We are faced with a decrease in rTMS activity at the study sites, as well as problems with the active file meeting the protocol inclusion criteria, resulting in a low recruitment rate and an extended study timetable, forcing us to suspend this study.

Changes in heart rate variability following a single session of rTMS will be tested as a predictor of response to a course of 30 rTMS sessions in patients with major depressive disorder (MDD).

The objective of this study is to investigate whether acute changes in heart rate variability following a single session of repetitive transcranial magnetic stimulation (rTMS) can predict the response to a 30-session course of rTMS in patients with major depressive disorder (MDD) with good sensitivity and specificity. Patients who are prescribed rTMS to treat an episode of MDD at one of the nine participating centres will be invited to participate in the study. The protocol includes one inclusion visit and seven evaluation visits before, during, and after the course of rTMS. The rTMS course will last for six weeks, comprising of 30 sessions with five sessions per week. Prior to the start of the rTMS course, the patient will have to fill in a number of questionnaires. Before the first session, heart rate variability will be assessed by recording the RR interval at rest using a heart rate belt on the armchair stimulation. A second RR interval recording will be taken immediately after the first rTMS session. Patients will answer questionnaires weekly and after the final rTMS session to track the progression of depressive symptoms.

Inclusion Criteria:

• Having a prescription for a course of rTMS to treat an episod of MDD
• Unipolar MDD confirmed according to DSM-5 criteria
• Moderate to severe MDD (MADRS score > 19)
• No use of psychotropic medication or use stabilised (no change in dose < 4 weeks before study entry)
• Able to understand, speak, read and write French
• Express informed consent, after a period of reflection
• Affiliated with a French social security scheme or beneficiary of such a scheme

Exclusion criteria:

• History of epilepsy or convulsive seizures
• Previous brain surgery
• History of recent cranial trauma (< 6 months)
• Presence of severe suicidal ideation
• Psychotic disorders
• Metal objects in the head, eyes or brain
• Implanted ferromagnetic equipment (pace maker, cochlear implant, etc.)
• Clinical evidence of serious or uncontrolled alcohol or substance use disorders in the three months prior to the study
• Active withdrawal from alcohol or other substances
• One or more recent rTMS sessions (< 4 weeks)
• Other non-drug therapy recently initiated (< 4 weeks) to treat MDD (psychotherapy, phototherapy, vagus nerve stimulation, etc.)
• Prescription of cardiotropic drugs belonging to the following classes: predominantly cardiac calcium channel blockers, Vaughan Williams class I anti-arrhythmics and beta-blockers.
• Subjects in a period of relative exclusion from another protocol
• Adults protected by law or patients under guardianship or curatorship
• Subjects deprived of their liberty by judicial or administrative decision
• Pregnant or breast-feeding women

Patients recruited will be patients who have been admitted as an outpatient for the treatment of MDD by rTMS treatment at one of the 9 study centres.