Theta Burst Stimulation (TBS): The Faster TMS Protocol Explained
At a Glance
- Theta burst stimulation (TBS) is a newer TMS protocol that delivers the same therapeutic effect in 3 minutes instead of the standard 37-minute session.
- FDA cleared for major depressive disorder in 2018 after the THREE-D trial showed iTBS was non-inferior to standard 10 Hz rTMS.
- The Stanford SAINT protocol uses accelerated iTBS (10 sessions per day for 5 days) and showed a 79% remission rate in treatment-resistant depression.
- Same side effects as standard TMS: scalp discomfort, headache, rare seizure risk (~0.01%).
What Is Theta Burst Stimulation?
Standard repetitive TMS (rTMS) delivers magnetic pulses at a steady rate (typically 10 Hz) for 37 minutes per session. Theta burst stimulation uses a different pattern: bursts of 3 pulses at 50 Hz, repeated at 5 Hz (the theta rhythm). This patterned delivery produces longer-lasting changes in cortical excitability in a fraction of the time.
There are two main TBS protocols:
Intermittent TBS (iTBS)
2 seconds of stimulation followed by 8 seconds of rest, repeated for about 3 minutes (600 total pulses). iTBS increases cortical excitability, similar to standard high-frequency rTMS. This is the FDA-cleared protocol for depression, targeting the left dorsolateral prefrontal cortex (DLPFC).
Continuous TBS (cTBS)
40 seconds of uninterrupted theta burst delivery (600 pulses). cTBS decreases cortical excitability. It is used experimentally for conditions where reducing activity in a brain region is the goal (e.g., right DLPFC stimulation for certain anxiety patterns).
The THREE-D Trial
The landmark study that led to FDA clearance. This multicenter, randomized, non-inferiority trial compared iTBS (3 minutes) to standard 10 Hz rTMS (37 minutes) in 414 patients with treatment-resistant depression. Results: iTBS was non-inferior to standard rTMS on all outcome measures, with similar response rates (~49%) and remission rates (~32%). The study was published in The Lancet in 2018 and fundamentally changed the practical delivery of TMS by making sessions dramatically shorter.
The Stanford SAINT Protocol
Stanford researchers took iTBS further. Instead of one session per day over 6 weeks, the SAINT (Stanford Accelerated Intelligent Neuromodulation Therapy) protocol delivers 10 iTBS sessions per day for 5 consecutive days (50 total sessions in one week). Each session is spaced 50 minutes apart.
Results from the initial open-label study and subsequent randomized sham-controlled trial were remarkable: 79% remission rate in treatment-resistant depression (compared to ~13% with sham). This is among the highest remission rates ever reported for any depression treatment. The protocol uses functional MRI-guided targeting to personalize the exact stimulation location for each patient.
Access note: The full SAINT protocol requires fMRI-guided targeting and is not widely available yet. Some clinics offer “accelerated TMS” protocols inspired by SAINT but without the fMRI personalization. These may still be beneficial but are not identical to the published protocol. Ask whether the clinic uses fMRI-guided or standard anatomical targeting.
TBS vs Standard TMS
| Feature | Standard rTMS (10 Hz) | iTBS | SAINT Protocol |
|---|---|---|---|
| Session duration | 37 minutes | 3 minutes | 3 min x 10/day |
| Total sessions | 30-36 (6 weeks) | 30-36 (6 weeks) | 50 (1 week) |
| Total treatment time | ~20 hours | ~2 hours | ~2.5 hours (1 week) |
| Efficacy | ~49% response | ~49% response (non-inferior) | ~79% remission |
| FDA cleared | Yes (2008) | Yes (2018) | Yes (2022, Magnus Medical) |
