Prevalence, assessment, and treatment of mild traumatic brain injury and posttraumatic stress disorder: a systematic review of the evidence.

BACKGROUND Iraq and Afghanistan war veterans are returning from combat having sustained traumatic brain injury, mostcommonly mild traumatic brain injury (mTBI), and experiencing posttraumatic stress disorder (PTSD). Clinical guidelines for mTBI and PTSDdo not focus on the co-occurrence of these conditions (mTBI/PTSD). A synthesis of the evidence on prevalence, diagnostic accuracy, andtreatment effectiveness for mTBI/PTSD would be of use to clinicians, researchers, and policymakers. METHODS We conducteda systematic review of studies identified through PubMed, PsycINFO, REHABDATA, Cochrane Library, pearling, and expert recommendations. Peer-reviewed English language studies published between 1980 and June, 2009 were included if they reported frequencies of traumatic braininjury and PTSD, or diagnostic accuracy or treatment effectiveness specific to mTBI/PTSD. RESULTS Thirty-four studies metinclusion criteria. None evaluated diagnostic accuracy or treatment effectiveness. Studies varied considerably in design. Frequency ofmTBI/PTSD ranged from 0% to 89%. However, in 3 large studies evaluating Iraq and Afghanistan war veterans, frequencies ofprobable mTBI/PTSD were from 5% to 7%; among those with probable mTBI, frequencies of probable PTSD were from 33% to 39%. DISCUSSION The wide range of mTBI/PTSD frequency levels was likely due to variation across studyparameters, including aims and assessment methods. Studies using consistent, validated methods to define and measure mTBI history andPTSD are needed.