Diagnostic comparisons of PTSD and complex PTSD in clinical adolescents: Detection rates and ACEs as risk factors

Background: Adolescence is a developmentally sensitive period for trauma-related psychopathology, yet posttraumatic stress disorder (PTSD) is defined differently across diagnostic systems. The DSM-5 conceptualises PTSD broadly, whereas the ICD-11 distinguishes PTSD from complex PTSD (CPTSD), raising questions about diagnostic alignment and clinical meaning in youth.Objective: This study examined the diagnostic concordance between DSM-5 PTSD and ICD-11 PTSD and the differentiation between DSM-5 PTSD and ICD-11 CPTSD in adolescents, further evaluating whether adverse childhood experiences (ACEs) differentially predicted diagnoses.Method: Participants included 585 adolescents aged 13-20 years from psychiatric outpatient clinics and 2146 control adolescents from schools. DSM-5 PTSD was assessed using the PTSD Checklist for DSM-5, ICD-11 PTSD and CPTSD were assessed with the International Trauma Questionnaire (ITQ), and ACEs were measured using the ACE International Questionnaire (ACE-IQ). Least absolute shrinkage and selection operator (LASSO) logistic regression and receiver operating characteristic (ROC) analyses were used to identify stable adversity-based predictors and evaluate model discrimination.Results: DSM-5 PTSD prevalence was substantially higher than ICD-11 PTSD prevalence in both samples. ACEs showed minimal predictive value for ICD-11 PTSD but strong associations with DSM-5 PTSD and ICD-11 CPTSD, particularly cumulative adversity and community violence. DSM-5 PTSD aligned more closely with ICD-11 CPTSD than with ICD-11 PTSD in adolescents, and ACEs predicted diagnostic differentiation primarily in samples with lower trauma exposure.Conclusions: By directly mapping diagnostic overlap and adversity-based differentiation within adolescent cohorts, this study addresses a critical gap in the literature regarding the age-specific validity and clinical meaning of DSM-5 and ICD-11 trauma diagnoses.