title: Elevated Brain-Derived Neurotrophic Factor Correlates Negatively with Severity and Duration of Major Depressive Episodes.
abstract: OBJECTIVE
  Major depressive disorder is a neuropsychiatric condition associated with neurochemical changes that alter levels of neurotrophins. We aimed to measure serum levels of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in patients experiencing their first episode of major depression and to examine those levels in relation to the severity and duration of the depressive episode.
  
  
  METHODS
  We recruited 85 participants: 44 drug-free patients with major depression (35 women, 9 men) and 41 healthy controls (32 women, 9 men). We used the Hamilton Rating Scale for Depression to assess the severity of the patients' depression. We assessed the controls' mental health according to Diagnostic and Statistical Manual of Mental Disorders, 4th ed, criteria. To assess all participants' stress levels, we used the Holmes and Rahe stress scale. We measured all participants' serum BDNF and NGF levels via enzyme-linked immunosorbent assay.
  
  
  RESULTS
  The mean stress score was significantly higher in the patients than the controls (P=0.03). The patients had higher serum BDNF than the controls (P=0.001), but similar NGF levels. BDNF levels correlated negatively with symptom severity (r=-0.33, P=0.03) and duration (r=-0.2, P=0.06). NGF levels did not correlate with stress or with severity or duration of depressive episode.
  
  
  CONCLUSIONS
  These findings suggest that an elevated serum BDNF level may contribute to the pathophysiology of major depressive disorder. The findings also indicate a possible role for BDNF in altering the clinical course of the condition.
authors.affiliation: *Department of Nutrition †Research Center of Psychiatry and Behavioral Sciences (RCPBS) ‡Health Management Center, Tabriz University of Medical Sciences, Tabriz, Islamic Republic of Iran.
authors.forename: Sorayya
authors.initials: S
authors.lastname: Kheirouri
authors.forename: Seyed Gholamreza
authors.initials: SG
authors.lastname: Noorazar
authors.forename: Mohammad
authors.initials: M
authors.lastname: Alizadeh
authors.forename: Leyli
authors.initials: L
authors.lastname: Dana-Alamdari
mesh_terms: D000328:Adult; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood*; D016022:Case-Control Studies; D003865:Major Depressive Disorder / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020932:Nerve Growth Factor / Q000097:blood*; D012720:Severity of Illness Index; D013997:Time Factors; D055815:Young Adult
chemical_list: D019208:Brain-Derived Neurotrophic Factor; C502240:NGF protein, human; C579455:BDNF protein, human; D020932:Nerve Growth Factor