ICD-11 posttraumatic stress disorder, complex PTSD and adjustment disorder: the importance of stressors and traumatic life events.

Although ICD-11 adjustment (AjD), posttraumatic stress (PTSD) and complex posttraumatic stress (CPTSD) are commonly diagnosed disorders following exposure to stressful or traumatic life events, their dimensional structure and co-occurrence has never been tested in a single study. The present study explored the latent structure of AjD, PTSD, and CPTSD symptoms and their relationship to stressful and traumatic life events to determine the degree of distinctiveness between these constructs. Participants were clinical patients (= 331) who completed self-report measures of stressful and traumatic life events, AjD (The Adjustment Disorder - New Module 8 (ADNM-8)) and PTSD / CPTSD (The International Trauma Questionnaire - ITQ). Using confirmatory factor analysis, a second-order model comprised of correlated latent variables of AjD, PTSD, and CPTSD provided the best fit of the data. It was also found that stressors and traumatic life events were positively associated with all of these conditions although childhood trauma was only associated with CPTSD. The current findings support the ICD-11 model of related-but-distinct stress-related disorders. We discuss the existence of a stress-response continuum and how the current findings impact the development of clinical interventions that may be shared across, or unique to, each stress-related disorder.