Comparing Outcomes of Theta Burst Stimulation in Depression Using Advanced PET Imaging

The proposed project will investigate the neurobiological mechanisms of accelerated intermittent Theta Burst Stimulation (iTBS) in major depressive disorder (MDD) using an advanced multimodal imaging approach. This single-arm, within-subject study will deliver one week of accelerated iTBS and use pre-/post-treatment PET/MRI to quantify changes in synaptic density, functional connectivity, and microstructural integrity. We will combine \[¹⁸F\]SynVesT-1 PET with functional, neurochemical and anatomical MRI, such as resting-state fMRI, magnetic resonance spectroscopy (MRS) and neurite orientation dispersion and density imaging (NODDI), to capture treatment-related plasticity. This integrated design will link molecular and network-level mechanisms to clinical improvement, providing an unprecedented mechanistic map of how accelerated iTBS restores brain function in depression.

NCT Number	NCT07620288
Lead Sponsor	The Royal Ottawa Mental Health Centre
Conditions	Depression, Depression - Major Depressive Disorder, Depressive Episode, Major Depressive Disorder (MDD)
Enrollment	20 participants
Start Date	2026-08-01
Primary Completion	2028-07-30 (estimated)
Study Completion	2028-07-30 (estimated)
Updated on ClinicalTrials.gov	2026-06-09