Schizotypal personality questionnaire: new sources of validity evidence in college students

Schizotypal traits represent the behavioral expression of vulnerability to psychosis in general population. Among the most widely used measurement instruments, we could find the Schizotypal Personality Questionnaire (SPQ) (Raine, 1991). However, some aspects of its psychometric quality have yet to be analyzed. The main goal of the present study was to gather new sources of validity evidence of the SPQ scores in non-clinical young adults. The final sample was made up of 1123 college students (M=20.3 years; S.D.=2.6). The study of the internal structure using exploratory factor analysis revealed that SPQ items were grouped in a theoretical structure of seven second-order factors. Confirmatory factor analyses showed that the four-factor model (Paranoid) displayed better goodness-of-fit indices than the other hypothetical dimensional models tested. More complex measurement models, such as those tested using second-order confirmatory factor analyses and Exploratory Structural Equation Modeling, also showed adequate goodness-of-fit indices. The reliability of the SPQ scores ranged from 0.80 to 0.91. A total of 11 items showed differential functioning by gender. Advances in psychosis phenotype measurement open up new horizons to understand the structure and content of schizotypy.