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Therapeutic Efficacy and Neural Mechanisms of tACS in Depression with Suicidal Ideation

Presented During:

Brain stimulation: Treatment and Modelling

Wednesday, June 25, 2025: 6:09 PM - 6:21 PM

Brisbane Convention & Exhibition Centre

Room: Great Hall

Poster No:

Submission Type:

Abstract Submission

Authors:

Yuanyuan Guo¹, Yue Zhao¹, Jiahua Zhang¹, Dongpeng Wu¹, Mengyao Dai¹, Shaoyang Wang¹, Wen Xie², Kai Wang¹, Yanghua Tian³

Institutions:

¹Department of Neurology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, ²Department of Psychology, Anhui Mental Health Center, Hefei, Anhui, ³Department of Neurology, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui

First Author:

Yuanyuan Guo
Department of Neurology, The First Affiliated Hospital of Anhui Medical University
Hefei, Anhui

Co-Author(s):

Yue Zhao
Department of Neurology, The First Affiliated Hospital of Anhui Medical University
Hefei, Anhui

Jiahua Zhang
Department of Neurology, The First Affiliated Hospital of Anhui Medical University
Hefei, Anhui

Dongpeng Wu
Department of Neurology, The First Affiliated Hospital of Anhui Medical University
Hefei, Anhui

Mengyao Dai
Department of Neurology, The First Affiliated Hospital of Anhui Medical University
Hefei, Anhui

Shaoyang Wang
Department of Neurology, The First Affiliated Hospital of Anhui Medical University
Hefei, Anhui

Wen Xie
Department of Psychology, Anhui Mental Health Center
Hefei, Anhui

Kai Wang
Department of Neurology, The First Affiliated Hospital of Anhui Medical University
Hefei, Anhui

Yanghua Tian
Department of Neurology, the Second Affiliated Hospital of Anhui Medical University
Hefei, Anhui

Introduction:

Suicidal ideation is a severe symptom of depression and a critical precursor to suicide, requiring effective interventions(Grant, 2018; May, 2015). Transcranial alternating current stimulation (tACS), a novel non-invasive neuromodulation technique, has shown promise in treating neuropsychiatric disorders(Miranda, 2013; Berényi, 2018; Wang, 2022). However, its efficacy in alleviating suicidal ideation in depression and the underlying mechanisms remain unclear. This study aims to evaluate the therapeutic effects of tACS on suicidal ideation and investigate its potential mechanisms.

Methods:

We conducted a randomized, double-blind, sham-controlled trial to assess the clinical efficacy and safety of tACS in treating depressive patients with suicidal ideation. Between September 2022 and November 2023, 44 patients were randomized to receive either active or sham high-definition tACS (n = 22 per group) for 30 minutes twice daily over seven consecutive days. The tACS protocol utilized a 2-mA electrode placed over F3 and four return electrodes positioned at Fp1, F7, C3, and Fz, delivering stimulation at the individual alpha frequency. The primary outcome was defined as the change in suicidal ideation measured by the Beck Scale for Suicidal Ideation (BSS) and Columbia-Suicide Severity Rating Scale (C-SSRS) (Weissman, 1979; Mann, 2011). Secondary outcomes included changes in depressive symptoms (measured by the 17-item Hamilton Depression Rating Scale and Montgomery- Åsberg Depression Rating Scale), anxiety (Hamilton Anxiety Rating Scale), anhedonia (Temporal Experience of Pleasure Scale), rumination (Ruminative Response Scale), risk decision-making function (Game of Dice Task), and alpha activity (assessed via resting-state electroencephalogram [rs-EEG]) (Arns, 2019; Lee, 2019). Statistical analyses were performed using Linear Mixed Effects Models to evaluate treatment effects, and correlation analyses were conducted to explore the relationships between changes in suicidal ideation and other clinical symptoms as well as rs-EEG metrics.

Results:

Twenty-two patients in the active tACS group and 21 in the sham group completed the study. Active tACS significantly reduced suicidal ideation, with group-by-time interaction effects for BSS-suicidal ideation (F = 14.47, p < 0.001, 95% CI: -3.39 to -1.08), BSS-suicidal risk (F = 4.15, p = 0.048, 95% CI: -5.23 to -0.10), and C-SSRS-intensity of ideation (F = 10.22, p = 0.003, 95% CI: -8.34 to -2.00). Moreover, tACS significantly improved depressive symptoms, anxiety, anhedonia, rumination, and risk decision-making performance. Rs-EEG analysis revealed that tACS reduced alpha power spectral density, functional connectivity, and alpha-beta coupling while increasing frontal alpha asymmetry. Furthermore, reductions in alpha power were positively correlated with decreases in suicidal ideation, suggesting that the modulation of alpha oscillations may mediate the therapeutic effects of tACS. This study also found that the intervention was well-tolerated, with no serious adverse events reported.

Conclusions:

TACS targeting the left dorsolateral prefrontal cortex significantly alleviated suicidal ideation in patients with depression, potentially through the modulation of alpha oscillations. These findings enhance our understanding of the therapeutic efficacy and neural mechanisms of tACS and highlight its potential as a feasible and efficacious intervention for depressive patients with suicidal ideation.

Brain Stimulation:

Non-invasive Electrical/tDCS/tACS/tRNS ¹

Disorders of the Nervous System:

Psychiatric (eg. Depression, Anxiety, Schizophrenia) ²

Novel Imaging Acquisition Methods:

EEG

Keywords:

Affective Disorders

Electroencephaolography (EEG)

Other - Transcranial alternating current stimulation(tACS);Suicidal ideation;Alpha frequency

^1|2Indicates the priority used for review

Abstract Information

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Please indicate below if your study was a "resting state" or "task-activation” study.

Resting state

Healthy subjects only or patients (note that patient studies may also involve healthy subjects):

Patients

Was this research conducted in the United States?

Were any human subjects research approved by the relevant Institutional Review Board or ethics panel? NOTE: Any human subjects studies without IRB approval will be automatically rejected.

Yes

Were any animal research approved by the relevant IACUC or other animal research panel? NOTE: Any animal studies without IACUC approval will be automatically rejected.

Not applicable

Please indicate which methods were used in your research:

EEG/ERP

Neuropsychological testing

Other, Please specify - tACS

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Other, Please list - EEGLAB

Provide references using APA citation style.

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Wang, H. (2022). Transcranial alternating current stimulation for treating depression: a randomized controlled trial. Brain, 145(1), 83–91.

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