Neuroimaging mechanism of transcranial temporal stimulation in the treatment of adolescent depression with non-suicidal self-injury

INTERVENTION: Part 1: Single‐arm tTIS treatment group:The stimulation target is the right insular lobe; two pairs of electrodes are placed on the scalp, and each pair is used to transmit high‐frequency sine waves at frequencies of 2040 Hz and 2000 Hz, thereby generating a \"beating\" frequency of 40 Hz. Each session of stimulation lasts for 20 minutes, including 30‐second rising and falling phases at the start and end; this process is repeated twice a day for 5 days, for a total of 10 sessions.;Part 2: RCT – True tTIS group:The stimulation target is the right insular lobe; two pairs of electrodes are placed on the scalp, and each pair is used to transmit high‐frequency sine waves at frequencies of 2040 Hz and 2000 Hz, thereby generating a \"beating\" frequency of 40 Hz. Each session of stimulation lasts for 20 minutes, including 30‐second rising and falling phases at the start and end; this process is repeated twice a day for 5 days, for a total of 10 sessions.;Part 2: RCT‐pseudo tTIS group:Transcranial temporal stimulation( sham stimulation,0 mA); CONDITION: Depression PRIMARY OUTCOME: 24‐item Hamilton Depression Scale score, HAMD‐24;Ottawa Self‐injury Scale; SECONDARY OUTCOME: Bake Suicidual Ideation Scale;Function connection changes;Time to reaction or relief; INCLUSION CRITERIA: 1. Meet the DSM‐5 diagnostic criteria for major depressive disorder and also meet the DSM‐5 diagnostic criteria for non‐suicidal self‐injury (NSSI), with at least one NSSI behavior occurring within the past month. 2. No medication use within the past two weeks; or completion of at least a two‐week washout period before enrollment (if fluoxetine was taken, a one‐month washout is required). 3. Score >=20 on the 24‐item Hamilton Depression Rating Scale (HAMD‐24) and OSI >=15. 4. Adolescents aged 12‐18 years, both genders. 5. Han Chinese. 6. Right‐handed. 7. Willing to participate in this study and cooperate with follow‐up, with written informed consent signed by both the patient and their legal guardian.