title: Brain-derived neurotrophic factor (BDNF) Val66Met and adulthood chronic stress interact to affect depressive symptoms.
abstract: BACKGROUND
  BDNF Val66Met by chronic stress interaction has been studied using childhood stress as a moderator, but has not been widely studied using chronic stress in adulthood.
  
  
  METHODS
  Two independent samples were used: Duke-CG (238 Caucasians) and MESA (5524 Caucasians, African Americans and Hispanics). Chronic stress in Duke-CG was operationalized as having primary caregiving responsibility for a spouse or relative with diagnosed Alzheimer's disease or other major dementia; chronic stress in MESA was defined using chronic burden score constructed from self-reported problems of health (self and someone close), job, finance and relationships. CES-D scale was the measure of depression in both samples. The BDNF Val66Met by adulthood chronic stress interaction predicting CES-D was examined using linear regression, adjusted for covariates.
  
  
  RESULTS
  The main effect of BDNF Val66Met genotype on CES-D scores was non-significant (ps > 0.607) but the adulthood chronic stress indicator was significant (ps < 0.001) in both samples. The BDNF Val66Met genotype by adulthood chronic stress interaction was also significant (ps < 0.039) in both samples. The impact of chronic stress in adulthood on CES-D scores was significantly larger in Val/Val genotype individuals than Met carriers.
  
  
  CONCLUSIONS
  We found in two independent samples that depression levels increased significantly more as a function of adulthood chronic stress Val/Val genotype carriers than Met carriers. Individuals with the Val/Val genotype and chronic stress exposure could be targeted for interventions designed to reduce risk of depression if this finding is confirmed in future studies.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27705, USA. rong.jiang@duke.edu
authors.forename: Rong
authors.initials: R
authors.lastname: Jiang
authors.forename: Beverly H
authors.initials: BH
authors.lastname: Brummett
authors.forename: Michael A
authors.initials: MA
authors.lastname: Babyak
authors.forename: Ilene C
authors.initials: IC
authors.lastname: Siegler
authors.forename: Redford B
authors.initials: RB
authors.lastname: Williams
mesh_terms: D000293:Adolescent; D000368:Aged; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics*; D015331:Cohort Studies; D003863:Depression / Q000150:complications / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D016014:Linear Models; D008297:Male; D008715:Methionine / Q000235:genetics*; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D013315:Stress, Psychological / Q000150:complications / Q000235:genetics*; D011795:Surveys and Questionnaires; D014633:Valine / Q000235:genetics*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D008715:Methionine; D014633:Valine