Temporal Interference Stimulation (TIS) has been successfully used to help patients with depression. However, its role in alleviating self injuries remained uncertain. This trial will compare the effectiveness of TIS to a placebo control on non-suicidal self injury (NSSI) in patients with major depressive disorder(MDD).

The study will evaluate the efficacy and safety of TIS in depressive patients with NSSI behaviors by measuring changes in clinical ratings at baseline, after all the treatments, and 2 weeks, 4 weeks, 8 weeks after treatment. 60 inpatients will be randomized to receive active or sham interventions administered to the right subgenual anterior cingulate cortex. The treatment will apply TIS involving 2x daily at 30 minutes for 5-7 days.

Changes in mood from baseline to the end of the study will be measured with The Hamilton Rating Scale for Depression-17 item (HAMD-17), Hamilton Anxiety Scale (HAMA). Non-suicidal self injury will be assessed by the Adolescent Non-Suicidal Self-Injury Assessment Questionnaire (ANSAQ). Suicidal ideation and behaviors assessments will be measured with Beck Suicidal Scale Inventory (BSI). Changes in somatic symptom severity from baseline to the end of the study will be measured with the Patient Health Questionnaire-15 (PHQ-15). Sleep quality and disturbances will be assessed by the Pittsburgh Sleep Quality Index (PSQI). Insomnia severity will be evaluated using the Insomnia Severity Index (ISI). Ruminative thinking styles will be measured with the Ruminative Responses Scale (RRS). Impulsivity and aggression assessments will be measured with the Barratt Impulsiveness Scale (BIS) and the Buss-Perry Aggression Questionnaire (BPAQ), respectively. Additionally, pain-related attention and hypervigilance will be assessed by the Pain Vigilance and Awareness Questionnaire (PVAQ). Adverse event record form (AERF) will be used to appraise the safety of TIS treatment. Changes of brain structure and brain activities will be acquired by pre and post-interventional magnetic resonance imaging (MRI).

Inclusion Criteria:

1. Meet the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders 5th Edition) diagnostic criteria for major depressive disorder.
2. Patients aged 12-22 years with at least one guardian to monitor them for 3 months
3. HAMD-17 Total score ≥18
4. Patients who had two or more non-suicidal self-injury behaviors meeting the 5.DSM-5 diagnostic criteria in the 2 weeks before admission (NSSI behavior of more than 5 days in the past year)

6.Obtain informed consent from patients and guardians

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Exclusion Criteria:

1. Substance abusers such as psychoactive drugs or alcohol.

2. Severe physical disability and unable to complete follow-up.

3. Comorbid other major mental illnesses that meet the DSM-5 criteria, such as bipolar disorder, schizophrenia, mental retardation, dementia, severe cognitive impairment, attention deficit hyperactivity disorder, etc.

4. Suffering from any severe physical disease, neurological disease, traumatic brain injury, etc, that affects the structure or function of the brain in the lifetime.

   Unable to read, understand and complete the assessment or to cooperate with the investigators.

5. Any implants covering a pacemaker, metallic or magnetic objects in the body, or other conditions not suitable for TIS.

6. Those who have received systematic psychotherapy (interpersonal relationship therapy, dynamic therapy, cognitive behavioral therapy) or TMS within 3 months before baseline.

7. Other examination abnormalities considered to be inappropriate by investigators.

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