title: Duration of last depressive episode may influence serum BDNF levels in remitted patients with major depression.
abstract: BACKGROUND
  Brain-derived neurotrophic factor (BDNF) may have an important role in the pathophysiology of depression. Previous studies indicate that serum BDNF levels were lower in patients with depression and increased after treatment with antidepressants. However, results of studies on serum BDNF levels in remitted patients with depression have been inconsistent. The purpose of the present study was to determine which factors influence the alteration of serum BDNF levels in depression in the remitted state.
  
  
  METHODS
  Serum BDNF levels were evaluated in 75 remitted inpatients with major depressive disorder (MDD) and 108 controls. Multiple regression analyses were conducted using serum BDNF levels as the dependent variable; and the number of episodes, Hamilton Rating Scale for Depression score at admission, or duration of last depressive episode as independent variables.
  
  
  RESULTS
  Serum BDNF levels were lower in remitted patients with MDD than in controls (P < .001). Multiple regression analysis showed a significant effect between the duration of the last depressive episode and serum BDNF levels (P < .022).
  
  
  CONCLUSIONS
  Serum BDNF levels in remitted patients with MDD did not recover to the level of healthy controls, and lower serum BDNF levels were influenced by a longer duration of last depressive episode. It is possible that persistent hippocampal reduction in remitted depression may be caused by lower BDNF levels associated with a longer duration of the last depressive episode.
authors.affiliation: Department of Psychiatry, Juntendo University, School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Takebayashi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Maeshima
authors.forename: Hajime
authors.initials: H
authors.lastname: Baba
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Nakano
authors.forename: Emi
authors.initials: E
authors.lastname: Satomura
authors.forename: Yohei
authors.initials: Y
authors.lastname: Kita
authors.forename: Yuki
authors.initials: Y
authors.lastname: Namekawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nomoto
authors.forename: Toshihito
authors.initials: T
authors.lastname: Suzuki
authors.forename: Heii
authors.initials: H
authors.lastname: Arai
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000928:Antidepressive Agents / Q000627:therapeutic use; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood*; D016022:Case-Control Studies; D003865:Major Depressive Disorder / Q000097:blood* / Q000188:drug therapy / Q000503:physiopathology; D005260:Female; D006801:Humans; D007297:Inpatients; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D012044:Regression Analysis
chemical_list: D000928:Antidepressive Agents; D019208:Brain-Derived Neurotrophic Factor