Cortical thickness reduction in combat exposed U.S. veterans with and without PTSD.

We investigated the extent of cortical thinning in U.S. Veterans exposed to combat who varied in the severity of their posttraumatic stress disorder (PTSD) symptoms. In addition, we explored the neural correlates of PTSD symptom dimensions and the interactive effects of combat exposure and PTSD upon cortical thickness. Sixty-nine combat exposed Veterans completed high-resolution magnetic resonance imaging (MRI) scans to estimate cortical thickness. The Clinician Administered PTSD Scale (CAPS) and Combat Exposure Scale (CES) assessments were completed to measure current PTSD and historical combat severity, respectively. PTSD symptom dimensions (numbing, avoidance, reexperiencing, anxious arousal, and dysphoric arousal) were studied. Vertex-wise whole cerebrum analyses were conducted. We found widespread negative correlations between CAPS severity and cortical thickness, particularly within the prefrontal cortex. This prefrontal correlation remained significant after controlling for depression severity, medication status, and other potential confounds. PTSD dimensions, except anxious arousal, negatively correlated with cortical thickness in various unique brain regions. CES negatively correlated with cortical thickness in the left lateral prefrontal, regardless of PTSD diagnosis. A significant interaction between CES and PTSD diagnosis was found, such that CES negatively correlated with cortical thickness in the non-PTSD, but not in the PTSD, participants. The results underscore the severity of cortical thinning in U.S. Veterans suffering from high level of PTSD symptoms, as well as in Veterans with no PTSD diagnosis but severe combat exposure. The latter finding raises considerable concerns about a concealed injury potentially related to combat exposure in the post-9/11 era.

Neuropsychological Functioning in Veterans with Posttraumatic Stress Disorder: Associations with Performance Validity, Comorbidities, and Functional Outcomes.

OBJECTIVES: Numerous studies have shown that individuals with posttraumatic stress disorder (PTSD) display reduced performances on neuropsychological tests, although most prior research has not adequately accounted for comorbidities or performance validity concerns that are common in this population and could partially account for the observed neurocognitive findings. Moreover, few studies have examined the functional implications of neuropsychological results in PTSD. METHODS: We examined neuropsychological functioning in 44 veterans with PTSD and 40 veteran trauma comparison (TC) participants with combat exposure and no PTSD. RESULTS: After excluding four veterans with PTSD for performance validity concerns, multivariate analyses of variance by neurocognitive domain revealed significantly worse performance by the PTSD group in the domains of speed of information processing (p=.035) and executive functions (p=.017), but no group differences in attention/working memory, verbal/language functioning, visuoconstruction, or episodic memory. Group differences by PTSD status were still present after covarying for depression, a history of head injuries, and substance use disorders. Executive functioning performance was associated with poorer self-reported occupational functioning and physical health-related quality of life, while speed of information processing performance was associated with poorer physical health-related quality of life. DISCUSSION: These results are generally consistent with a fronto-limbic conceptualization of PTSD-associated neuropsychological dysfunction and show that cognitive functioning may be associated with critical functional outcomes. Taken together, results suggest that consideration of neurocognitive functioning may enhance the clinical management of individuals with PTSD.