Psychometric properties of the 9-item Posttraumatic Cognitions Inventory (PTCI-9) in an Iranian sample

The Posttraumatic Cognitions Inventory (PTCI) is a widely used measure for assessing negative posttraumatic cognitions that are common among individuals with trauma-related disorders. There was a need for a valid and reliable short form of the PTCI in Persian.

This study aimed to translate the 9-item version of the PTCI (PTCI-9) into Persian and evaluate its characteristics and psychometric properties.

This was a cross-sectional psychometric study using the translation and back-translation technique. Experts assessed the scale's content validity. Participants were 207 Iranian individuals recruited from the general population, 151 of whom were trauma-exposed. Participants completed the Persian version of the PTCI-9, the Beck Depression Inventory (BDI-II), and the World Health Organization Quality of Life (WHO-QOL) scale. The psychometric properties of the Persian version of PTCI-9 were assessed using exploratory and confirmatory factor analysis (CFA) methods. Cronbach's α coefficient and Pearson's correlation coefficients were also calculated.

Factor analyses supported a three-factor model including the Self, World, and Self-Blame subscales. The Cronbach's alpha of the Persian version of PTCI-9 (α = 0.74) and its subscales (0.76, 0.82, 0.78) demonstrated acceptable reliability. The Persian PTCI-9 also had strong test-retest reliability (r = 0.79). The correlations between the Persian version of the PTCI-9 and the BDI-II (r = 0.60) and the WHO-QOL (r = -0.54) indicated that the scale also has convergent validity.

The Persian version of the PTCI-9 showed acceptable psychometric properties. It is a brief and pragmatic measure that can be used in Iranian trauma-exposed patients for research and clinical purposes.