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

Effects of Combined taVNS and tACS on Adolescents With Non-Suicidal Self-Injury: A Randomized Controlled Trial

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.

Inclusion Criteria:

• Meet the proposed diagnostic criteria for non-suicidal self-injury (NSSI) in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), with ≥5 documented self-injury episodes and at least one incident within the past month as assessed by the Adolescent Non-Suicidal Self-Injury Assessment Questionnaire (ANSAQ)
• Aged 12-18 years
• Right-handed
• Possess formal education experience sufficient to comprehend experimental protocols
• Normal or corrected-to-normal binocular visual acuity
• Voluntarily participate with legal guardians providing written informed consent

Exclusion Criteria:

• Montreal Cognitive Assessment (MoCA) score < 26
• History of suicide attempts
• History of epilepsy, brain surgery, tumors, or clinically significant head trauma
• History of substance abuse or severe physical diseases
• Received physical or psychological interventions within the past three months