Development and validation of an indigenous Urdu measure for Schizoid personality disorder in adults

Objective: To develop and validate an indigenous Urdu scale for assessing Schizoid personality disorder in adults and to evaluate its psychometric properties. Methods: This cross-sectional study, conducted between February and June 2019, utilized Diagnostic and Statistical Manual of Mental Disorders-5 criteria, existing literature, and clinical observations to develop a 63-item pool. After expert review and pilot testing, a 43-item scale was administered to 234 participants (123 males, 111 females) aged 18 to 60 years, drawn from both clinical and non-clinical populations in Gujrat, Pakistan. The scale underwent exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) to refine the items, resulting in a 14-item measure with three subscales: solitariness, emotional coldness, and indifference to praise. The psychometric properties, including reliability and convergent validity, were assessed using Cronbach's alpha and the University of California, Los Angeles (UCLA) Loneliness Scale (Version 3). Results: The Indigenous Schizoid Personality Disorder Scale (SPDS) exhibited robust psychometric properties. EFA identified four factors, with three confirmed through CFA. The scale demonstrated excellent model fit indices (CMIN/DF=1.765, CFI=0.955, RMSEA=0.057). Cronbach's alpha for the total scale was 0.887, with subscale reliabilities ranging from 0.768 to 0.852. Convergent validity was supported by a significant positive correlation (r=0.452, p<0.01) with the UCLA Loneliness Scale. Conclusion: The 14-item Indigenous SPDS demonstrated strong psychometric properties, providing a culturally relevant and reliable tool for assessing schizoid personality disorder in Urdu-speaking populations. This scale holds significant value for researchers, clinical psychologists, students, and mental health practitioners, enhancing its utility across diverse clinical and non-clinical settings.