Comparing Outcomes of Theta Burst Stimulation in Depression Using Advanced PET Imaging (NCT07620288) | Clinical Trial Compass
Not Yet RecruitingNot Applicable
Comparing Outcomes of Theta Burst Stimulation in Depression Using Advanced PET Imaging
Canada20 participantsStarted 2026-08-01
Plain-language summary
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.
Who can participate
Age range
18 Years – 55 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion criteria
. 18 to 55 years old.
. Competent to provide voluntary informed consent.
. English comprehension and verbal communication (participants must be able to both understand and speak English sufficiently to follow study procedures and be understood by study personnel
. Referred by their treating physician.
. Mini-International Neuropsychiatric Interview-confirmed diagnosis of MDD, as a single or recurring episode.
. Symptoms of MDD have not improved after ≥ 1 adequate antidepressant medication trial in the current depressive episode29.
. Baseline score of ≥18 on the 17-item Hamilton Rating Scale for Depression (HRSD-17).
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1This trial uses PET scans with a radioactive tracer called [¹⁸F]SynVesT-1 to measure changes in synaptic density in the brain — can you explain what that means for my safety and how many PET scans I'd likely need to undergo?
2The trial is listed as 'not yet recruiting,' so is there any realistic timeline for when it might open, and would waiting to potentially join it delay other depression treatments I could start now?
3Since this study doesn't have a traditional phase number, it seems focused on understanding how theta burst stimulation works in the brain rather than proving it's better than existing treatments — does that mean I shouldn't expect it to be a primary treatment option for me?
4Theta burst stimulation is a form of TMS (transcranial magnetic stimulation) — given my specific situation with depression, is TMS already considered a standard option for me, and how does participating in a research study like this compare to just pursuing it outside of a trial?
5What would the full commitment look like in terms of time, travel, and procedures if this trial does open and I were to discuss enrollment with you — especially given the PET imaging component?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Change in Synaptic Density Following iTBS Measured by [¹⁸F]SynVesT-1 PET
Timeframe: Administered at baseline (prior to first iTBS treatment), and after the iTBS treatment course (i.e. one week later).
. Maintained a stable treatment regimen for at least four weeks prior to entering the study, defined as being on a stable antidepressant regimen, a stable psychotherapy regimen, both, or neither (i.e., no treatment), with no changes during this period.
Exclusion criteria
. Any comorbid mental health disorders (including, but not limited to lifetime history of psychotic disorders, OCD, and/or bipolar I or II disorder) with the exception of anxiety/panic disorders, posttraumatic stress disorder and ADHD
. Current or past (\< 3 months) substance (including nicotine) or alcohol abuse/dependence, as defined in DSM-5 criteria.
. Positive urine test for illegal substances, cannabis, or cotinine.
. Significant unstable medical or neurologic illness confirmed by medical history (e.g. uncontrolled diabetes, or renal dysfunction).
. Breastfeeding or pregnant (confirmed via urine test).
. BMI \> 30 or BMI \< 18.
. Contraindication for TMS (e.g., personal history of epilepsy or convulsion, metallic head implant, pacemaker).
. Contraindication for MRI (e.g. metallic implant, claustrophobia).