Investigating depressive symptoms with non-invasive brain stimulation

The study uses non-invasive brain stimulation (TMS-EEG) and imaging techniques (MRI) to study how the brain changes during periods of high vs. low anxiety. The study requires 11 visits that include a clinical interview, screening questionnaires, MRI and 8 TMS-EEG sessions. During TMS-EEG, you be comfortably seated wearing a fitted sensor cap that will be gelled. A coil will be positioned over different areas of your brain and small pulses will be administered to record brain activity

Eligibility Criteria

You will be Included in the study if you are:

1. Age 18-65 years old;
2. Diagnosed with generalized anxiety disorder (GAD)
3. Do not abuse substance such as drugs or alcohol
4. Fluent in English
5. Voluntary and competent to consent;
6. Sign and date the informed consent form;
7. Stated willingness to comply with all study procedures.

1. Have a history of a medical or neurological disorder that affects the central nervous system (such as, traumatic brain injury, stroke, Parkinson);
2. Have a history of seizures;
3. Cannot or do not wish to receive a research MRI scan (e.g., due to metal implants or dentures that are incompatible with the scanner, or due to claustrophobia);
4. Have serious or unstable medical condition requiring immediate investigation or treatment;
5. Have cardiac pacemaker, cochlear implants, implanted electronic devices or non- electronic metallic implants or other contraindications to MRI;
6. Taking more than 2mg of lorazepam or equivalent benzodiazepine per day

What does the study involve?

• Number of contacts: 10+ in-person visits
• Compensation offered? Yes

Investigator(s): Dr. Christoph Zrenner 
Full Study Title: Identification of EEG and TMS-EEG Markers of Symptom Severity State in Anxiety 
(ANXMARK)

Contact Information:
E-mail: camhbrainstudy@camh.ca

REB number: 2023/107
REB Approval Expiry Date: October 17, 2025

PLEASE NOTE:

• Research staff cannot give medical advice over the phone or via email.
• If you have specific questions regarding your health care, please contact your family physician.
• We regret that not everyone screened for a study will be eligible to participate
• For more information about other treatment options for mental illness or addiction offered by CAMH, visit www.camh.ca or call 416-535-8501.