Elucidating the transdiagnostic dimensional structure of trauma-related psychopathology: Findings from VA cooperative study 504 - risperidone treatment for military service related chronic post traumatic stress disorder.

Background: Three of the most common trauma-related mental disorders-posttraumatic stress disorder (PTSD), major depressive disorder (MDD), and generalized anxiety disorder (GAD)-are highly comorbid and share common transdiagnostic symptom dimensions of threat (i.e., fear) and loss (i.e., dysphoria) symptomatology. However, empirical evaluation of the dimensional structure of component aspects of these disorders is lacking.

Methods: Using structured clinical interview data from U.S. military veterans with chronic military-related PTSD, we evaluated the transdiagnostic dimensional structure of PTSD, MDD, and GAD symptoms. We then examined the relationship between the best-fitting transdiagnostic model of these symptoms, and measures of physical and mental functioning, and life satisfaction and well-being.

Results: Exploratory factor analysis revealed that a 3-factor transdiagnostic model comprised of loss (i.e., dysphoria), threat (i.e., anxious arousal, re-experiencing, and avoidance symptoms), and somatic anxiety (i.e., physiological manifestations of anxiety) symptoms provided the best representation of trauma-related PTSD, MDD, and GAD symptoms. Somatic anxiety symptoms were independently associated with physical functioning, while loss symptoms were independently associated with mental functioning and life satisfaction and well-being.

Limitations: Evaluation of study aims in a relatively homogeneous sample of veterans with chronic, military-related PTSD.

Conclusions: Results of this study suggest that a 3-factor transdiagnostic model best characterizes the dimensional structure of PTSD, MDD, and GAD symptoms in military veterans with chronic military-related PTSD. This model evidenced external validity in demonstrating differential associations with measures of physical and mental functioning, and life satisfaction and well-being. Results provide support for emerging contemporary models of psychopathology, which emphasize transdiagnostic and dimensional conceptualizations of mental disorders. Such models may have utility in understanding the functional status of trauma survivors.