Posttraumatic stress symptoms in Australian parents of autistic children: Factor structure of the International Trauma Questionnaire (ITQ) and the Posttraumatic Stress Disorder Checklist for the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (PCL-5).

Objective: Research indicates that parents of autistic children may have a higher risk of posttraumatic stress disorder (PTSD) than parents of neurotypical children. This study was to determine the optimal factor structure of two trauma screening assessments: the PTSD Checklist for Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5) and the International Trauma Questionnaire, within this parent population.

Method: Confirmatory factor analysis examined and compared one novel DSM-5 model and 14 previously identified DSM-5 and International Classification of Diseases 11th Revision (ICD-11) trauma symptom models among Australian parents of autistic children (N = 563).

Results: Three DSM-5 PTSD models (anhedonia, hybrid, and intrusion/distress) provided a marginal fit, with the novel intrusion/distress model offering a superior fit. None of the five DSM-5 models tested achieved a good overall fit. For ICD-11, a three-factor model best fit the latent structure of PTSD symptoms. For complex PTSD (CPTSD), a two-factor second-order model and a six-factor first-order model provided a superior fit over five alternative CPTSD models.

Conclusions: Results strongly support the internal reliability and construct validity of the ICD-11 PTSD and CPTSD models in Australian parents of autistic children, as measured by the International Trauma Questionnaire. The ICD-11 models outperformed the best DSM-5 models, highlighting their superiority for this population. While more complex DSM-5 models showed better fit than simpler ones, they still did not achieve a good overall fit. Notably, the results were largely consistent when assessing individuals meeting Criterion A for PTSD, specifically in relation to parenting-related traumatic experiences. The International Trauma Questionnaire is a more reliable and suitable tool for assessing PTSD and CPTSD in Australian parents of autistic children. (PsycInfo Database Record (c) 2025 APA, all rights reserved).