Validation of ICD-11 PTSD and complex PTSD in foster children using the International Trauma Questionnaire

Objective ICD-11 introduces post-traumatic stress disorder (PTSD) and complex PTSD (CPTSD) as two distinct trauma-related disorders. Using the International Trauma Questionnaire (ITQ) as disorder-specific measure, this study is the first to examine the factorial and construct validity of ICD-11 PTSD, CPTSD and the ITQs' applicability in children. Methods Two hundred and eight Austrian foster children completed a set of standardized measures. Excluding participants who reported not having experienced any kind of trauma, a final sample of 136 children completed the ITQ. Factorial and construct validity of ICD-11 CPTSD and psychometric properties of ITQ scales were assessed by factor analysis and latent class analysis. Results Confirmatory factor analysis supported the two-factor higher-order model of ICD-11 CPTSD in children by high factor loadings and excellent model fit. Reliability and regression analysis evidenced psychometric adequacy and discriminant validity of ITQ scales. Latent class analysis substantiated construct validity of ICD-11 CPTSD, identifying a CPTSD (22.8%), PTSD (31.6%) and low symptoms class (45.6%). The CPTSD class showed highest rates of childhood trauma, comorbid psychopathology and functional impairment. Conclusion Factorial and construct validity of ICD-11 CPTSD was evidenced in children for the first time using precise descriptions of ICD-11 symptom content, supporting the reliability and validity of the ITQ in children.