PSYCHOMETRIC EVALUATION OF A BULGARIAN VERSION OF THE NARCISSISTIC PERSONALITY INVENTORY NPI-40

Abstract

This study reports the translation, adaptation, and psychometric evaluation of a Bulgarian version of the Narcissistic Personality Inventory (NPI-40). Following independent forward and backward translations and expert review, the instrument was administered online to 664 Bulgarian adults (77.7% women; mean age, M = 38.0, SD = 11.2). Participants also completed the Regulatory Focus Questionnaire to assess the convergent validity of the results. Classical test theory indices demonstrated high internal consistency for the total NPI-40 score (α = .85; ω = .85), though two subscales (“Self-sufficiency” and “Entitlement”) yielded lower reliabilities (α < .50). Correlational analyses supported convergent validity, revealing positive associations between total and subscale NPI-40 scores and the Promotion focus, and negative associations with the Prevention focus. Confirmatory factor analyses compared correlated seven-factor, hierarchical, and bifactor models. The bifactor solution demonstrated superior fit (CFI = .988; RMSEA = .020), confirming a strong general narcissism factor alongside specific dimensions. These findings suggest that the proposed Bulgarian version of the NPI-40 is a reliable and valid measure of trait narcissism in nonclinical samples. Thеsе results facilitate the use of the NPI-40 in Bulgarian language research across various psychological domains, including personality, interpersonal relationships, leadership, and organizational behavior.