Traumatic Brain Injury-1
Apolipoprotein E (APOE) e4 Genotype is Associated with Increased Psychiatric Distress in Veterans with a History of Mild-to-Moderate Traumatic Brian Injury

Extract

Objective: Since few studies have examined the relationship between the APOE gene and long-term clinical outcomes following traumatic brain injury (TBI), we aimed to determine whether the e4 allele of the APOE gene influences neuropsychiatric symptoms in military Veterans with a history of mild-to-moderate TBI. Method: Participants included 140 Veterans (TBI = 83, military controls [MC] = 57) who underwent APOE genotyping (participants were blinded to APOE status) and were divided into e4+ (TBI = 19, MC = 16) and e4− (TBI = 64, MC = 41) groups. All participants underwent a comprehensive neuropsychological assessment, including completion of self-report measures assessing psychological distress. The primary outcome measures were the total score from the Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), and PTSD Checklist (PCL). Two-way analyses of variance were conducted to examine the effect of group (TBI vs. MC) and e4 status (e4+ vs. e4−) across symptom measures. Results: There was a significant main effect of group across all symptom measures (TBI > MC; all p-values < .001; np² = .226–.295), no main effect of e4 genotype (p = .173–.213, np² = .011–.014), and a significant interaction of group by e4 genotype across all measures (p = .030–.041, np2 = .030–.034). Specifically, for TBI participants, e4+ Veterans had significantly higher symptom scores than e4− Veterans (p = .008–.012, np² = .046–.050). For MC participants, e4 status had no effect (p = .541–.621, np² = .002–.003). Conclusion: The results suggest a potentially meaningful relationship between APOE genotype and psychiatric distress following TBI, wherein the presence of an e4 allele conveys risk for increased symptomatology in the presence of neurological insult. Although findings are preliminary, this study furthers our understanding of how genetic factors influence response to TBI.