Intracranial Electric Field Dosage and Clinical Response to Electroconvulsive Therapy in Depressed Patients

Electroconvulsive therapy (ECT) provides rapid relief of depressive symptoms. However, the relationship between intracranial electric field (E-field) distribution, dosage, and antidepressant outcomes remains underexplored. Thirty patients with depressive episodes received bifrontal ECT. Clinical symptoms were assessed using the 17-Item Hamilton Rating Scale for Depression at baseline and post-ECT treatment. Magnetic resonance imaging was performed at baseline to calculate E-field strength and intracranial E-field dosage. No significant associations were found between accumulated or average E-field dosage and overall antidepressant outcomes. However, significant associations were observed between antidepressant outcomes and E-field dosage during the initial ECT session in key brain regions, including the amygdala, anterior cingulate cortex, cerebellum, hippocampus, medial para-hippocampal cortex, postcentral gyrus, thalamus, and superior frontal lobe (P all < 0.05). While no significant associations were found between cumulative or average E-field dosage and antidepressant outcomes of ECT, significant associations were observed between E-field dosage in key brain regions and antidepressant outcomes during the initial ECT session. These findings suggest that individualized ECT protocols, tailored to patient-specific neuroanatomy and E-field dosage in specific brain regions, may enhance ECT's therapeutic efficacy. Future research should explore personalized ECT protocols using computer-modeled E-field distribution and ECT parameters.