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ICD-11 Versus DSM-5 Conceptualizations of Posttraumatic Psychopathology: Implications for Prevalence, Comorbidity, and Measurement of PTSD and Complex PTSD




Camden, Abigail

Type of Degree

Master's Thesis


Psychological Sciences

Restriction Status


Restriction Type

Auburn University Users

Date Available



ICD-11 and DSM-5 represent disparate approaches to diagnostic categories and criteria for posttraumatic psychopathology. First, DSM-5 follows a broad approach to posttraumatic stress disorder (PTSD) symptom criteria, whereas ICD-11 follows a narrow approach. Second, ICD-11 includes a diagnostic category of complex PTSD (CPTSD), whereas DSM-5 does not. ICD-11’s narrower approach to PTSD was intended to reduce unwarranted diagnoses, heterogeneity, and comorbidity, and its inclusion of CPTSD was intended to provide diagnostic coverage for symptoms that often occur following prolonged trauma. Previous research has demonstrated that the ICD-11 PTSD criteria lower prevalence, but findings regarding comorbidity are mixed, due in part to variability across studies in measurement methodology. The present research (N Study 1 = 938, N Study 2 = 246) sought to further examine the effect of these differing diagnostic criteria on prevalence and comorbidity of PTSD and CPTSD. It also is the first known research to examine the impact of deriving an ICD-11 PTSD diagnosis from a DSM-5 measure, the PTSD Checklist for DSM-5 (PCL-5), versus a dedicated ICD-11 measure, the International Trauma Questionnaire (ITQ). Across two studies, results demonstrated a reduction in PTSD prevalence for ICD-11 compared to DSM-5 criteria. Comorbidity findings differed across studies, with ICD-11 demonstrating generally lower comorbidity than DSM-5 PTSD in Study 2, but little evidence of comorbidity differences in Study 1. ICD-11 CPTSD prevalence was similar to that of ICD-11 PTSD, and lower than that of DSM-5 PTSD, while displaying similar comorbidity to DSM-5 PTSD. Regarding the measurement aim, there was poor diagnostic agreement between ICD-11 PTSD derived from the ITQ versus the PCL-5; prevalence and comorbidity also differed between measurement methods. Taken together, the results broadly corroborate prior findings regarding the effect of ICD-11 criteria on prevalence, mirror the discrepant comorbidity literature to date, and suggest the importance of accurate ICD-11 PTSD measurement. Additional findings, such as those for CPTSD, and associated implications, such as those for measurement, are discussed.