How TMS works
TMS stands for transcranial magnetic stimulation. Inside the coil, a strong, focused magnetic pulse — about the strength of an MRI magnet, switched on and off in rapid pulses — passes through scalp and skull without surgery. Where it lands, it creates a tiny electrical signal and the brain cells under the coil fire. Session after session, those repeated firings strengthen the activity and connections of the targeted circuit.
For depression the target is usually the DLPFC on the left side, where raising activity lifts mood, energy, and drive. For other conditions the target, side, pulse speed, and coil differ — which is why the machine and protocol are medical decisions, not details.
You are awake the whole time, sitting in a chair. There is no anesthesia, no sedation, no memory loss, and no recovery room. You drive yourself home and return to work or family the same hour. Nothing is implanted and nothing stays in the body afterwards.
The first treatment day: mapping and motor threshold
- You sit in the treatment chair. The coil is placed over the scalp above the brain's hand-control area.
- Single pulses are given at slowly rising strength while the technician watches your hand. The lowest strength that makes your thumb twitch reliably is your motor threshold — your own calibration number. Treatment strength is set as a percentage of it, so dosing is personal.
- The coil moves forward to the treatment target, located by head measurements or, with Ampa and some other systems, by camera guidance and a marked cap.
- A full session is usually given the same day or the next visit.
Every session after that
- Check in: sleep, mood, headaches, medicine changes, alcohol use, anything new medically.
- Ear protection goes in. The machine clicks loudly with each pulse train. Hearing protection is standard, not optional.
- Treatment: a tapping or knocking feeling on the scalp, in bursts — a few seconds of rapid taps, then a rest, repeating. Standard sessions run about 19–40 minutes depending on system and protocol. Theta-burst compresses the pattern into about 3 minutes.
- Discomfort, if any, is worst in the first week and usually fades. Tell the technician — small adjustments are normal care.
- You leave. No grogginess, no observation period, no ride needed.
Schedule: for standard courses, five days a week for about six weeks — 30 to 36 sessions, typically run over six to nine weeks. BrainsWay depression courses are often 20 sessions over four weeks plus twice-weekly continuation. Ampa clinics may offer compressed schedules. Ask your clinic for its specific calendar, in writing. Scores such as the PHQ-9 should be re-measured every week or two during the course.
How well does it work?
In the trials that won clearance, TMS beat a sham (sound-and-sensation-matched fake) treatment by a clear margin in people whose depression had already resisted medicine. In large real-world clinic registries, roughly eight in ten people who completed a course and were re-measured showed measurable improvement, and roughly six in ten reached remission in NeuroStar's published real-world data. Two cautions belong beside those numbers: registries count finishers, which flatters results, and no two histories are the same. Benefits often begin in weeks two to four, are usually gradual — sleep, energy, and patience often improve before mood — and can last many months. Depression can return; some people need maintenance sessions or a repeat course. Ambetter does not cover maintenance TMS under the policy reviewed for this library.
Pros and cons
Pros
- No drug through the body: no weight gain, sexual, stomach, sweating, or blood-pressure effects from a medicine level, no drug–drug interactions, no withdrawal if a day is missed.
- No anesthesia, no memory loss, no seizure induced on purpose.
- Targeted to the underactive circuit, not the whole body.
- Can be added without stopping current medicine and therapy.
- Short sessions; the rest of the day is yours.
Cons and burdens
- The calendar is the biggest cost: five trips a week for about six weeks. Missed sessions weaken a course.
- Scalp discomfort and headache, most often in week one. Jaw ache or facial twitching can occur.
- Seizure is the serious risk — rare, well under 1 in 1,000 courses in screened patients using standard settings — which is why screening matters and why new medicines, heavy alcohol use, or withdrawal during a course must be reported the same day.
- The click is loud; ringing in the ears has been reported. Wear protection every session.
- Mania switch is possible, though uncommon, in unrecognized bipolar disorder.
- Results are not permanent by default. Ask about the relapse plan before the course starts.
The machines are not interchangeable
| System | How it works | FDA-cleared for | Not cleared for |
|---|---|---|---|
| NeuroStar | Figure-8 coil, precise surface targeting. Session about 19 minutes (older protocols about 37). | Major depression in adults who failed a medicine trial; anxious depression; add-on OCD in adults; add-on depression in adolescents 15–21 (2024). | PTSD. Smoking. Generalized anxiety on its own. Bipolar depression. |
| BrainsWay Deep TMS | Cushioned helmet with an H-coil; reaches deeper and broader structures. About 20 minutes. | Major depression; anxious depression; OCD (H7, 2018); smoking cessation (H4, 2020); add-on depression in adolescents 15–21 (2025). | PTSD on its standard coils. Generalized anxiety on its own. |
| MagVenture | Figure-8 and other coils, including theta-burst protocols as short as about 3 minutes. | Major depression; OCD (certain protocols). | PTSD. Smoking. |
| Ampa One — the system CAMHP is preparing in Bude through Lumora | Lightweight handheld coil, camera-guided targeting with a printed cap, portable, plugs into a regular outlet. | Major depressive disorder in adults who did not improve enough on antidepressant medicine in the current episode. | PTSD. OCD. Smoking. Anxiety on its own. |
| SAINT / accelerated TMS | Protocol on MagVenture-type systems at specialty centers: many theta-burst sessions a day for 5 days, MRI-based targeting at the original Stanford program. | Treatment-resistant depression (SAINT protocol cleared 2022). | Everything else. Coverage differs — ask directly if accelerated treatment is proposed, and what it costs. |
| Wave MeRT | EEG and heart recordings set personal stimulation settings, then TMS is delivered on those settings. | Adjunct treatment of PTSD in adults — cleared June 2026. This system only. | That clearance does not transfer to NeuroStar, BrainsWay, MagVenture, or Ampa One. |
Safety screening — who should pause for specialist clearance
- Metal in or near the head: aneurysm clips or coils, stents, implanted electrodes or stimulators, a cochlear implant, bullet or shrapnel fragments; older tattoos with metallic ink near the site in rare cases. Dental fillings, braces history, and most hardware away from the head are usually not barriers — only the clinic can clear a specific case.
- Seizure history or epilepsy, brain tumor, recent stroke, serious head injury, prior brain surgery, or medicines and conditions that lower the seizure threshold.
- History of mania or bipolar disorder, psychosis, or current mania symptoms.
- Active alcohol or benzodiazepine withdrawal, or substance use that changes seizure risk day to day. The clinic needs the truth here for safety, not for judgment.
- Pregnancy and hearing problems belong in the consult conversation.
- Depression with immediate suicide danger: TMS is a weeks-long course, not a crisis intervention. Safety planning and, where indicated, faster or higher-level care come first.
Thinking about medicines alongside TMS? Read Meds & Weaning.