title: BDNF blood levels after electroconvulsive therapy in patients with mood disorders: a systematic review and meta-analysis.
abstract: OBJECTIVE
  To evaluate whether electroconvulsive therapy (ECT), a very effective non-pharmacological treatment for mood disorders, induces neurotrophic effects, indexed by the measurement of peripheral brain-derived neurotrophic factor (BDNF) levels.
  
  
  METHODS
  Systematic review and meta-analysis of clinical trials published in PubMed/Medline from the first date available to October 2013. We included studies measuring pre- and post-BDNF blood levels under ECT in patients with mood disorders in the acute depressive episode.
  
  
  RESULTS
  Eleven studies (n = 221 subjects) were eligible. These studies enrolled subjects with unipolar, bipolar and psychotic depression and varied regarding electrode placement (unipolar vs. bipolar) and previous use of pharmacotherapy. Nonetheless, BDNF significantly increased after ECT (Hedges' g pooled, random-effects model of 0.354; 95% CI = 0.162-0.546). The results were robust according to sensitivity analysis and Begg's funnel plot did not suggest publication bias. Meta-regression results did not show association of the outcome with any clinical and demographic variable, including depression improvement.
  
  
  CONCLUSIONS
  Our meta-analysis indicates that, similar to pharmacological interventions, peripheral BDNF increases after ECT treatment. The lack of correlation between BDNF increasing and depression improvement suggests that ECT induces neurotrophic effects regardless of clinical response in depression.
authors.affiliation: Laboratory of Neuroscience (LIM27), Department and Institute of Psychiatry, University of São Paulo , São Paulo , Brazil.
authors.forename: André R
authors.initials: AR
authors.lastname: Brunoni
authors.forename: Chris
authors.initials: C
authors.lastname: Baeken
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Machado-Vieira
authors.forename: Wagner F
authors.initials: WF
authors.lastname: Gattaz
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: Vanderhasselt
mesh_terms: D019208:Brain-Derived Neurotrophic Factor / Q000097:blood*; D004565:Electroconvulsive Therapy; D006801:Humans; D019964:Mood Disorders / Q000097:blood* / Q000628:therapy*
chemical_list: D019208:Brain-Derived Neurotrophic Factor
keywords: brain-derived neurotrophic factor; electroconvulsive therapy; meta-analysis; mood disorders; systematic review