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

ClinicalTrials.gov IDNCT07474974

PhaseNA

Enrollment44

SponsorPolytechnic Institute of Porto

Age18 Years

SexALL

I'm interested View official listing

Conditions studied

Depression - Major Depressive Disorder, Treatment Resistant Depression

About this study

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.

Interventions

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.

Primary outcomes

Chromatic pupillometry (Baseline (pre-intervention), Post-intervention (a day immediately after the end of intervention) and Follow-up (2 months after the end of intervention))

Eligibility information

Inclusion Criteria: * Diagnosis of MDD, confirmed via the structured clinical interview; * TRD type; * Age between 18-65 years; * Visual acuity of 20/32 or better. Exclusion Criteria: * Prior rTMS treatment; * Contraindications for TMS; * Psychiatric disorders other than MDD; * Systemic diseases affecting the eyes (e.g., diabetes mellitus); * Ocular conditions; * Head injuries causing loss of consciousness; * Current or past alcohol/substance dependence within 6 months; * Neurodegenerative diseases; * Major neurological illnesses; * Use of medications affecting iris mechanics or the autonomic nervous system.

Study locations

RISE-Health, Center for Translational Health and Medical Biotechnology Research (TBIO), School of Health, Polytechnic of Porto, Porto, Porto District 4200-072 Portugal

Before you participate: Varda Clinical is an independent discovery tool, not the study sponsor or a medical provider. Eligibility can only be determined by the official study team. Discuss potential risks and benefits with a qualified healthcare professional.

Source: ClinicalTrials.gov. Record last refreshed by Varda Clinical: 2026-09-27.