Rapid Antidepressant Dynamics in Acute Neuromodulation Treatments

The goal of this clinical trial is to learn how different types of non-invasive brain stimulation affect mood and brain function in adults with major depressive disorder (MDD). It will also study how brain stimulation may work together with antidepressant treatments. The main questions this study aims to answer are: How do different patterns of brain stimulation affect mood in people with depression? Do brain networks involved in emotion and self-reflection respond differently depending on the type of stimulation? What are the combined effects of brain stimulation and antidepressant treatments on mood and brain activity? Researchers will compare different brain stimulation patterns and target areas to understand their individual and combined effects. Participants will: Receive three types of brain stimulation (intermittent, continuous, and sham) in different sessions Undergo MRI scans during the administration of either a fast-acting or conventional antidepressant Complete mood assessments during the scan and for one week after each session This study may help identify brain-based strategies to improve treatment for depression.

This mechanistic clinical trial will investigate the role of large-scale brain networks in modulating mood responses in adults with major depressive disorder (MDD) using non-invasive neuromodulation and neuroimaging. The study will focus on the salience network (SN), default mode network (DMN), and functional connectivity (FC) between them, given prior evidence linking these systems to mood regulation and antidepressant response. Using a 2x3 factorial design, 200 participants with MDD will be randomized to receive theta burst stimulation (TBS) targeting either the SN or the DMN (between-subject factor). Each participant will complete three within-subject TBS sessions one week apart: intermittent TBS (iTBS), continuous TBS (cTBS), and sham stimulation. TBS will be delivered over individualized fMRI-based targets derived from prior resting-state connectivity maps. Following each stimulation session, participants will complete an MRI protocol that includes administration of either a fast-acting or conventional antidepressant, as well as resting-state functional imaging. Primary neural outcomes include changes in activation and connectivity within and between SN and DMN regions, measured using task-based and resting-state fMRI. Behavioral outcomes include mood ratings acquired repeatedly during the scanning session and via daily remote assessments for one week post-stimulation. This design allows for within-subject comparison of the acute and sub-acute effects of different TBS patterns, and between-subject comparison of SN- vs. DMN-targeted stimulation. The study aims to identify brain circuits that can be engaged or modulated to enhance treatment response in depression, with the longer-term goal of informing precision neuromodulation strategies. Note: Certain information is withheld to protect the scientific integrity of the study design.