Relationship of Screen-Based Symptoms for Mild Traumatic Brain Injury and Mental Health Problems in Iraq and Afghanistan Veterans: Distinct or Overlapping Symptoms?

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INTRODUCTION

Traumatic brain injury (TBI) has received greater public attention because of the conflicts in Iraq and Afghanistan (Operation Iraqi Freedom [OIF]/Operation Enduring Freedom [OEF]) [1]. An estimated 22 percent of servicemembers returning from OIF have reported experiencing TBIs and concussions [2], and of injured OIF/OEF servicemembers, 31 percent have been diagnosed with a TBI [3]. Although TBIs range in severity, mild TBI comprises roughly 77 percent of all head injuries among OIF/OEF veterans and is most challenging to diagnose because of symptom overlap with mental health disorders: posttraumatic stress disorder (PTSD) and depression, in particular [4-5].

In an attempt to increase early detection of mild TBI in returning combat veterans entering the Department of Veterans Affairs (VA) system, the VA implemented the first-level TBI screen in April 2007 [6]. The VA considers OIF/OEF veterans to be at risk for having had a possible mild TBI if, on the first-level VA TBI screen, they report a head injury with loss of consciousness or altered mental status and postconcussive symptoms (PCSs, immediately following the exposure and within 1 wk prior to screening) [7]. This definition is sensitive and identifies at-risk OIF/OEF veterans but is not necessarily specific for a TBI diagnosis because mental health conditions, such as PTSD and depression, have also led to positive responses on the VA TBI screen [8]. OIF/OEF veterans who screen positive on the VA first-level TBI screen are therefore referred for second-level TBI screening to conduct a more in-depth assessment for a history of a TBI exposure.

Given that TBI results from exposure to a traumatic event, such as a blast, symptoms of TBI commonly co-occur with both PTSD and depression [9]. TBI can increase the risk of developing PTSD and other mental health conditions because the event associated with the head injury was potentially life-threatening and was associated with other traumatic war zone exposures [10-11]. In recent studies among OIF/OEF veterans with mild TBI, an estimated 33 to 44 percent also met criteria for PTSD and 33 to 62 percent also met criteria for depression [12-14].

Particularly challenging is the fact that many of the cardinal features of mild TBI, such as memory problems, diminished attention and concentration, irritability, and insomnia, are also hallmark symptoms of PTSD and depression [10,12]. Schneiderman et al. found that PTSD was one of the factors most strongly associated with TBI-related PCSs [15]. Indeed, in one published study of OIF servicemembers with mild TBI, after controlling for the effects of PTSD, headaches were the only distinguishing feature associated with loss of consciousness in the battlefield [12]. Nevertheless, a gap exists in identifying other symptoms that differentiate TBI, PTSD, and depression.

The purpose of this study was to address this gap by identifying distinguishing features of each disorder in order to more accurately discriminate between screen-based symptoms of TBI, PTSD, and depression in OIF/ OEF veterans. Because the symptoms of TBI, PTSD, and depression can overlap clinically, problems with triage and appropriate referral for specialty care can ensue, creating delays in diagnosis and treatment [15-17]. Specifically, using factor analytic techniques, we sought to identify symptoms from TBI, PTSD, and depression screens that were overlapping and, in contrast, symptoms that were uniquely associated with a positive TBI screen (and not better accounted for by PTSD or depression). We focused on VA screen results because they represent the level of information that clinicians use to make initial decisions about diagnosis and treatment of their patients. To our knowledge, no study to date has used the VA post-deployment mental health and TBI screens to evaluate symptom discrimination in OIF/OEF veterans. A better understanding of the symptoms that differentiate among TBI, PTSD, and depression in the initial screening stage may facilitate triage, more accurate diagnosis, and early symptom management of OIF/OEF veterans. …