J Affect Disord. 2026 Apr 3:121739. doi: 10.1016/j.jad.2026.121739. Online ahead of print.
ABSTRACT
BACKGROUND: Researchers have studied transcranial direct current stimulation (tDCS) as a possible treatment for major depressive disorder (MDD), especially for people with treatment-resistant depression (TRD). This systematic review and meta-analysis evaluate the effectiveness and safety of tDCS for TRD by analyzing data from randomized clinical trials.
METHODS: To evaluate the impact of tDCS on TRD, we adhered to the 2020 PRISMA guidelines and registered our protocol with PROSPERO (CRD42024606468). A comprehensive search was performed using keywords related to tDCS and TRD across six databases, focusing on English-language studies published until June 10, 2024. RCTs were included based on specific PICO criteria, with a thorough risk of bias assessment using the Cochrane ROB-2 tool. Statistical analyses were conducted using Stata-17 software.
RESULTS: A total of 448 studies were initially identified, with six studies (200 participants) meeting inclusion criteria for assessing immediate post-treatment effects of tDCS on TRD. Meta-analysis showed active tDCS significantly reduced depressive symptoms compared to sham (SMD: -1.17 [-1.85, -0.49]; P < 0.001). Significant outcome predictors included session number, age, male percentage, and duration. A follow-up analysis of delayed effects (30-day post-treatment), using four studies (154 participants), found no significant difference between active and sham tDCS (SMD: -0.12 [-1.98, 1.74]; P = 0.90).
CONCLUSIONS: This review suggests tDCS may provide modest, short-term benefits in TRD, but findings were inconsistent, highly heterogeneous, and based on limited small trials. Standardized, large-scale studies with optimized protocols and longer follow-up are needed to confirm efficacy and safety.
PMID:41936982 | DOI:10.1016/j.jad.2026.121739
