Transcranial Direct Current Stimulation in Anorexia Nervosa: A Randomized Sham-Controlled Trial

Background/Objectives: Anorexia nervosa (AN) remains difficult to treat, and evidence for biological adjunctive interventions is limited. This study assessed the effectiveness of transcranial direct current stimulation (tDCS) as an adjunctive intervention in hospitalized patients with AN. Methods: In this double-blind, randomized, sham-controlled trial, 40 female inpatients with AN were allocated 1:1 to active tDCS or sham stimulation. Participants received 30 sessions over 3 weeks (2 mA, 25 min, twice daily on weekdays; anode F3, cathode F4), alongside standard inpatient treatment. Assessments were performed at baseline, post-intervention, and 2-week follow-up. Outcomes included eating disorder (ED) symptoms (EAT-26), depressive symptoms (BDI), perceived stress (PSS-10), self-esteem (SES), body mass index (BMI), and selected biological markers. Results: EAT-26 scores improved significantly from baseline to post-intervention in both groups; at the 2-week follow-up, scores remained significantly lower than baseline only in the active tDCS group. BMI and leptin increased significantly in both groups, while NT-3 decreased only in the active group. In multivariate analyses, higher leptin levels and greater perceived stress, adjusted for longer illness duration, were associated with greater improvement in ED symptoms; perceived stress predicted symptom improvement only in the active group. Conclusions: Active tDCS did not produce significantly greater short-term symptom reduction than sham in hospitalized patients with AN. However, findings observed at the 2-week follow-up and associations involving stress-related and metabolic measures require confirmation in studies with longer follow-up periods.