Intervention Effect of High-Definition Transcranial Alternating Current Stimulation (HD-tACS) on Non-suicidal Self-injury (NSSI)

To investigate the intervention effect of high-definition transcranial alternating current stimulation (HD-tACS) on patients with Non-suicidal Self-injury (NSSI) and its underlying neural mechanism by magnetic resonance imaging (MRI).

Forty patients with Non-suicidal Self-injury (NSSI) diagnosed by DSM-5 were recruited from the Second Affiliated Hospital of Anhui Medical University. All participants underwent a structured interview and routine laboratory examination before and after receiving high-definition transcranial alternating current stimulation (HD-tACS) treatment after meeting the inclusion criteria and obtaining informed consent. Each participant will complete the clinical evaluation, magnetic resonance imaging (MRI), and HD-tACS treatment conducted by trained researchers at the Second Affiliated Hospital of Anhui Medical University. All the participants were randomized (1:1) to receive an "active HD-tACS" or "sham HD-tACS" treatment protocol. tACS: the central electrode was placed over F3 with return electrodes placed at Fp1, Fz, F7 and C3. Fourteen 2-mA sessions (ramp-up and ramp-down periods of 15 and 15 seconds, respectively) were applied for 20 minutes per session, twice daily over 7 consecutive days, and the stimulus frequency was set as individual alpha frequency (IAF). Sham HD-tACS was delivered using the same protocol and current intensity, but the period of active stimulation was only during the ramp-up and ramp-down periods of 15 and 15 seconds. Before and after the treatments, the patients received a battery measure of neuropsychological tests, and MRI scans in multimodalities. The neuropsychological assessment included the Ottawa Self-injury Inventory (OSI), the Adolescent Non-suicidal Self-injury Assessment Questionnaire (ANSAQ), the Hamilton Depression Rating Scale (HAMD), the Hamilton Anxiety Rating Scale (HAMA), and Patient Health Questionnaire-15 (PHQ-15) etc.Multimodal MRI includes 3D-T1, rs-fMRI, and DTI. The symptoms of the patients were followed up one and two months after the end of treatments.