2026 ECNP Congress

PS04-4186

Efficacy of transcranial electrical therapy (tES) in adult attention deficit disorder: a systematic review

Luz María González Gualda — M. Alino Dies, N. Navarro Sirvent, K. Nieto-Rodriguez, M.J. Montes Lozano, P. Romero Rodenas, M. Lucas Perez-Romero · Complejo Hospitalario Universitario de Albacete- CHUA, Psychiatry, Albacete, Spain

2026 ECNP Congress

Introduction

Attention Deficit Hyperactivity Disorder. in adults has an estimated global prevalence of between 2.5% and 4% of the population (1), with a significant impact on executive functions, working memory, inhibitory control, and emotional regulation (2,3). Although pharmacological treatment with psychostimulants remains the standard, limitations such as adherence, cardiovascular side effects, and a high non-response rate have spurred interest in non-pharmacological alternatives (4). Transcranial direct current stimulation (tDCS) has emerged as a tool potentially capable of compensating for cognitive impairment, benefiting neuroplasticity and long-term outcomes (5). Transcranial electrical therapy encompasses several modalities: tDCS, transcranial alternating current stimulation (tACS), transcranial random noise stimulation (tRNS), and, less frequently, high-definition stimulation (HD-tDCS). This review synthesizes the evidence from the last five years from randomized controlled trials (RCTs), meta-analyses, and systematic reviews published in indexed psychiatry and neuroscience journals. Aim(s) of the study:Analyze the effectiveness of transcranial electrical therapy in Attention Deficit Hyperactivity Disorder.

Methods

A systematic literature search was conducted in the PubMed, PsycINFO, Embase, Cochrane Library, and Web of Science databases, covering the period from January 2020 to May 2026. The following terms were used: “transcranial electric stimulation,” “tDCS,” “tACS,” “tRNS,” “adult ADHD,” “attention-deficit hyperactivity disorder,” “non-invasive brain stimulation,” and their Boolean combinations. Only studies in adults (≥18 years) diagnosed with ADHD according to DSM-5 or ICD-10/11 criteria, published in indexed journals (JAMA Psychiatry, Molecular Psychiatry, Brain Stimulation, Frontiers in Psychiatry, Brain Sciences, among others), were included. Results and conclusions: Test-assisted stimulation (tES), particularly transcranial direct current stimulation (tDCS), shows promising results as an adjunctive intervention in adults with ADHD, with growing evidence positioning it as a low-risk, non-pharmacological alternative. The findings of the TUNED trial (JAMA Psychiatry, 2022) and meta-analytic syntheses from 2024–2026 provide the strongest empirical basis to date. Transcranial direct current stimulation (tACS) is emerging as a second-generation modality with distinct mechanisms (oscillatory modulation), supported by a randomized controlled trial (RCT) published in Molecular Psychiatry (2025) with a large effect size.Future advances should prioritize protocol standardization, the implementation of neuronavigation to personalize the stimulation target, the study of biological response variability (genomics, neuroimaging), and the synergistic combination of tES with cognitive-behavioral interventions or executive function training. The potential of remotely monitored home devices, demonstrated in the TUNED trial, opens a clinically relevant avenue for expanding access to this type of intervention.

Limitations

Despite the remarkable progress in the field during the analyzed period, significant methodological limitations persist. Heterogeneity among studies is considerable, affecting stimulation parameters (intensity, duration, number of sessions, interval between sessions), electrode arrays, outcome scales.A recently published systematic review and network meta-analysis noted that while one synthesis found improvements in inhibitory control, working memory, and inattention with tDCS, tACS, and tRNS compared to sham, another meta-analysis concluded that tDCS does not produce significant effects on inhibitory control and inattention, highlighting the contradictions arising from the heterogeneity of the underlying studies. The lack of standardization in protocols makes it difficult to directly compare studies and to translate findings into clinical practice.

References

  1. Gholamali Nezhad, F., Martin, J., Tassone, V. K., Swiderski, A., Demchenko, I., Khan, S., Chaudhry, H. E., Palmisano, A., Santarnecchi, E., & Bhat, V. (2024). Transcranial alternating current stimulation for neuropsychiatric disorders: A systematic review of treatment parameters and outcomes. Frontiers in Psychiatry, 15, Article 1419243. https://doi.org/10.3389/fpsyt.2024.1419243
  2. Li, Hou, Fan, & Chen. (2026). The efficacy and safety of transcranial direct current stimulation in patients with ADHD: A systematic review and meta-analysis. Frontiers in Psychiatry. https://doi.org/10.3389/fpsyt.2026.1747588
  3. Salehinejad,. M. A.,Ghanavati, E., Glinski, B., Nitsche, M. A., & Najafi, M. (2024). Noninvasive brain stimulation for improving cognitive deficits and clinical symptoms in attention-deficit/hyperactivity disorder: A systematic review and meta-analysis. Brain Sciences, 14(12), Article 1237. https://doi.org/10.3390/brainsci14121237
  4. Wang et al (2025). Comparative efficacy of non-invasive brain stimulation for attention-deficit/hyperactivity disorder: A systematic review and network meta-analysis. https://doi.org/10.3390/
  5. Yang, D., Shin, Y.-I., & Hong, K.-S. (2021). Systemic review on transcranial electrical stimulation parameters and EEG/fNIRS features for brain diseases. Frontiers in Neuroscience, 15, Article 629323. https://doi.org/10.3389/fnins.2021.629323