Bifactor structure of the schizotypal personality questionnaire (SPQ). Issue 3 (30th December 2015)

• Record Type: Journal Article
• Authors: Preti, Antonio; Siddi, Sara; Vellante, Marcello; Scanu, Rosanna; Muratore, Tamara; Gabrielli, Mersia; Tronci, Debora; Masala, Carmelo; Petretto, Donatella Rita
• Is Part Of: Psychiatry research. Voume 230:Issue 3(2015)
• Page Start: 940
• Page End: 950
• Publication Date: 2015-12-30
• Subjects: Schizotypal Personality Questionnaire -- Confirmatory factor analysis -- Early Intervention -- Schizotypy -- Psychosis -- Schizophrenia; Psychiatry -- Periodicals; Psychiatry -- periodicals; Psychiatrie -- Périodiques; 616.89
• DOI: 10.1016/j.psychres.2015.11.010
• Languages: English
• ISSNs: 0165-1781

Abstract

Abstract: The schizotypal personality questionnaire (SPQ) is used to characterize schizotypy, a complex construct helpful for the investigation of schizophrenia-related psychopathology and putative endophenotypes. The SPQ factor structure at item level has been rarely replicated and no study had tested a bifactor model of the SPQ so far. The unidimensional, the correlated, the second-order and the bifactor models of the SPQ were tested to evaluate whether the items converge into a major single factor defining the schizotypy-proneness of the participants, to be used for grouping purpose. Parallel principal component analysis (PCA) and confirmatory factor analysis (CFA) were used to determine the optimal number of factors and components in a cross-sectional, survey design involving 649 college students (males: 47%). The first-order, nine-subscale model was confirmed by CFA in the whole sample. The best evidence from parallel PCA in the training set was in favor of a two-factor model; the bifactor implementation of this model showed good fit in the subsequent CFA. Two main dimensions of positive and negative symptoms underlie schizotypy in non-clinical samples, entailing specific risk of psychosis. On a measurement level, the study provided support for the use of the total scores of the SPQ to characterize schizotypy. Highlights: We tested the bifactor structure of the schizotypal personality questionnaire. We evaluated alternative models in two independent samples. Parallel principal component analysis suggested a two-factor model. Confirmatory factor analysis confirmed the bifactor implementation of this model. The study provided support for the use of the total scores of the SPQ.