Psychometric evaluation of the SPQ-Youth with Hawaiʻi school children

Abstract

Currently, there are few measures for Diagnostic and Statistical Manual of Mental Disorders (DSM) defined schizotypal personality disorder (SPD) in youth. This study describes the development and psychometric evaluation of a new measure (SPQ-Youth; Maeda, 2010) designed for this purpose. The generation of questionnaire items involved multiple methods in order to increase measurement quality, including a thorough review of the literature and interviews with mental health providers. A panel of experts in schizophrenia-spectrum disorders and child development evaluated each item for developmental appropriateness and the degree to which items measure schizotypal traits in youth. In order to evaluate the measure's psychometric properties, the SPQ-Youth and the Atypicality scale of the BASC2 (Reynolds & Kamphaus, 2004), a "measure of common markers for more serious psychotic tendencies" were administered to a large sample of students (N = 665, 42.1% male) attending various public schools on O'ahu. Exploratory factor analysis of all participant data revealed a three-factor solution, which is highly similar to that of the adult version of the measure. Findings also indicate high concurrent validity (r = .73), and internal consistency. Differences in SPQ-Youth scores were evaluated based on key demographic variables. Analyses revealed a signficant effect of age on SPQ-Youth scores (F = 5.84, p <.05), with younger participants scoring higher than older participants. In order to account for this difference, participants were split into two groups based on the median age of the entire sample. Secondary exploratory factor analyses and adjusted high and low cut-off scores were then computed for each group in order to improve the interpretive value of SPQ-Youth scores. Consistent with previous studies, secondary analyses suggests differences in item interpretation and endorsement depending on participant age. Collectively, the findings suggests that the SPQ-Youth may be a useful screening tool for youth in the general population and a supplemental diagnostic instrument in clinical or school settings. Additional studies that may help to further evaluate the measure's validity and reliability, as well as to help identify the correlates of SPD in youth are discussed.