Efficacy and Safety of Transcranial Alternating Current Stimulation (tACS) Combined With Stable Medication in Adolescents With Depression

This randomized, double-blind, sham-controlled pilot study will evaluate the feasibility, acceptability, safety, and preliminary clinical effects of transcranial alternating current stimulation as an adjunctive treatment for adolescents with major depressive disorder. It will also examine changes in depressive symptoms and related clinical outcomes, while exploring potential effects on emotional regulation, cognitive function, and brain function following the intervention.

Inclusion Criteria: 1. Age 12-18 years. 2. Meet DSM-5 diagnostic criteria for a current depressive episode, as confirmed by the K-SADS-PL. 3. Children's Depression Rating Scale-Revised (CDRS-R) score ≥40 at baseline. 4. Stable psychotropic medication treatment for at least 4 weeks prior to enrollment and willingness to continue the same regimen throughout the study. Exclusion Criteria: 1. Psychiatric comorbidities other than anxiety disorders. 2. Depression with psychotic features. 3. Young Mania Rating Scale (YMRS) score \>13. 4. History of neurological disorders (e.g., epilepsy, traumatic brain injury) or severe physical illnesses (e.g., thyroid disease, lupus, diabetes, significant liver, kidney, or lung impairment, major trauma). 5. Previous treatment with electroconvulsive therapy (ECT), transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), tACS, or other neurostimulation therapies. 6. Current use of antiepileptic drugs or high-dose benzodiazepines. 7. History of alcohol or substance abuse or dependence. 8. Pregnant or breastfeeding females. 9. Contraindications to MRI. 10. Current high suicide risk.