Session Spotlight: Transcranial Magnetic Stimulation Today

Transcranial magnetic stimulation (TMS) today has advanced in precision and possible applications, psychiatrists said during an Annual Meeting session on “Targeted Healing: The Role of the Prescribing Doctor in TMS Therapy—Where, When, and How It Works.”

“It’s not your grandmother’s TMS,” said Shan Siddiqui, M.D., assistant professor of psychiatry at Harvard Medical School and director of psychiatric neuromodulation research at the Brigham and Women’s Hospital Center for Brain Circuity Therapeutics. “TMS is getting smarter.”

Siddiqui and Martijn Figee, M.D., Ph.D., professor of psychiatry and neurosurgery at Icahn School of Medicine at Mount Sinai’s Nash Family Center for Advanced Circuit Therapeutics, outlined how TMS works and its approved applications, and discussed recent advances and promising possibilities for neuromodulation.

One especially promising development is the use of functional magnetic resonance imaging to “personalize” the use of TMS by better targeting the treatment to brain regions associated with a specific patient’s specific symptoms.

Figee said currently most insurance doesn’t pay for a scan. “But if you use functional image–based targeting, you can see a more symptom-specific improvement.”

Another evolution is accelerated TMS combined with functional imaging. The SAINT Neuromodulation System for the treatment of refractory depression in adults, approved by the FDA in 2022, combines MRI-guided selection of the targeted brain region with an accelerated stimulation regimen involving multiple short TMS sessions every day for five days.

SAINT’s five-day protocol might expand options for patients who are hospitalized and/or present to the emergency room, as well as outpatients unable to commit to a six-week treatment regimen. “That is ideal—to have as many pulses as possible in just five days rather than spread out over six or seven weeks,” Figee said. “You can get your patient back on their feet because it works so quickly, with improvement in the first few days. With repeated neuromodulation you can create lasting neuroplastic changes in the brain.”

TMS is effective and safe in around 50% of patients with major depressive disorder (MDD) or obsessive-compulsive disorder (OCD) who have not responded sufficiently to psychotherapy or medication. In contrast to conventional treatments, TMS allows for direct and adjustable modulation of dysregulated brain circuits involved in psychiatric symptoms.

TMS of the dorsolateral prefrontal cortex modulates brain networks underlying negative mood in MDD, while TMS of the medial prefrontal or orbitofrontal cortex influences networks involved in reward processing and behavioral flexibility relevant for OCD.

Siddiqui noted that “TMS is not a ‘treatment’—it’s a tool that’s used to deliver treatment,” with different TMS targets and protocols approved for different conditions: major depressive episodes (since 2008), migraine with aura (since 2013), OCD (since 2018), and nicotine use disorder (since August 2020).

High-frequency (10 to 20 Hz) TMS is the conventional protocol with strongest evidence, while intermittent theta burst (iTBS), a form of repetitive stimulation, may be more efficient. One Hz is sometimes used in patients with high seizure risk.

Siddiqui added that TMS should not be regarded as “ECT lite.” It has a targeted mechanism of action, whereas ECT is more diffuse. “TMS is usually more tolerable and logistically feasible,” he said. “If I were admitted to your inpatient unit severely suicidal, give me ECT. But in any other circumstance, ECT is quite disruptive.” ■

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