms Scale (PANSS). In order to define schizophrenic dimensions, the principal components analysis was performed with Varimax rotation. To assess problem-solving and selective attention, subjects were asked to complete the Wisconsin Card Sorting Test, the Parlor Game, the Stroop test and the Word Recognition Scale (ADAS-cog). Statistical significance was based on non-parametric measures: the Kruskal-Wallis test and the Spearman correlation test. Results Typological diagnostic criteria based on PANNS show no cognitive differences between positive, negative and mixed sub-types in selective attention and problem-solving ability. On the other hand, the principal component analysis applied to PANSS shows three components ; negative, psychotic and disorganisation. Clinical assessment: the negative component included blunted affect, lack of spontaneity and active social avoidance, the psychotic component included delusions, hallucinatory behaviour, grandiosity, suspiciousness and unusual thought content, and finally the disorganisation component comprised conceptual disorganisation, difficulty in abstract thinking, disorientation and poor attention. Cognitive assessment: the disorganisation dimension was associated with low performances in the Stroop test and in the Word Recognition Scale. Negative dimensions were correlated to low performances in the indicators of the Wisconsin Card Sorting Test (number of errors, number of perseverant errors, number of failures to maintain the set, number of trials to achieve the task and number of achieved categories) and the Parlor Game. However, no significant correlation was found between psychotic dimensions and cognitive dysfunctions. Conclusion Our study contributes to the comprehension of specific patterns of cognitive disorders of schizophrenics by using multidimensional criteria. Results are detailed and discussed.