NCT07474974

ipRGC as a Potential Biomarker for Predicting Transcranial Magnetic Stimulation Treatment Response in Major Depressive Disorder

Illuminating Depression: ipRGC as a Potential Biomarker for Predicting Transcranial Magnetic Stimulation Treatment Response in Major Depressive Disorder

• Status: Not Yet Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 44 (estimated)
• Sponsor: Polytechnic Institute of Porto · Academic / Other
• Sex: All
• Age: 18 Years – 65 Years
• Healthy volunteers: Not accepted

Summary

This research explores the potential of retinal ganglion cells (RGCs), particularly intrinsically photosensitive RGCs (ipRGCs), as biomarkers for predicting response to transcranial magnetic stimulation (TMS) in treatment-resistant depression (TRD). We also aim to assess the impact of TMS treatment on RGCs and ipRGCs in TRD patients, investigating associations with clinical improvements and cognitive status. A clinical trial involving 44 patients with treatment-resistant depression (TRD) will be conducted. All participants will receive rTMS targeting the dorsolateral prefrontal cortex (DLPFC). Data will be collected pre- and post-intervention, as well as at a 2-month follow-up, using multiple outcome measures, including the post-illumination pupil response (PIPR). The project seeks to confirm the effectiveness of TMS and the potential of RGCs/ipRGCs as predictors of treatment response, thereby facilitating the development of personalized treatment strategies for TRD patients undergoing rTMS therapy.

Conditions

• Depression - Major Depressive Disorder
• Treatment Resistant Depression

Interventions

Type	Name	Description
DEVICE	Repetitive transcranial magnetic stimulation (rTMS)	Each participant's resting motor threshold (RMT) will be determined by visual observation in accordance with standard clinical practice. Intermittent theta-burst stimulation (iTBS) will be delivered over the left dorsolateral prefrontal cortex (DLPFC) using these parameters: stimulation intensity 120% RMT; bursts at 50 Hz; 2 s on and 8 s off; 600 pulses per session; total stimulation time approximately 3 minutes per session. Stimulation will be delivered using a MagPro X100 stimulator with MagOption, equipped with a B70 butterfly-shaped coil with static cooling (MagVenture, Denmark). Treatment will comprise 20 sessions, delivered once daily on weekdays.

Timeline

• Start date: 2026-03-15
• Primary completion: 2027-04-30
• Completion: 2027-07-31
• First posted: 2026-03-16
• Last updated: 2026-03-16