title: BDNF serum levels are not related to cognitive functioning in older depressed patients and controls.
abstract: BACKGROUND
  Depression and cognitive decline are highly prevalent in older persons and both are associated with low serum brain derived neurotrophic factor (BDNF). Mutual pathways of depression and cognitive decline in older persons may explain the overlap in symptoms and low serum BDNF. We hypothesized that serum BDNF levels are lower in depressed elderly with poor cognitive performance (global or specifically in working memory, speed of information processing, and episodic memory) compared to depressed elderly without cognitive impairment or non-depressed controls.
  
  
  METHODS
  BDNF Serum levels and cognitive functioning were examined in 378 depressed persons and 132 non-depressed controls from a large prospective study on late-life depression. The association between BDNF levels and each cognitive domain among the depressed patients was tested by four separate linear regression models adjusted for relevant covariates. An analysis of covariance (ANCOVA) was performed to compare BDNF serum levels in three groups (depression with cognitive impairment, depression without cognitive impairment, and non-depressed controls), when adjusted for potential confounders.
  
  
  RESULTS
  No significant linear association was found between BDNF and any of the four cognitive domains tested. There are no differences in BDNF levels between controls and depressed patients with or without cognitive impairment global or in specific domains after controlling for confounders.
  
  
  CONCLUSIONS
  BDNF serum levels in this cohort of older depressed patients and controls are not related to cognitive functioning. As BDNF is essential for the survival and functioning of neurons, its levels may remain normal in stages of disease where remission is achievable.
authors.affiliation: Department of Psychiatry,VU Medical Center / GGZ inGeest,Amsterdam,the Netherlands.
authors.forename: Annemiek
authors.initials: A
authors.lastname: Dols
authors.affiliation: Department of Psychiatry,VU Medical Center / GGZ inGeest,Amsterdam,the Netherlands.
authors.forename: Carisha S
authors.initials: CS
authors.lastname: Thesing
authors.affiliation: Department of Old Age Psychiatry,UPC KU Leuven,Kortenberg campus,Belgium.
authors.forename: Filip
authors.initials: F
authors.lastname: Bouckaert
authors.affiliation: University Center of Psychiatry,University Medical Center Groningen,University of Groningen,Groningen,the Netherlands.
authors.forename: Richard C
authors.initials: RC
authors.lastname: Oude Voshaar
authors.affiliation: Department of Psychiatry,VU Medical Center / GGZ inGeest,Amsterdam,the Netherlands.
authors.forename: Hannie C
authors.initials: HC
authors.lastname: Comijs
authors.affiliation: Department of Psychiatry,VU Medical Center / GGZ inGeest,Amsterdam,the Netherlands.
authors.forename: M L
authors.initials: ML
authors.lastname: Stek
mesh_terms: D000368:Aged; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood* / Q000502:physiology; D016022:Case-Control Studies; D003072:Cognition Disorders / Q000097:blood* / Q000503:physiopathology / Q000523:psychology; D003863:Depression / Q000097:blood* / Q000503:physiopathology / Q000523:psychology; D005260:Female; D006801:Humans; D007406:Interview, Psychological; D008297:Male; D009483:Neuropsychological Tests; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales
chemical_list: D019208:Brain-Derived Neurotrophic Factor
keywords: depressed