Exploring the Impact of Frontal Transcranial Direct Current Stimulation on Self-Harm Behavior in Adolescents

INTERVENTION: Group 1: Adolescents aged 11 to 17 years with self‐harm behavior and a diagnosis of a depressive or anxiety disorder will receive anodal transcranial direct current stimulation (tDCS) targeting either the right dorsolateral prefrontal corte X(DLPFC) or the right inferior frontal gyrus (rIFG), depending on randomization. Stimulation will be delivered at an intensity of 2 mA for 20 minutes per session. Participants will receive a total of three stimulation sessions. Clinical, behavioral, and physiological assessments will be conducted before and after the intervention according to the study protocol. Group 2: Participants will receive sham stimulation (sham tDCS) using the same electrode placement and procedural schedule as the active condition. The stimulation will be briefly ramped up and down at the beginning of each session to mimic the sensory experience of active stimulation, without delivering a therapeutic dose of current. CONDITION: ; F32.0 Mild depressive episode PRIMARY OUTCOME: Frequency of self‐harm actions using a diary SECONDARY OUTCOME: * Perceived stress leading to the self‐harm behavior/mood/other individually defined psychiatric symptoms using symptom ; * Momentary assessments of heart rate and activity level using actigraphic devices with plethysmographic pulse registration (available in the Lab), ; * Questionnaire on self‐harming behavior (Fragebogen zum Selbstverletzenden Verhalten (SITBI‐G, German version)), ; * Quality of life using KIDSCREEN‐19 as well as expression of psychiatric symptoms of depression (BDI‐II) and anxiety (DISYPSIII‐Angst), ; * Adverse effects of stimulation using a standardized questionnaire, ; * Measurements of impulse control using in our Lab established and well validated paradigms such as Flanker test, Taylor aggression paradigm and emotional Stroop test, ; * Interviews with adolescents and their parents concerning ethical issues such as concerns INCLUSION CRITERIA: Adolescents aged 11 to 17 years • Willingness to participate in the experiment (informed consent from the patients and their legal guardians) • Normal intelligence quotient (IQ) > 80 • Diagnosis of depression and a history of self‐injurious behavior. ‐ Depression is assessed using the Beck Depression Inventory (BDI‐II)—a standardized depression questionnaire. ‐ Self‐injurious behavior is assessed using the SITBI‐G questionnaire (German version) and a self‐monitoring diary.