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

Active beta-frequency transcranial alternating current stimulation: 20 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).

Sham 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).