TMS for depression

How TMS works

A magnetic coil placed against the scalp delivers brief magnetic pulses that pass through the skull and induce small electrical currents in cortical tissue. The pulses are targeted at the left dorsolateral prefrontal cortex (DLPFC), an area that is consistently underactive in depression and connected through circuits to the limbic system.

Repeated stimulation over weeks appears to strengthen activity in the targeted region and rebalance broader networks involved in mood regulation. The mechanism is not fully understood. The clinical effect is well established.

What a course looks like

Standard rTMS: 36 sessions over 6 weeks (5 sessions a week for 4 weeks, then a taper). Each session is 18 to 40 minutes depending on the protocol. The patient sits awake in a chair. There is no anesthesia, no recovery time, and no driving restriction. People can return to work or school the same day.

Theta-burst stimulation (iTBS): a shorter form of TMS, FDA-cleared in 2018, with sessions lasting about 3 minutes. A standard iTBS course is 36 sessions over 6 weeks, the same total course length as standard rTMS but each session is much shorter.

Accelerated TMS and SAINT: protocols delivering multiple iTBS sessions per day over 5 to 10 days. The Stanford SAINT trial (Cole, Am J Psychiatry 2022) reported a remission rate of 79 percent in treatment-resistant depression with a 5-day, 10-sessions-per-day protocol. Accelerated and SAINT-style protocols are now FDA cleared and increasingly available.

Who is a candidate

The standard FDA indication is major depressive disorder in adults who have failed at least one antidepressant trial of adequate dose and duration in the current episode. Insurance coverage typically requires documented failure of two or more antidepressants and an evidence-based psychotherapy attempt.

TMS is also FDA cleared for OCD, smoking cessation, anxious depression, and migraine. Adolescents (15 and older) have an FDA clearance specifically for the NeuroStar device.

Who should not have TMS

• People with non-removable ferromagnetic metal in the head (some aneurysm clips, cochlear implants, deep brain stimulators).
• People with implanted medical devices that are sensitive to magnetic fields (some pacemakers, depending on placement).
• People with a history of seizures or active risk of seizures (epilepsy, recent severe head injury, current high-dose stimulant or bupropion use, withdrawal states). Bupropion at standard doses is not an absolute contraindication; the prescriber and TMS team weigh the risk.
• People with bipolar disorder need careful evaluation. TMS can work in bipolar depression but mood elevation has been reported.

Pregnancy is not a contraindication; TMS does not expose the fetus to electrical or pharmacologic agents.

Evidence and response rates

Pooled data from clinical trials and large naturalistic registries (Carpenter, J Clin Psychiatry 2012; Sackeim, J Affect Disord 2020) show roughly:

• Response rate (50 percent or greater symptom reduction): 45 to 60 percent.
• Remission rate (full or near-full resolution of symptoms): 30 to 40 percent.
• The numbers are higher in less treatment-resistant patients and lower in patients who have failed many antidepressants.
• SAINT-style accelerated protocols have reported higher remission rates in initial trials, though longer-term data are still accumulating.

Durability: about half of patients who respond to a course of TMS remain well at 6 to 12 months. Maintenance protocols (a session weekly or every two weeks for several months) and re-introduction of TMS for relapse are both options.

Side effects

TMS is well tolerated. The most common side effects are scalp discomfort or headache during and after the session, both usually mild and improving over the first week. The most serious adverse event is seizure, which is rare (roughly 1 in 30,000 sessions in modern protocols) and almost always occurs within minutes of stimulation.

Unlike ECT, TMS does not cause memory loss, does not require anesthesia, and does not interfere with cognition.

TMS versus ECT versus ketamine

For treatment-resistant depression, three procedural treatments come up most often.

• TMS is the least invasive. No anesthesia, no cognitive side effects, can drive home. Lower remission rates than ECT in severe depression. Best for moderate to severe depression after one or two failed antidepressants.
• ECT is the most effective treatment in severe and life-threatening depression, with remission rates of 60 to 80 percent in psychotic, suicidal, or catatonic depression. Requires anesthesia, time off work, and carries short-term cognitive side effects. Best for the most severe cases.
• Ketamine and esketamine work fastest, often within hours to days. Useful when rapid relief is needed, including for acute suicidality. Effects are not as durable as ECT or a full course of TMS, so maintenance dosing is the norm.

The choice depends on severity, urgency, prior treatments, comorbidities, and availability.

Insurance and cost

Standard rTMS is covered by Medicare and most commercial insurers in the United States for major depressive disorder after documented failure of two or more antidepressants in the current episode. Theta-burst stimulation is also typically covered. Accelerated and SAINT-style protocols are newer and coverage is variable. Self-pay costs for a full course range roughly from $6,000 to $15,000 depending on the protocol and region.