Does TMS Work for Depression? What Clinicians Should Know

In this video overview, Andrew Van Der Vaart, MD, addresses the questions clinicians ask most often about transcranial magnetic stimulation (TMS) for major depressive disorder: whether it works, who it works for, and how it works. The short answer on efficacy is reassuring. Roughly two-thirds of patients (60 to 70 percent) respond to TMS, meaning at least a 50 percent reduction in depression symptom severity on self-report measures like the PHQ-9 or clinician-rated scales like the MADRS. About half of those responders reach full remission. Those proportions are borne out by large real-world data, including the NeuroStar Outcomes Registry of more than 17,000 patients, which shows a 69 percent response rate on self-report scales.

The harder question is who responds. The field still lacks reproducible predictors of which patients fall into the responding two-thirds, though med history, inflammatory markers, or the character of the depression (agitated versus anhedonic) may eventually help. In Dr. Van Der Vaart’s clinical experience, TMS pairs especially well with moderate-to-severe, insidious depression marked by a lack of activation energy, the kind of presentation where a therapist would reach for behavioral activation. Practical fit matters too: patients need the stability to attend sessions Monday through Friday for about six weeks. The main contraindication is ferromagnetic hardware above the neck, with added caution around anything that lowers seizure threshold (high-dose bupropion, tramadol, clozapine). Cognitive side effects are essentially nil, a real advantage over ECT, and the most common complaint is transient scalp discomfort. Most commercial payers and Medicare cover TMS for treatment-resistant depression, typically requiring documentation of two or more treatment failures in the current episode.

On mechanism, TMS uses a pulsing electromagnetic field to induce an electric field in the cortex and depolarize neurons. Depression appears to involve a retreat of activity from the lateral, task-positive networks toward the midline default mode network, where rumination becomes fixed; stimulating the dorsolateral prefrontal cortex aims to pull activity back laterally. Three protocols matter clinically. Standard 10 Hz repetitive TMS was the first FDA-approved approach, with sessions of at least 20 minutes. Intermittent theta-burst stimulation (iTBS) delivers 50 Hz bursts nested within a 5 Hz rhythm in just a few minutes per session and is non-inferior to 10 Hz. Both run a course of roughly 30 to 35 treatments over six weeks. The SAINT protocol (Stanford Accelerated Intelligent Neuromodulation Treatment), developed by the late Nolan Williams, MD, compresses treatment into 10 sessions a day for five days using the principle of spaced learning, and adds fMRI-guided precision targeting of the node most anti-correlated with the anterior cingulate. Its intensity suits acute, severe cases, but the fMRI requirement currently restricts it to a handful of specialty centers, and whether that degree of targeting is necessary remains an open question.