Title:Does Non-Invasive Brain Stimulation Improve Cognition in Major Depressive Disorder? A Systematic Review
Volume: 13
Issue: 10
Author(s): Gabriel Tortella, Priscila M.L. Selingardi, Marina L. Moreno, Beatriz P. Veronezi and Andre R. Brunoni
Affiliation:
Keywords:
Cognitive assessment, major depressive disorder, systematic review, transcranial direct current stimulation,
transcranial magnetic stimulation, working memory.
Abstract: Non-invasive brain stimulation (NIBS) techniques, such as repeated transcranial magnetic stimulation (rTMS)
and transcranial direct current stimulation (tDCS), have been increasingly used in different contexts to improve cognitive
performance and ameliorate depression symptoms. Considering that major depression is usually accompanied by
cognitive deficits, NIBS technique could be also helpful to improve cognition in depressed patients. In this systematic
review, we researched for articles published in PubMed/MEDLINE from the first date available to June 2014 that
assessed cognitive performance in patients with depression before and after NIBS. Out of 191 references, 25 (16 for rTMS
and 9 for tDCS) studies matched our eligibility criteria. Non-invasive brain stimulation interventions, such as rTMS and
tDCS seem to be a promising tool for cognitive enhancement in MDD, although several issues and biases (e.g., blinding
issues, tests without correction for multiple comparisons, placebo effects and exploratory analyses, practice effects) hinder
us to conclude that NIBS technique improve cognition in patients with depression. We discussed possible shortcomings of
the included studies, such as the use of different depression treatment protocols, the possibility that some findings were
false-positive results of the employed cognitive tasks and whether cognition improvement could have been an
epiphenomenon secondary to depression improvement. To conclude, whereas these non-pharmacological, non-invasive
techniques are particularly appealing for cognitive improvement in depression, further studies are still warranted to
disentangle whether NIBS technique induce positive effects on cognition beyond their antidepressant effects.
