Evaluating the Therapeutic Potential of Focal Electrically Administered Seizure Therapy (FEAST) in the Treatment of Depression: A Multicenter Randomized Clinical Trial

A significant proportion of patients remain resistant to antidepressant therapies, even when treatment is well managed. Electroconvulsive therapy (ECT) is a well-established method for treating certain severe and resistant psychiatric pathologies. ECT is also the gold standard for treating mood disorders. Although effective, it is associated with cognitive side effects (memory impairment, post-ECT confusion, longer reorientation time), particularly with bitemporal (BT) montage and brief pulse stimulation. These effects may contribute to patient reluctance and limit adherence to this therapy. From a mechanistic point of view, ECT causes changes in cerebral blood flow (rCBF) and brain electrical activity, particularly in the prefrontal cortex, where the induction of "pseudo-epileptic seizures" appears to be related to therapeutic efficacy, while cognitive side effects appear to be associated with alterations in the temporal areas. The conventional stimulation method results in widespread diffusion of the current due to the properties of the skull, limiting control over the distribution of intracerebral charge densities. In this context, a new approach called "Focal Electrically Administered Seizure Therapy" (FEAST) has been developed to focus the electrical current and limit cognitive side effects. Unlike traditional ECT, FEAST uses unidirectional current and optimized electrode placement, aiming to induce seizures in a more localized manner in the right prefrontal cortex while reducing propagation to temporal regions. The FEAST configuration is based on scientific literature (protocols, parameters, electrode positioning) and not on a "pre configured" mode validated by the medical device manufacturer. Neuroimaging studies suggest that FEAST causes an increase in blood flow in the right prefrontal cortex at the onset of the seizure, followed by a postictal redistribution similar to that observed with ECT, confirming its targeted effect. Open-label clinical trials conducted to date show that FEAST significantly improves depressive symptoms with a more favorable cognitive profile compared to traditional ECT, notably by reducing the impact on autobiographical memory and decreasing the time needed to regain orientation acutely after treatment. Several comparative studies between FEAST and unilateral ultra-brief pulse ECT suggest an advantage in terms of cognitive tolerance, although the differences are not always statistically significant. A multicenter trial also showed comparable effects on reducing suicidal ideation, suggesting that FEAST could be an alternative to traditional ECT. Indeed, preliminary studies indicate that FEAST may offer similar benefits to ECT in terms of reducing depressive symptoms, but with fewer cognitive side effects, which could lead to a better quality of life. Although these studies are promising, they remain few in number and have methodological limitations (open-label clinical trials, feasibility studies, lack of randomization with a comparator arm, small sample size, or assignment to the study arm based on patient preference). There are currently no other randomized clinical trials on FEAST underway or in preparation worldwide. Well-designed, multicenter clinical trials with sufficient patient numbers to achieve satisfactory statistical power are therefore needed to address the limitations of previous studies and explore the clinical benefits of FEAST. The present study is therefore a randomized, multicenter, double-blind clinical trial designed to evaluate the superiority of FEAST in terms of safety and efficacy compared to traditional ECT modalities.

Inclusion Criteria: * Age between 18 and 90 years; * Moderate-severe MDE as part of a unipolar or bipolar disorder (including psychotic and catatonic features) according to DSM-5-TR criteria (APA, 2022); * Score ≥ 17 at the HDRS-17 at the inclusion interview (HAMILTON, 1960); * Ability to understand the clinical investigation plan and comply with study visits; * ECT indicated by the referring physician for MDE; * Ability to tolerate the necessary adaptations to certain treatments (discontinuation, dosage, frequency of intake) for the proper conduct of ECT/FEAST (lithium, anticonvulsants with the exception of lamotrigine) and the restriction of benzodiazepine dosage to ≤ 3 mg/day of lorazepam equivalent (Boylan et al., 2000, Nahas et al., 2013, Sahlem et al., 2020, Youssef et al., 2021); * Written informed consent. Exclusion Criteria: * Previous diagnosis of neurologic disease: neurodegenerative disease, epilepsy, encephalopathy, delirium tremens or memory disorder, …; * Score \< 23 on the MoCA at inclusion interview (Nasreddine et al., 2005); * Other neurological diseases affecting the central nervous system or head trauma in progress or having had a cognitive impact according to the anamnesis and the clinician's assessment. This include: space-occupying cerebral lesions, such as tumors or hematomas, cerebrovascular aneurysms or malformations, recent stroke (hemorrhagic or ischemic), other causes of increased intracranial pressure (e.g., hydrocephalus, meningitis, encephalitis), skull defects (which may include metal devices in or near the site of stimulation), metal devices, such as screws and plates or metal meshes, may preclude specific stimulation patterns but may not preclude treatment administration completely, implanted active stimulatory devices (e.g., Deep Brain Stimulation devices). Stimulation devices may pose a risk to the patient if the flow of current during treatment damages active components of the device (i.e. potential for catastrophic failure of the battery); * General condition and/or comorbidities not allowing general anesthesia to be performed; * Severe and unstable pulmonary conditions increasing the risks of problematic airway management and aspiration during and immediately after ECT according to the anesthesiologist's assessment such as chronic obstructive pulmonary disease (COPD), asthma, pneumonia; * Severe and unstable cardiovascular conditions substantially increasing risks according to the anesthesiologist's assessment, such as recent and/or severe myocardial infarction, unstable angina, uncompensated congestive heart failure, vascular aneurysm or stenosis, clinically significant arrhythmias, uncontrolled hypertension or hypotension; * Concomitant psychotic disorder (schizophrenia, schizoaffective disorder) according to DSM-5-TR or than MED with psychotic features (APA, 2022); * Moderate to severe substance use disorder in the 3 months preceding the inclusion in the study (except caffeine and nicotine) (G. L. Sahlem et al., 2016, Youssef et al., 2021); * Rapid-cycling bipolar disorder (Youssef et al., 2021); * Having received an acute course of ECT in the 3 months preceding the inclusion in the study; * Participation in another interventional research protocol other than magnetic resonance imaging (MRI) studies); * Patient deprived of their liberty by judicial or administrative decision; * Patient under legal protection; * Pregnant and breastfeeding women; * Patient not affiliated to a social security or other social protection scheme.