Bifactor structure of the schizotypal personality questionnaire (SPQ)

Antonio Preti; Sara Siddi; Marcello Vellante; Rosanna Scanu; Tamara Muratore; Mersia Gabrielli; Debora Tronci; Carmelo Masala; Donatella Rita Petretto

doi:10.1016/j.psychres.2015.11.010

Bifactor structure of the schizotypal personality questionnaire (SPQ)

Psychiatry Res. 2015 Dec 30;230(3):940-50. doi: 10.1016/j.psychres.2015.11.010. Epub 2015 Nov 11.

Authors

Antonio Preti¹, Sara Siddi², Marcello Vellante³, Rosanna Scanu⁴, Tamara Muratore⁴, Mersia Gabrielli⁴, Debora Tronci⁴, Carmelo Masala⁴, Donatella Rita Petretto⁴

Affiliations

¹ Center of Liaison Psychiatry and Psychosomatics, University Hospital, University of Cagliari, Cagliari, Italy; Section on Clinical Psychology, Department of Education, Psychology, Philosophy, University of Cagliari, Cagliari, Italy; Genneruxi Medical Center, Cagliari, Italy. Electronic address: apreti@tin.it.
² Section on Clinical Psychology, Department of Education, Psychology, Philosophy, University of Cagliari, Cagliari, Italy; Unit of Research and development, Parc Sanitari Sant Joan de Déu, Sant Boi de Llobregat, Spain.
³ Center of Liaison Psychiatry and Psychosomatics, University Hospital, University of Cagliari, Cagliari, Italy.
⁴ Section on Clinical Psychology, Department of Education, Psychology, Philosophy, University of Cagliari, Cagliari, Italy.

PMID: 26607431
DOI: 10.1016/j.psychres.2015.11.010

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.

Keywords: Confirmatory factor analysis; Early Intervention; Psychosis; Schizophrenia; Schizotypal Personality Questionnaire; Schizotypy.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Cross-Sectional Studies
Endophenotypes
Factor Analysis, Statistical
Female
Humans
Male
Models, Psychological*
Personality Inventory / statistics & numerical data
Personality*
Psychometrics / statistics & numerical data
Reproducibility of Results
Schizotypal Personality Disorder / diagnosis*
Students
Surveys and Questionnaires*
Young Adult