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EFFECT OF THE APOE ε4 ALLELE AND COMBAT EXPOSURE ON PTSD AMONG IRAQ/AFGHANISTAN‐ERA VETERANS
Author(s) -
Kimbrel Nathan A.,
Hauser Michael A.,
Garrett Melanie,
AshleyKoch Allison,
Liu Yutao,
Dennis Michelle F.,
Klein Rebecca C.,
Beckham Jean C.
Publication year - 2015
Publication title -
depression and anxiety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.634
H-Index - 129
eISSN - 1520-6394
pISSN - 1091-4269
DOI - 10.1002/da.22348
Subject(s) - psychiatry , medicine , depression (economics) , apolipoprotein e , posttraumatic stress , clinical psychology , allele , psychology , genetics , gene , disease , biology , economics , macroeconomics
Background The apolipoprotein E (APOE) ε4 allele has been implicated in a range of neuropsychiatric conditions. The present research examined if the ε4 allele of the APOE gene moderated the effect of combat exposure on posttraumatic stress disorder (PTSD) among Iraq/Afghanistan‐era veterans. Method Participants included 765 non‐Hispanic White (NHW) and 859 non‐Hispanic Black (NHB) Iraq/Afghanistan‐era veterans. A structured interview established psychiatric diagnoses. Combat exposure and PTSD symptom severity were assessed via self‐report. Results The most common lifetime diagnoses were depression (39.2%), PTSD (38.4%), and alcohol dependence (24.38%). After correcting for multiple comparisons, no significant effects were observed on any of the outcomes among the NHW sample; however, within the NHB sample, significant gene × environment (G × E) interactions were observed for lifetime PTSD (P = .0029) and PTSD symptom severity (P = .0009). In each case, the APOE ε4 allele had no effect on the outcomes when combat exposure was low; however, when combat exposure was high, an additive effect was observed such that ε4 homozygotes exposed to high levels of combat reported the highest rates of PTSD (92%) and the worst symptom severity scores on the Davidson Trauma Scale (M = 79.5). Conclusions Although preliminary, these findings suggest that the APOE ε4 allele, in conjunction with exposure to high levels of combat exposure, may increase veterans’ risk for developing PTSD.