# Transcranial Direct Current Stimulation (tDCS) in the Treatment of Youth Depression: Integrating Literature Review Insights in a Pilot Clinical Trial

## TL;DR

This study explores the use of transcranial direct current stimulation (tDCS) as a potential treatment for youth depression, finding it safe and feasible with high session attendance and no serious adverse events.

## Contribution

The first study to review and pilot tDCS implementation in youth depression, providing a framework for future trials.

## Key findings

- tDCS showed high session attendance and retention in a pilot trial with no dropouts or serious adverse events.
- Both active and sham tDCS groups showed reduced depression symptoms, with a greater reduction in the active group.
- Decentralized tDCS administration introduced variability in adherence, highlighting a need for standardized protocols.

## Abstract

What are the main findings?

This study identified transcranial direct stimulation (tDCS) as a promising and feasible treatment modality for youth depression. A systematic review conducted up until 20 November 2024 identified fourteen eligible registered/ published studies in tDCS for youth depression. Among the limited clinical data available, two trials demonstrated substantial symptom improvement. However, recruitment challenges and high risks of bias underscore the need for robust evidence supporting the feasibility of conducting tDCS RCTs in this population.This pilot trial demonstrated high session attendance and retention rates with no dropouts or serious adverse events during the five-day, 30 min, 2 mA tDCS protocol.Decentralised administration of tDCS required prompting in some cases and may have introduced variability in adherence.

What are the implications of the main findings?

tDCS has the potential as a safe and acceptable intervention for youth depressionFirst study to review and pilot youth tDCS implementationProvides practical insights into translating neuromodulation reviews into a pilot trialAlthough not powered to detect efficacy, it offers a framework for designing future trialsEmphasizes need to evaluate long-term safety- specifically the absence of unintended outcomes of tDCS.

What are the main findings?

This study identified transcranial direct stimulation (tDCS) as a promising and feasible treatment modality for youth depression. A systematic review conducted up until 20 November 2024 identified fourteen eligible registered/ published studies in tDCS for youth depression. Among the limited clinical data available, two trials demonstrated substantial symptom improvement. However, recruitment challenges and high risks of bias underscore the need for robust evidence supporting the feasibility of conducting tDCS RCTs in this population.

This pilot trial demonstrated high session attendance and retention rates with no dropouts or serious adverse events during the five-day, 30 min, 2 mA tDCS protocol.

Decentralised administration of tDCS required prompting in some cases and may have introduced variability in adherence.

What are the implications of the main findings?

tDCS has the potential as a safe and acceptable intervention for youth depression

First study to review and pilot youth tDCS implementation

Provides practical insights into translating neuromodulation reviews into a pilot trial

Although not powered to detect efficacy, it offers a framework for designing future trials

Emphasizes need to evaluate long-term safety- specifically the absence of unintended outcomes of tDCS.

Background: Youth (ages 16–25) is a key window for mental health interventions, as depression rates significantly increase during this developmental stage. However, transcranial direct current stimulation (tDCS) application in youth depression remains underexplored. To reduce the uncertainty of a future trial, we conducted a review and a pilot randomised controlled trial (RCT) of tDCS for youth depression. Methods: Following the PRISMA guidelines, the first part of this study was a review across databases including PubMed, MEDLINE, PsychInfo, CINAHL, Open Access Theses and Dissertations (OATD), WanFang Data, Chinese Medical Journal, and clinical trial registries up to 20 November 2024, on tDCS treatment for youth depression. The second part of this study was a double-blind pilot RCT assessing feasibility, by comparing active tDCS (five daily 30 min 2 mA anodal tDCS applications over the left dorsolateral–pre-frontal-cortex (DLPFC) with sham tDCS. Feasibility outcomes included recruitment, data collection, attendance, retention and randomisation. Outcomes also included depression severity using the Hamilton Depression Rating Scale (HDRS), safety, tolerability, acceptability, and adequacy of blinding. Mann–Whitney U tests were used for between-group comparison. Results: Fourteen eligible studies were identified, with a pooled HDRS reduction of −9.6 (95% CI: −11.2 to −8.1, p < 0.001), though high risks of bias indicated a research gap. Using parameters derived from the review, we conducted a pilot RCT in which 20 youths were screened and 8 were randomised (aged 16–24; 3 females, 5 males). All randomised participants completed their assigned sessions without dropout or protocol discontinuations. Blinding was adequate, and participants’ willingness to engage improved over time. Both groups showed reductions in HDRS, with a greater mean reduction in the active group (−4.75 ± 2.96) compared to the sham group (−3.75 ± 3.78). No serious adverse events occurred, with only mild headaches and tingling reported. The tolerability profile was comparable. However, the decentralised administration of sessions may have introduced inconsistent tDCS applications. Conclusions: This review highlights a lack of RCTs on tDCS for youth depression. Our pilot trial demonstrates the feasibility of a sham-controlled design in youth depression, justifying larger-scale trials to evaluate the efficacy of tDCS in this population.