Development and validation of an Urdu-language Schizotypal personality disorder scale: a psychometric analysis

Objective: To construct a valid measure of Schizotypal Personality Disorder Scale (STPDS) in Urdu language. Methods: The cross-sectional analytic study, approved by Departmental Research Review Committee, University of Gujrat, was conducted from February to June 2019. In the initial phase, a 27-item STPDS was developed using standardized procedures, including exploratory and confirmatory factor analysis, from an initial pool of 80 items. Data were collected from 234 participants (males=123, females=111), aged ≥18 years, recruited through purposive sampling from clinical and non-clinical populations across educational institutes, hospitals, and communities in Gujrat, Pakistan. Participants provided informed consent and completed demographic forms and questionnaires. Ethical considerations, including voluntary participation, anonymity, and confidentiality, were maintained throughout the study. Results: The Kaiser-Meyer-Olkin value was .929, and Bartlett’s test of sphericity was significant (p<.001), confirming sampling adequacy. Exploratory factor analysis identified 7 factors explaining 66.11% of the variance, with factor loadings ranging from .40 to .78. Confirmatory factor analysis yielded a good model fit (CMIN/DF=1.876; GFI=.855; CFI=.908; RMSEA=.061). A 27-item scale was finalized, demonstrating strong psychometric properties. Cronbach’s alpha for the STPDS was .941, indicating excellent reliability, while subscales ranged from .688 to .892. Convergent validity analysis with the Schizotypal Personality Questionnaire-Brief (SPQ-B) showed a moderate positive correlation (r=.454, p<.01). Conclusion: The 27-item STPDS exhibited strong psychometric properties, including reliability and construct validity, and serves as a robust tool for assessing schizotypal personality disorder. The scale is suitable for use in clinical and non-clinical settings and may aid future research and diagnosis in this domain.