Psychometric properties of the Chinese version of the Posttraumatic Cognitions Inventory (PTCI) in male first responders

This study aimed to conduct the first psychometric evaluation of both the full 33-item and short-form nine-item versions of the Posttraumatic Cognitions Inventory (PTCI and PTCI-9, respectively) in a sample of first responders from China. A total of 1,448 male first responders completed the PTCI, Life Events Checklist for DSM-5 (LEC-5), and PTSD Checklist for DSM-5 (PCL-5). Confirmatory factor analysis (CFA), measurement invariance, internal consistency, and criterion validity were used to examine the validity and reliability of the PTCI and PTCI-9. Optimal cutoff scores were determined via receiver operating characteristic (ROC) curve analysis. CFA results indicated inadequate fit for the original three-factor and alternative four-factor models of the PTCI, whereas the PTCI-9 demonstrated good model fit, root mean square error of approximation (RMSEA) = .052, confirmatory fit index (CFI) = .96, Tucker-Lewis index (TLI) = .93, goodness of fit index (GFI) = .98. The PTCI-9 showed measurement invariance across subgroups with and without interpersonal trauma exposure. Both versions of the measure were significantly related to PCL-5 scores, with no difference in correlation strength. Both versions showed good internal consistency, PTCI: ω = .98, PTCI-9: ω = .90. ROC analyses suggested optimal cutoff scores of 53 for the PTCI and 16 for the PTCI-9. These results indicate that the PTCI-9 demonstrates comparable or superior psychometric properties to the full PTCI among first responders, showing greater practical utility due to its brevity.