title: Transcranial direct current stimulation (tDCS) in the treatment of depression: Systematic review and meta-analysis of efficacy and tolerability.
abstract: BACKGROUND
  Transcranial direct current stimulation (tDCS) is a potential alternative treatment option for major depressive episodes (MDE).
  
  
  OBJECTIVE
  We address the efficacy and safety of tDCS in MDE.
  
  
  METHODS
  The outcome measures were Hedges' g for continuous depression ratings, and categorical response and remission rates.
  
  
  RESULTS
  A random effects model indicated that tDCS was superior to sham tDCS (k=11, N=393, g=0.30, 95% CI=[0.04, 0.57], p=0.027). Adjunctive antidepressant medication and cognitive control training negatively impacted on the treatment effect. The pooled log odds ratios (LOR) for response and remission were positive, but statistically non-significant (response: k=9, LOR=0.36, 95% CI[-0.16, 0.88], p=0.176, remission: k=9, LOR=0.25, 95% CI [-0.42, 0.91], p=0.468). We estimated that for a study to detect the pooled continuous effect (g=0.30) at 80% power (alpha=0.05), a total N of at least 346 would be required (with the total N required to detect the upper and lower bound being 49 and 12,693, respectively).
  
  
  CONCLUSIONS
  tDCS may be efficacious for treatment of MDE. The data do not support the use of tDCS in treatment-resistant depression, or as an add-on augmentation treatment. Larger studies over longer treatment periods are needed.
authors.affiliation: Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, University Department of Psychiatry, Academic Centre, College Keep, 4-12 Terminus Terrace, Southampton SO14 3DT, United Kingdom; Avon & Wiltshire Partnership NHS Trust, Jenner House, Langley Park, Chippenham SN15 1GG, Wiltshire, United Kingdom. Electronic address: dan@soton.ac.uk.
authors.forename: Daniel
authors.initials: D
authors.lastname: Meron
authors.affiliation: Psychology, Faculty of Social, Human and Mathematical Sciences, University of Southampton, Southampton, United Kingdom. Electronic address: nick.hedger@soton.ac.uk.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Hedger
authors.affiliation: Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, University Department of Psychiatry, Academic Centre, College Keep, 4-12 Terminus Terrace, Southampton SO14 3DT, United Kingdom; Psychology, Faculty of Social, Human and Mathematical Sciences, University of Southampton, Southampton, United Kingdom. Electronic address: M.J.GARNER@soton.ac.uk.
authors.forename: Matthew
authors.initials: M
authors.lastname: Garner
authors.affiliation: Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, University Department of Psychiatry, Academic Centre, College Keep, 4-12 Terminus Terrace, Southampton SO14 3DT, United Kingdom; University Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa. Electronic address: D.S.Baldwin@soton.ac.uk.
authors.forename: David S
authors.initials: DS
authors.lastname: Baldwin
mesh_terms: D003865:Major Depressive Disorder / Q000628:therapy*; D006801:Humans; D017063:Outcome Assessment, Health Care / Q000379:methods*; D065908:Transcranial Direct Current Stimulation / Q000009:adverse effects / Q000379:methods*
keywords: Cognitive control training; Depression; Meta-analysis; Non-pharmacological therapies; Remission; Response; Systematic review; Transcranial direct current stimulation; tDCS