Background/Objectives: Anorexia nervosa (AN) is a severe disorder with limited treatment efficacy. This interim analysis aimed to assess the preliminary efficacy and safety of transcranial direct current stimulation (tDCS) in reducing core AN symptoms, stress, depression, low self-esteem, and BMI in adolescent females, to determine the rationale for continuing the study. Methods: A single-center, randomized, double-blind, placebo-controlled trial included 20 adolescent females with AN assigned to an active tDCS group (n = 10) or a sham group (n = 10). The intervention involved 30 sessions over three weeks, targeting the dorsolateral prefrontal cortex. Outcomes were assessed at baseline, post-treatment, and follow-up using the Eating Attitudes Test (EAT-26) for eating disorder symptoms, the Perceived Stress Scale (PSS-10) for stress, the Beck Depression Inventory (BDI) for depression, the Rosenberg Self-Esteem Scale (SES) for self-esteem, and body mass index (BMI) measurements. Safety and tolerability were assessed using the tDCS Side Effects Questionnaire. Results: Eating disorder symptoms significantly decreased in the active tDCS group at study end (p = 0.003) and follow-up (p = 0.02), while no significant changes were observed in the sham group. Although BMI increased more in the active group (13.78%) than in the sham group (7.31%), this difference was not statistically significant (p = 0.10). Conclusions: Adverse effects were mild and transient, with no serious safety concerns reported. Based on the results of this interim analysis, the study will proceed due to promising efficacy outcomes and good treatment tolerability.
Keywords: EAT-26; anorexia nervosa; brain stimulation; eating disorders; neuromodulation; tDCS; transcranial direct current stimulation.