The Impact of PTSD and mTBI on the Relationship Between Subjective and Objective Cognitive Deficits in Combat-Exposed Veterans

Objective: Cognitive complaints, such as attentional or memory concerns, are commonly reported by veterans diagnosed with posttraumatic stress disorder (PTSD) or a history of mild traumatic brain injury (mTBI). The degree to which those complaints actually map onto measurable cognitive deficits is unclear and is likely complicated by the severity of trauma-related sequelae. In the present study we sought to characterize the degree to which PTSD symptoms and mTBI accounted for the relationship of subjective cognitive complaints to objective cognitive performance, with the goal of facilitating the accurate assessment of trauma-exposed veterans complaining of cognitive decline. Method: A sample of 203 U.S. military veterans previously deployed to Iraq and/or Afghanistan were assessed for PTSD severity, history of blast and impact mTBI, objective cognitive function, and subjective cognitive complaints. Separate mediation analyses were conducted to explore the degree that PTSD severity, blast mTBI severity, and impact mTBI severity influenced the association between subjective cognitive complaints and objective cognitive performance. Models reflecting significant mediation were followed by post hoc moderated mediation analyses. Results: Subjective cognitive complaints and objective cognitive performance were significantly associated (beta = -6.49, SE = 2.85, p=.03), but this relationship was mediated by PTSD severity (beta = -2.95, SE = 2.86, p=.30). PTSD mediation was not moderated by either blast or impact mTBI. Conclusion: The present results delineate the prominent impact of PTSD symptoms, relative to blast and impact mTBI, on cognition following combat. These findings highlight the importance of assessing for trauma-related psychopathology in those seeking neuropsychological assessment or rehabilitative care for cognitive complaints.