HD-tDCS for Adolescent Bipolar Depression Targeting S1

This study aims to evaluate the efficacy and underlying biological mechanisms of HD-tDCS targeting the primary somatosensory cortex (S1) in adolescents with bipolar depression. Participants will be randomly assigned (1:1) to receive either active HD-tDCS or sham stimulation for 10 consecutive days (twice daily, 20 minutes each session), in addition to standard clinical care. Multimodal assessments will be conducted at baseline, mid-treatment (after 10 sessions), and post-treatment, including clinical symptom scales, neurocognitive evaluations, structural and functional MRI, blood biomarkers (15ml of peripheral blood), as well as digital phenotyping data such as voice, EEG, PPG, sleep, and behavioral metrics. The study also aims to identify objective biomarkers predictive of treatment response and to elucidate the neurobiological mechanisms associated with HD-tDCS applied to the S1 region. All procedures including MRI, tDCS, and assessments are non-invasive and free of charge for participants. The total duration of data collection and follow-up is expected to span approximately two years.