Psychometric validation of the Turkish Illness Identity Questionnaire (IIQ-TR).

Abstract

This study aimed to validate and adapt the Turkish version of the Illness Identity Questionnaire (IIQ) for cultural use. The IIQ was developed by Oris et al. to assess the integration of illness into identity. This psychometric validation investigation used a sample of young adults with chronic illness (n = 166) to evaluate a questionnaire. The questionnaire underwent forward and back translation procedures, and content and language validity was approved by experts. Confirmatory factor analysis supported a four-factor structure (engulfment, rejection, acceptance and enrichment) and demonstrated good model fit (<i>χ²/df</i> = 1.963, RMSEA = 0.076, GFI = 0.940 and CFI = 0.934). Convergent validity analyses revealed significant relationships between dimensions of illness identity, depression and life satisfaction. Engulfment, rejection and acceptance were positively related to depression and negatively related to life satisfaction, while enrichment exhibited the opposite pattern. Reliability analyses showed internal consistency ranging from acceptable to excellent, with Cronbach's alpha coefficients ranging from 0.719 to 0.907. Item-total correlations (0.380-0.799, <i>p</i> < 0.01) confirmed homogeneity in measuring illness identity. The Turkish version of the IIQ demonstrated acceptable psychometric properties, thus supporting its use as a reliable and valid tool for assessing illness identity.