Transcranial magnetic stimulation (TMS) is a noninvasive brain stimulation treatment for depression that uses magnetic pulses to activate nerve cells in areas of the brain linked to mood regulation. It’s primarily used for people whose depression hasn’t improved with antidepressant medication, and a standard course involves daily sessions over about six weeks. Unlike electroconvulsive therapy (ECT), TMS doesn’t require anesthesia, and you stay fully awake during the procedure.
How TMS Works
During a TMS session, an electromagnetic coil is placed against your scalp near your forehead. The coil delivers brief magnetic pulses that pass through the skull and stimulate nerve cells in the prefrontal cortex, a region involved in mood and emotional regulation. In people with depression, this area often shows reduced activity. The magnetic pulses essentially “wake up” these underactive circuits, encouraging them to fire more normally.
The most common approach targets the left dorsolateral prefrontal cortex with high-frequency pulses, which increases neural activity. A less common method delivers low-frequency pulses to the right side of the same region, which has a calming effect. Both approaches produce similar clinical outcomes, though high-frequency stimulation to the left side has been studied more extensively.
What a Treatment Course Looks Like
A standard TMS treatment plan involves 5 sessions per week for about 6 weeks, totaling 30 to 36 sessions. Each session lasts between 20 and 40 minutes depending on the specific protocol and device. You sit in a chair, similar to a dentist’s office, while the coil delivers pulses. There’s no sedation, no recovery time, and most people drive themselves to and from appointments.
During the first session, your provider maps the correct position on your scalp and calibrates the intensity of the magnetic pulses to your individual threshold. You’ll hear clicking sounds and feel a tapping sensation on your forehead. Some people find this uncomfortable at first, but most adjust within the first few sessions.
How Effective TMS Is
In clinical studies, roughly 40 to 45% of people with major depression respond meaningfully to TMS, meaning their symptoms drop by at least half. Full remission, where symptoms essentially resolve, occurs in about 16 to 22% of patients. These numbers may sound modest, but keep in mind that TMS is typically offered to people who have already tried and failed antidepressant medications, a group that is inherently harder to treat.
A newer accelerated protocol developed at Stanford has shown dramatically higher response rates in early trials. Instead of spreading treatment across six weeks, this approach delivers 10 sessions per day over 5 consecutive days. In an initial study of 22 participants with treatment-resistant depression, 90% responded and about 86% achieved full remission. On average, participants began responding after just over two days of treatment. One month later, 70% still met response criteria. This protocol is newer and less widely available, but it represents a significant shift in how quickly TMS can work.
Common Side Effects
TMS has a mild side effect profile compared to most depression treatments. The most common complaint is a headache during or right after the session. Scalp pain or discomfort at the site of stimulation is also frequently reported, along with facial twitching from stimulation of nearby nerves (occurring in about 21% of patients). Some people experience dizziness or lightheadedness.
There is a small risk of hearing changes from the repetitive clicking sounds, which is why you’ll wear earplugs during every session. The most serious risk is seizure, but current evidence puts that probability at roughly 0.03%, making it extremely rare with no evidence of permanent damage. Some patients report insomnia or increased anxiety, though these may reflect ongoing depression symptoms rather than a direct effect of the treatment.
Who Can and Cannot Get TMS
TMS is not safe for everyone. The primary concern is any non-removable metal in or near your head within about 30 centimeters of the treatment coil. This includes certain types of implants, metal plates, or clips. Ferromagnetic materials can heat up or shift position under the magnetic field, and conductive materials can have electrical currents induced in them.
Implanted devices controlled by physiological signals are also a contraindication, even if the device itself is located far from the head. This includes deep brain stimulators and cochlear implants. People wearing a wearable cardioverter-defibrillator should not receive TMS either.
Several other situations call for extra caution rather than an outright ban: pregnancy, childhood or adolescence (TMS remains off-label for younger patients), unstable heart disease or cardiac pacemakers, medication pumps, and the use of medications known to lower the seizure threshold, such as certain older antidepressants and antipsychotics.
How TMS Compares to ECT
ECT remains the most effective brain stimulation therapy for severe depression, but it comes with significant trade-offs. ECT requires general anesthesia and deliberately triggers a brief controlled seizure in the brain. Side effects include headaches, muscle soreness, nausea, and most notably, short-term memory loss that can occasionally extend to longer-term memory difficulties.
TMS requires no anesthesia, causes no seizures by design, and has no meaningful effect on memory or cognition. You can return to work or normal activities immediately after each session. The trade-off is that TMS is generally less potent than ECT for the most severe or urgent cases of depression. For many people with treatment-resistant depression who want to avoid the demands and cognitive risks of ECT, TMS offers a gentler alternative.
Insurance Coverage and Cost
Medicare and most private insurers cover TMS for major depressive disorder, but with conditions. You typically need to demonstrate that at least one antidepressant medication has failed at an adequate dose and duration, or that you couldn’t tolerate the side effects of medication. The specific requirements for what counts as a “failed trial” follow FDA labeling guidelines for dosing and treatment length.
Without insurance, a full course of TMS can cost several thousand dollars. Coverage policies vary between insurers, so verifying your specific plan’s requirements before starting treatment is worth the effort. Many TMS clinics have staff dedicated to navigating insurance approvals.
What Happens After Treatment Ends
If TMS works for you, the improvements typically become noticeable partway through the treatment course and continue to build. The benefits last at least two to three months for most responders. If symptoms return after that window, you can repeat a full course of TMS.
Whether ongoing “maintenance” sessions (periodic treatments after the initial course to prevent relapse) are beneficial remains an open question. Some clinics offer maintenance protocols, but there isn’t yet strong enough evidence to know whether they reliably keep depression from returning. For now, the standard approach is to complete the initial course and pursue retreatment if and when symptoms recur.