Effects of taVNS Combined With tACS on Adolescents With Non-Suicidal Self-Injury

Summary

NSSI behavior is highly prevalent among adolescents, and its mechanisms are closely associated with attentional bias toward self-injury-related information and impulsivity, both of which may be related to reduced dlPFC activation levels. Introducing taVNS as a priming stimulus to pre-regulate brain state and optimize subsequent tACS treatment response provides a novel approach to addressing inconsistent intervention effects. Simultaneously, this facilitates a shift in the brain from passive stimulus reception to active state regulation, offering important theoretical foundations for developing more precise and efficient cross-modal neuromodulation therapies.This study aims to systematically validate the efficacy of a combined protocol using taVNS as a priming modality followed by tACS over the left dlPFC through a randomized controlled trial (RCT). The investigators hypothesize that:

① Compared to tACS intervention alone, this combined approach will not only demonstrate non-inferiority in overall therapeutic efficacy but, more importantly, significantly reduce inter-individual variability in treatment response to tACS. This would mitigate the issue of high clinical response heterogeneity and enhance the stability and predictability of treatment outcomes.

② Early behavioral biomarkers of intervention response are anticipated: Immediate improvements in attentional bias following a single combined intervention session will significantly predict reductions in the frequency and intensity of Non-Suicidal Self-Injury (NSSI) after a full course (14 sessions) of treatment. This suggests that early positive changes in cognitive function could serve as valid indicators predicting long-term clinical efficacy, offering a critical time window for implementing individualized treatment adjustments.

③ The study will elucidate the effects of the taVNS-primed combined tACS treatment on neuroimaging mechanisms in adolescents with NSSI.

Conditions

• Non-suicidal Self-injury

Interventions

DEVICE

25Hz、300us transcutaneous auricular vagus nerve stimulation and10hz transcranial alternating current stimulation

The active taVNS stimulation was applied to the cymba conchae, an area exclusively innervated by the auricular branch of the vagus nerve. Active taVNS stimulation protocol was set as follows: pulse width of 300 μs, frequency of 25 Hz, and current intensity adjusted based on each participant's individual threshold, set at 80% of the sensory threshold. The stimulation duration was 15 minutes. Active 10hz transcranial alternating current stimulation: 10 Hz tACS delivered through a 4×1-ring high-definition electrode montage centered on left DLPFC (F3), 2 mA peak-to-peak, 100 % intensity, gradually ramped up over 30 s, maintained for 20 min, then ramped down over 30 s; two sessions per day with at least 4 h between sessions, repeated for 7 consecutive days (14 total sessions).

DEVICE

sham 25Hz、300us transcutaneous auricular vagus nerve stimulation and 10hz transcranial alternating current stimulation

The sham taVNS stimulation was placed on the earlobe. The two procedures were indistinguishable in terms of appearance, ensuring effective blinding. The stimulation duration was 15 minutes. Active 10HZ transcranial alternating current stimulation: 10 Hz tACS delivered through a 4×1-ring high-definition electrode montage centered on left DLPFC (F3), 2 mA peak-to-peak, 100 % intensity, gradually ramped up over 30 s, maintained for 20 min, then ramped down over 30 s; two sessions per day with at least 4 h between sessions, repeated for 7 consecutive days (14 total sessions).

DEVICE

active 25Hz、300us transcutaneous auricular vagus nerve stimulation and sham10hz transcranial alternating current stimulation

The active taVNS stimulation was applied to the cymba conchae, an area exclusively innervated by the auricular branch of the vagus nerve. active taVNS stimulation protocol was set as follows: pulse width of 300 μs, frequency of 25 Hz, and current intensity adjusted based on each participant's individual threshold, set at 80% of the sensory threshold. The stimulation duration was 15 minutes. Sham 10HZ transcranial alternating current stimulation: identical 4×1-ring high-definition electrode montage centered on left DLPFC (F3), 2 mA peak-to-peak current ramped up over 30 s and immediately ramped down to 0 mA, followed by 19.5 min of no stimulation to match the 20-min session duration of active tACS; delivered twice daily (≥4 h apart) for 7 consecutive days (14 total sessions).

Sponsors & Collaborators

• Anhui Medical University

  lead OTHER

Principal Investigators

• Hongyan Zhu · School of Mental Health and Psychological Sciences, Anhui Medical University

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

12 Years

Max Age

22 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2025-10-16

Primary Completion

2027-10-01

Completion

2027-10-01

Countries

• China

Study Locations