2026 ECNP Congress

PS04-4067

Neuropsychological and clinical outcomes of transcranial direct current stimulation in patients with anorexia nervosa: a randomized double-blind sham-controlled trial

Paweł Szewczyk — N. Kajka, J. Róg, R. Zuzanna, P. Krukow, M. Hordejuk, H. Karakuła-Juchnowicz, A. Makarewicz, K. Kister · University Clinical Hospital No. 1 in Lublin, I Department of Psychiatry- Psychotherapy and Early Intervention, Lublin, Poland

2026 ECNP Congress

Background

Anorexia nervosa is associated with impairments in cognitive control, cognitive flexibility, attentional processing, and body-related cognition, which have been linked to dysfunction of dorsolateral prefrontal networks. Transcranial direct current stimulation has been proposed as a potential adjunctive intervention for anorexia nervosa; however, current evidence remains limited and heterogeneous across clinical and neuropsychological outcomes. We hypothesized that active stimulation over the dorsolateral prefrontal cortex would produce greater improvement in neuropsychological functioning and body-related outcomes than sham stimulation. AIM: To evaluate whether active transcranial direct current stimulation over the dorsolateral prefrontal cortex provides greater improvement than sham stimulation in neuropsychological functioning, body-related cognition, obsessive-compulsive symptoms, and rumination in hospitalized patients with anorexia nervosa. METHODS: Forty-five female inpatients with anorexia nervosa were randomized to active stimulation (n=23) or sham stimulation (n=22) in a randomized, double-blind, sham-controlled trial registered at ClinicalTrials.gov (NCT05814458). Stimulation was delivered at 2 mA twice daily on weekdays for three weeks, resulting in 30 sessions, and targeted the dorsolateral prefrontal cortex. Outcomes included selective attention, processing speed, cognitive flexibility, verbal fluency, visuospatial organization and memory, body-related cognition, obsessive-compulsive symptoms, and rumination. Repeated-measures general linear models assessed time, group, and time-by-group effects. Delta scores were additionally compared using appropriate parametric or non-parametric tests. Baseline comparability between groups was verified before outcome analyses to reduce the risk that post-treatment differences reflected pre-existing cognitive or clinical imbalance. Because the sample was modest and several outcomes were exploratory, results were interpreted primarily through time-by-group interactions rather than isolated within-group changes. This approach was intended to distinguish a specific stimulation effect from general improvement during inpatient treatment, nutritional rehabilitation, clinical stabilization, or repeated neuropsychological testing. RESULTS: Significant improvements over time were observed across both groups in selective attention, processing speed, cognitive flexibility, verbal fluency, and body-related cognition (all p<0.01), indicating post-treatment improvement in the total sample. However, no significant time-by-group interaction was found for any analysed outcome, indicating no additional benefit of active stimulation over sham stimulation. Trend-level interaction effects were observed for visuospatial organization (p=0.058), obsessive-compulsive symptoms (p=0.067), and rumination (p=0.087). These effects did not provide consistent evidence of superiority of active stimulation. The interpretation therefore emphasizes effect specificity, direction of change, and consistency across neuropsychological, body-related, and clinical measures, rather than statistical significance alone. CONCLUSIONS: Active transcranial direct current stimulation over the dorsolateral prefrontal cortex did not confer additional benefit beyond sham stimulation in this neuropsychological analysis of anorexia nervosa. Observed improvements likely reflected non-specific effects of inpatient treatment, nutritional rehabilitation, repeated testing, or clinical stabilization. These findings suggest that short-term prefrontal neuromodulation may have limited impact on cognitive and behavioral domains in anorexia nervosa and challenge the assumption that modulation of prefrontal circuits translates into clear measurable clinical or neuropsychological benefit.

References

  1. Stedal, K., Broomfield, C., Hay, P., Touyz, S., Scherer, R., 2021. Neuropsychological functioning in adult anorexia nervosa: a meta-analysis. Neurosci. Biobehav. Rev. 130, 214-226. https://doi.org/10.1016/j.neubiorev.2021.08.021.
  2. Rząd, Z., Rog, J., Kajka, N., Szewczyk, P., Krukow, P., Karakuła-Juchnowicz, H., 2024. The efficacy of transcranial direct current stimulation in the treatment of anorexia nervosa: a randomized double-blind clinical trial. Front. Psychiatry 15, 1284675. https://doi.org/10.3389/fpsyt.2024.1284675.