The Impact of Beta-band Transcranial Alternating Current Stimulation (tACS) on Impulse Inhibition in Adolescents With Non-suicidal Self-injury

This clinical trial aims to determine whether beta-band transcranial alternating current stimulation (tACS) can improve impulse inhibition in adolescents with non-suicidal self-injury (NSSI) and to evaluate its safety. The primary questions it seeks to answer are: * Can beta-band tACS significantly reduce the frequency of self-injury and scores on impulsivity scales in adolescents with NSSI? * What discomfort or medical issues may participants experience during tACS intervention? Researchers will compare beta-band tACS with sham stimulation (a procedure that mimics the real stimulation without delivering effective current) to verify its efficacy. Participants will: * Receive two sessions of either tACS or sham stimulation daily, spaced 4 hours apart, for 7 consecutive days (14 sessions in total). * Undergo scale assessments, behavioral tasks, and eye-tracking tests before and after the intervention. * Record any self-injury episodes and adverse reactions, with continuous monitoring and psychological support provided by a professional team.