title: Increased BDNF levels in long-term bipolar disorder patients.
abstract: BACKGROUND
  Bipolar disorder (BD) is a prevalent, chronic and progressive illness. There is a growing body of evidence indicating that brain-derived neurotrophic factor (BDNF) plays an important role in the pathophysiology of BD.
  
  
  OBJECTIVE
  The aim of this study was to evaluate BDNF plasma levels in BD patients with long term illness in comparison with controls.
  
  
  METHODS
  87 BD type I patients and 58 controls matched by age, gender and education level were enrolled in this study. All subjects were assessed by the Mini-International Neuropsychiatric Interview and the patients by the Young Mania Rating Scale and the Hamilton Depression Rating Scale. The plasma levels of BDNF were measured by ELISA.
  
  
  RESULTS
  On average, patients had suffered from BD for 23.4 years. In comparison with controls, BD patients with mania presented a 1.90-fold increase in BDNF plasma levels (p = .001), while BD patients in remission presented a 1.64-fold increase in BDNF plasma levels (p = .03). BDNF plasma levels were not influenced by age, length of illness or current medications.
  
  
  CONCLUSIONS
  The present study suggests that long-term BD patients exhibit increased circulating levels of BDNF.
authors.affiliation: Graduate Program in Neurosciences, Universidade Federal de Minas Gerais, Brazil.
authors.forename: Izabela Guimarães
authors.initials: IG
authors.lastname: Barbosa
authors.forename: Natália Pessoa
authors.initials: NP
authors.lastname: Rocha
authors.forename: Aline Silva de
authors.initials: AS
authors.lastname: Miranda
authors.forename: Rodrigo Barreto
authors.initials: RB
authors.lastname: Huguet
authors.forename: Moisés Evandro
authors.initials: ME
authors.lastname: Bauer
authors.forename: Helton José
authors.initials: HJ
authors.lastname: Reis
authors.forename: Antônio Lúcio
authors.initials: AL
authors.lastname: Teixeira
mesh_terms: D000367:Age Factors; D015415:Biomarkers / Q000097:blood; D001714:Bipolar Disorder / Q000097:blood* / Q000503:physiopathology; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood*; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D013997:Time Factors
chemical_list: D015415:Biomarkers; D019208:Brain-Derived Neurotrophic Factor