title: Apolipoprotein E gene polymorphism, alcohol use, and their interactions in combat-related posttraumatic stress disorder.
abstract: BACKGROUND
  The symptomatology of posttraumatic stress disorder (PTSD) is related not only to the intensity of the causative trauma, but also to alcohol use and genetic factors. Among the many candidate genes, the apolipoprotein E gene (APOE) is thought to be associated with stress reactivity.
  
  
  METHODS
  Korean veterans of the Vietnam War with (n = 128) or without (n = 128) PTSD participated in this study. The Clinician-Administered PTSD Scale and Combat Exposure Scale were administered, and the severity of alcohol use was assessed among these veterans. The APOE polymorphism and clinical variables of the subjects were compared, and associations between PTSD and potential explanatory variables were tested using logistic regression analysis.
  
  
  RESULTS
  Higher frequencies of APOE ε2 alleles and a greater number of individuals with the ε2 allele were found in the PTSD group. Among patients with PTSD, ε2-allele noncarriers consumed alcohol in greater amounts and more frequently than did ε2-allele carriers. Regression analysis revealed a significant interactional effect between harmful drinking and the absence of the ε2 allele associated with PTSD risk.
  
  
  CONCLUSIONS
  These results suggest that the APOE ε2 allele operates as a susceptibility gene for combat-related PTSD, with the relationship between alcohol use and PTSD differing according to the ε2-allele status. Future studies should determine the role of the APOE in adaptation to extreme stress, the development of PTSD, and comorbid alcohol-related disorders.
authors.affiliation: Department of Neuropsychiatry, Veterans Health Service Medical Center, Seoul, Republic of Korea; Department of Psychiatry, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Tae Yong
authors.initials: TY
authors.lastname: Kim
authors.forename: Hae Gyung
authors.initials: HG
authors.lastname: Chung
authors.forename: Han-Sang
authors.initials: HS
authors.lastname: Shin
authors.forename: Se Joo
authors.initials: SJ
authors.lastname: Kim
authors.forename: Jin Hee
authors.initials: JH
authors.lastname: Choi
authors.forename: Moon Yong
authors.initials: MY
authors.lastname: Chung
authors.forename: Suk Kyoon
authors.initials: SK
authors.lastname: An
authors.forename: Tai Kiu
authors.initials: TK
authors.lastname: Choi
authors.forename: Hyoung Seok
authors.initials: HS
authors.lastname: So
authors.forename: Hyun-Sang
authors.initials: HS
authors.lastname: Cho
mesh_terms: D000368:Aged; D000428:Alcohol Drinking / Q000235:genetics*; D053329:Apolipoprotein E2 / Q000235:genetics*; D016022:Case-Control Studies; D003130:Combat Disorders / Q000235:genetics*; D005787:Gene Frequency; D059647:Gene-Environment Interaction; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D012307:Risk Factors; D013313:Stress Disorders, Post-Traumatic / Q000235:genetics*; D014728:Veterans / Q000523:psychology*
chemical_list: D053329:Apolipoprotein E2
keywords: alcohol; apolipoprotein E; gene-environment interaction; genetic association; posttraumatic stress disorder; veterans