Depression

What the evidence supports

Multiple randomized, sham-controlled trials and a meta-analysis support an antidepressant effect of active tDCS greater than sham — as a complementary therapy and under professional supervision.

• Meta-analysis (Shiozawa et al., 2014; 7 RCTs, n=259): effect size Hedges' g = 0.37 (95% CI 0.04–0.70); response OR 1.63; remission OR 2.5.
• International guideline (IFCN, Lefaucheur 2017): Level B — probable efficacy — for anodal left-DLPFC tDCS. No indication receives Level A (definite efficacy).
• Fully remote home RCT (Woodham/Fu, Nature Medicine, 2025; n=174): response ~58% vs ~38% with sham, validating remotely supervised home use.
• Drop-out comparable to sham; effect of a magnitude comparable to rTMS.

Strength and limits of the evidence

The evidence base for tDCS has grown steadily over the past two decades, with controlled clinical trials and meta-analyses supporting its use — particularly in depression, with the anode over the left DLPFC. International guidelines recognize the technique at Level B (probable efficacy), and recent studies, including supervised home use, continue to expand this body of evidence. As with any evolving therapy, results vary across studies and long-term data are still being consolidated. We present the evidence as it is: solid, growing, and without promises of guaranteed results.

Sources

• Shiozawa P, et al. Int J Neuropsychopharmacol. 2014;17:1443–1452.
• Lefaucheur J-P, et al. (IFCN). Clin Neurophysiol. 2017;128(1):56–92.
• Woodham RD, et al. Nat Med. 2025;31:87–95.
• Boggio PS, et al. 2008 (cited in the Newronika dossier).

Informational, non-promissory content. tDCS is a complementary therapy under professional supervision; results vary between individuals.