Exploring brain effects of a new depression treatment using theta burst stimulation

Neural Mechanisms of Intermittent Theta Burst Stimulation in the Core Depression Network

Not applicable Interventional The Royal Ottawa Mental Health Centre · NCT05224206

This study is testing a new brain treatment for major depression to see how it affects brain activity compared to a fake treatment.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment22 (estimated)
Ages18 Years to 55 Years
SexAll
SponsorThe Royal Ottawa Mental Health Centre Academic / other
Locations1 site (Ottawa, Ontario)
Trial IDNCT05224206 on ClinicalTrials.gov

What this trial studies

This clinical trial investigates the effects of intermittent theta burst stimulation (iTBS), a novel form of repetitive transcranial magnetic stimulation (rTMS), on individuals diagnosed with major depressive disorder (MDD). The study aims to compare the neuronal effects of iTBS to a sham treatment using advanced imaging techniques such as positron emission tomography (PET) and magnetic resonance imaging (MRI). Participants will undergo a double-blind cross-over experiment followed by a 6-week daily treatment course of iTBS to assess its efficacy and mechanisms of action. The goal is to enhance understanding of how iTBS modulates brain activity in the context of depression.

Who should consider this trial

Good fit: Ideal candidates for this study are men and women aged 18 to 55 with a confirmed diagnosis of major depressive disorder who have not responded to previous antidepressant treatments.

Not a fit: Patients with active substance abuse, psychotic features, or other significant mental health disorders may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could provide a rapid and effective option for patients suffering from major depressive disorder.

How similar studies have performed: While the use of rTMS has been established, the specific application of iTBS is relatively novel, and its effects are still being explored in clinical settings.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Men or women aged 18 to 55 years of age
* Mini-International Neuropsychiatric Interview-confirmed diagnosis of MDD, as a single or recurring episode
* Symptoms of MDD have not improved after ≥ 1 but ≤ 7 adequate dose(s) of antidepressant trial(s) in the current depressive episode
* A baseline score of ≥ 15 on the 17-item Hamilton Rating Scale for Depression (HRSD-17)
* Have received a stable antidepressant regimen for at least four weeks prior to entering trial
* Are voluntary and competent to consent to study
* Can speak and read English

Exclusion Criteria:

* 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
* Suicide attempt in the past three months and/or active suicidal intent
* Pregnancy (confirmed by urine test) and/or lactation
* Psychotic features in the current episode
* Any comorbid mental health disorders (including, but not limited to lifetime history of psychotic disorders, OCD, PTSD and/or bipolar I or II disorder) with the exception of anxiety/panic disorders and ADHD
* Significant unstable medical or neurologic illness confirmed by medical history and blood test at baseline (e.g. uncontrolled diabetes, or renal dysfunction)
* Organic cause to the depressive symptoms (e.g. thyroid dysfunctions), as ruled out by the referring physician
* Contraindication for TMS (e.g., personal history of epilepsy or convulsion, metallic head implant, pacemaker)
* Contraindication for MRI (e.g. metallic implant, claustrophobia)
* Have undergone a prior PET or SPECT research study
* ECT or rTMS treatment in the current depressive episode
* Benzodiazepine use
* Have a body mass index (BMI) higher then 35 or lower then 18
* Any other condition that, in the opinion of the investigators, would adversely affect the participant's ability to complete the study

Where this trial is running

Ottawa, Ontario

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Major Depressive DisorderiTBSrTMSpositron emission tomography
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.