The investigators aim to explore the efficacy and safety of rTMS therapies with different intervals between sessions for treating patients with moderate to severe depression.

FDA-approved intermittent theta burst stimulation (iTBS) for the treatment of depression disorder, reduces the duration of a single sequence treatment from 37 minutes to 3 minutes with traditional rTMS and gets the same antidepressant effect. Studies have shown that large doses and individualized target stimulation based on iTBS can improve the efficacy of rTMS and greatly save the time spent during patient treatment, but the effect of the interval between iTBS sessions on the efficacy is inconclusive. Previous studies on interval effect in rats based on iTBS have indirectly found that the waiting time between iTBS sessions of 50 to 90 minutes can maximize the cumulative effect of stimulation, so researchers mostly set the iTBS treatment interval to 50 minutes. However, most patients give up treatment because of the long wait time of 50 minutes, so it is urgent to explore the effect of short intervals of iTBS accepted easier by patients. In this study, we examined the intersession interval of 50 min vs. 20 min in the efficacy and safety of pBFS-guided TMS treatment in patients with moderate to severe depression.

After being informed about the study and potential risks. All patients giving written informed consent will undergo a screening period to determine eligibility for study entry. At week 0, patients who meet the eligibility requirements will be randomized in a double-blind manner in a 4:4:1:1 ratio to a 50-minute active rTMS group, a 20-minute active rTMS group, a 50-minute sham-control group, and a 20-minute sham-control group. And then all participants will undergo a 21-day rTMS treatment followed by two-week and four-week follow-up visits.

Inclusion Criteria:

• Meet the diagnostic criteria of DSM-5(Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition) for the depression disorder without psychotic symptoms, and currently experiencing recurrence episodes.
• Hospitalized patients aged 18-65 years (inclusive), male or female.
• Total HAMD-17 score ≥20 before randomization.Total MADRS score ≥25 before randomization.
• Inadequate response to at least one antidepressant trial of adequate doses and duration.
• A stable antidepressant regimen for at least 4 weeks at a dose not lower than the prescribed range of drug use before randomization.
• Voluntarily participate in the trial and sign informed consent.

Exclusion Criteria:

• Meet diagnostic criteria for other mental disorders (such as schizophrenia, schizoaffective disorder, bipolar disorder, secondary depression, and so on);
• Patients with a cardiac pacemaker, cochlear implant, or other metal foreign body and any electronic equipment implanted in the body, patients with claustrophobia and other contraindications to magnetic resonance scanning, and patients with contraindications to rTMS treatment;
• History of epilepsy (presence of at least 2 uninduced seizures more than 24 hours apart, or diagnosis of the epileptic syndrome, or seizures within the past 12 months); Or currently received medications or other treatments that will lower the seizure threshold;
• History of ECT, rTMS, and light therapy within 3 months;
• Patients with organic brain diseases (such as ischemic stroke, cerebral hemorrhage, brain tumor, etc.) and a history of severe brain trauma as judged by the researcher;
• Patients with serious heart, liver, kidney diseases, diabetes, and other serious physical diseases, causing symptoms and signs of brain abnormalities, or body failure;
• The female of childbearing potential plans to become pregnant during the trial, and the female who is pregnant or breastfeeding.
• Alcohol abuse or drugs abuse in the past 1 year;
• First-degree relatives have bipolar affective disorder. There is a significant risk of suicide (MADRS item 10 ≥ 5).
• Difficulty or inability to engage in normal communication, understand or follow instructions, and cooperate with treatment and evaluators.
• Currently participating in clinical trials of other drugs or physical therapy (e.g. deep brain stimulation DBS, electroconvulsive therapy ECT, rTMS).
• Investigators think that was inappropriate to participate.