Post Treatment Structural Correlates of Electroconvulsive Therapy in Patients with Treatment Resistant Depression
María Eugenia Samman1,2,3, Leticia Fiorentini1,4, Aki Tsuchiyagaito7, Elsa Costanzo4, Luis Ignacio Brusco10, Joan A. Camprodon6, Cecilia Forcato2, Salvador M. Guinjoan7,8,9, Mirta F. Villarreal1,3,5
Grupo de Investigación en Neurociencias Aplicadas a las Alteraciones de la Conducta (Grupo INAAC), Instituto de Neurociencias FLENI-CONICET, Buenos Aires, Argentina
Laboratorio de Sueño y Memoria, Departamento de Ciencias de la Vida, Instituto Tecnológico de Buenos Aires (ITBA), Buenos Aires, Argentina
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
Servicio de Psiquiatría, Fleni, Buenos Aires, Argentina
Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
Laureate Institute for Brain Research, Tulsa, Oklahoma, USA
Department of Psychiatry, Oklahoma University Health Sciences Center, Tulsa, Oklahoma, USA
Oxley College of Health Sciences, Tulsa University, Tulsa, Oklahoma, USA
Centro de Neuropsiquiatría y Neurología de la Conducta (CENECON), Facultad de Medicina, Universidad de Buenos Aires.
Presenting Author: María Eugenia Samman
mariaeugeniasamman@gmail.com
Electroconvulsive therapy (ECT) remains one of the most effective interventions for treatment-resistant depression (TRD). This study investigated whether cortico-limbic structural connectivity following ECT is associated with symptom severity and clinical response. Twenty-three patients with TRD underwent diffusion MRI after bifrontal ECT. Structural connectivity (SC) was estimated using probabilistic tractography between seven bilateral regions previously implicated in depressive symptomatology. Symptoms were assessed with the Hamilton Depression Rating Scale. After ECT, 18 connections were significantly associated with clinical response. Specifically, greater clinical improvement was linked to lower SC within a fronto-limbic network. When restricting the analysis to responders (change in Hamilton score higher than 50%), this association remained significant, with the right anterior insula emerging as a key hub. Interestingly, this pattern was already evident in the pre-treatment SC of the right anterior insula, where higher connectivity predicted poorer response. These findings suggest distinct structural biomarkers of treatment outcome and underscore the importance of anatomically precise neuromodulation strategies to enhance ECT efficacy while minimizing adverse effects in TRD.
