Pre-treatment letter fluency performance predicts antidepressant response to transcranial direct current stimulation.
Transcranial direct current stimulation (tDCS) is a promising new treatment for depression, however, clinical trials to-date indicate variable efficacy, thereby raising the need to identify inter-individual predictors of response. In the current study we aimed to investigate pre-treatment neurocognitive performance as a predictor of antidepressant response to tDCS.



Data was pooled from five clinical trials, including two randomised controlled trials (RCTs), which investigated the antidepressant effects of anodal tDCS administered to the prefrontal cortex. Data from 57 patients were included in the analysis. Mood was assessed before and after an acute course of treatment using the Montgomery-Åsberg Depression Rating Scale. The following neurocognitive tests were administered prior to treatment: Simple and choice reaction time, the Symbol Digit Modalities Test (SDMT), Rey Auditory Verbal Memory Task (RAVLT), Digit Span, and the Controlled Oral Word Association Test (COWAT).



Better pre-treatment letter fluency performance measured using the COWAT predicted antidepressant response to tDCS after controlling for confounds.



Small sample size and analysis included data from both RCTs and open label studies.



Pre-treatment letter fluency performance, an ability subserved by the left prefrontal cortex, the primary site of stimulation, is a predictor of response for tDCS treatment for depression. This study highlights the importance of inter-individual neurobiological differences in mediating tDCS antidepressant effects.
School of Psychiatry, Black Dog Institute, University of New South Wales, Sydney, Australia. Electronic address: donel.martin@unsw.edu.au.
Donel M
DM
Martin
School of Psychiatry, Black Dog Institute, University of New South Wales, Sydney, Australia.
Kevin
K
Yeung
School of Psychiatry, Black Dog Institute, University of New South Wales, Sydney, Australia.
Colleen K
CK
Loo
D000328:Adult; D003863:Depression / Q000523:psychology / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D015201:Meta-Analysis as Topic; D008875:Middle Aged; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D065908:Transcranial Direct Current Stimulation; D016896:Treatment Outcome; D055815:Young Adult
Depression; Executive; Neurocognitive; Predictors; Transcranial direct current stimulation