Able Psychiatry

Glossary

What Is rTMS?

Written by the Able Psychiatry clinical team

Updated September 27, 2026

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive treatment that delivers repeated pulses of magnetic energy through a coil placed against the scalp to activate brain cells, most often to treat major depressive disorder that has not improved with medication. Nothing is implanted.

Key takeaways

  • The FDA regulates rTMS as “an external device that delivers repetitive pulsed magnetic fields of sufficient magnitude to induce neural action potentials in the prefrontal cortex to treat the symptoms of major depressive disorder (MDD) without inducing seizure in patients who have failed at least one antidepressant medication and are currently not on any antidepressant therapy.”
  • rTMS is a family of pulse patterns, not one fixed protocol: standard high-frequency stimulation and the newer theta burst stimulation pattern are both forms of rTMS.
  • A large randomized trial found a compressed theta burst pattern worked as well as standard rTMS for depression while cutting each session from about 37.5 minutes to about 3 minutes.
  • Every rTMS session is calibrated to the individual through motor threshold, a measurement taken before treatment begins.

How rTMS works

A coil is positioned against the scalp and generates a rapidly changing magnetic field. That field passes painlessly through the skull and induces a small electrical current in the brain tissue directly beneath it, activating nearby neurons. The FDA’s guidance describes rTMS as treating the symptoms of major depressive disorder “without inducing seizure in patients who have failed at least one antidepressant medication and are currently not on any antidepressant therapy,” and treatment for depression is typically targeted to the left prefrontal cortex, an area involved in mood regulation.

Before the first session, the clinician measures each patient’s motor threshold — the weakest pulse that reliably makes a hand muscle twitch — and sets the treatment dose as a percentage of that number. In the trial that established theta burst stimulation as an alternative to standard rTMS, both forms of treatment were delivered five days a week for four to six weeks. rTMS is one member of a broader family of magnetic brain stimulation treatments; see what to expect during a TMS appointment for a session-by-session walkthrough of a course of treatment.

Types of rTMS protocols

  • Standard high-frequency rTMS: the original protocol, delivered at 10 pulses per second in sessions that ran about 37.5 minutes in a large multicenter trial.
  • Theta burst stimulation (TBS): a patterned, compressed form of rTMS delivered in about 3 minutes per session in that same trial, with equivalent effectiveness to standard rTMS.
  • Accelerated rTMS: multiple sessions delivered in a single day, used to compress a full course into days instead of weeks.
  • Maintenance rTMS: periodic sessions continued after an initial course, intended to help sustain the response and lower the chance of relapse.

Example of rTMS

The THREE-D trial, a randomized, multicenter non-inferiority trial run at three Canadian university hospitals, randomly assigned 205 participants with treatment-resistant depression to standard 10 Hz rTMS and 209 to theta burst stimulation, delivered to the left dorsolateral prefrontal cortex five days a week for four to six weeks. Depression scores (17-item Hamilton Rating Scale) improved from about 23.5 to 13.4 in both groups, and the trial concluded theta burst stimulation was non-inferior to standard rTMS. Headache was the most common side effect in both groups (about 64%-65% of participants), and dropout rates did not differ between groups.

What people get wrong

“TMS” and “rTMS” get used interchangeably, and in everyday conversation that’s fine. But rTMS specifically means the repeated-pulse form delivered across a full course of sessions, and more than one pulse pattern falls under that name. Patients are sometimes surprised to learn that “theta burst” and “standard rTMS” are both technically rTMS — the difference is the timing pattern of the pulses, not a different machine or a different treatment goal.

rTMS vs. theta burst stimulation

Standard (high-frequency) rTMS Theta burst stimulation
Pulse pattern Continuous pulses, typically 10 per second Patterned bursts, delivered intermittently
Session length (THREE-D trial) About 37.5 minutes About 3 minutes
Effectiveness (THREE-D trial) Reference standard Non-inferior to standard rTMS
Self-rated treatment discomfort (THREE-D trial, 0-10 scale) 3.4 3.8

Both are forms of rTMS. Theta burst stimulation is a faster-to-deliver pulse pattern, not a separate treatment or a different machine.

Frequently asked questions

Is rTMS the same thing as TMS?
In everyday conversation, yes — most people say “TMS” to mean rTMS. The FDA’s device category for standard depression treatment courses is specifically named “Repetitive Transcranial Magnetic Stimulation (rTMS) Systems.”

How many sessions are in a typical rTMS course?
In the large trial that established theta burst stimulation as equivalent to standard rTMS, both were delivered five days a week for four to six weeks. Exact schedules vary by protocol and by clinic.

Does rTMS hurt?
Most people describe a tapping or knocking sensation on the scalp rather than pain. In a large clinical trial, participants rated the sensation around 3 to 4 out of 10 on average, whether they received standard rTMS or theta burst stimulation.

The bottom line

rTMS is a family of magnetic brain stimulation protocols, regulated by the FDA to treat major depressive disorder that hasn’t responded to medication. Every course starts with an individual motor threshold measurement, and newer variations — theta burst, accelerated, and maintenance schedules — are all still built on the same repeated-pulse principle.

Sources

Considering TMS? Read what to expect at a TMS appointment, or learn about TMS treatment at Able Psychiatry in Chicago.

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