Accelerated TMS has generally demonstrated a safety and tolerability profile similar to other forms of TMS when appropriate treatment parameters are used.

Commonly reported side effects include:

Headache

Scalp discomfort

Treatment-site pain or sensitivity

Fatigue

Facial or scalp muscle movement

Dizziness

Temporary discomfort during stimulation

A review examining accelerated TMS across multiple psychiatric conditions found headache, fatigue and scalp discomfort among the most frequently reported adverse effects and found serious complications to be uncommon.

Because accelerated treatment delivers several stimulation sessions during the same day, fatigue or treatment-site discomfort may be more noticeable for some patients.

For example, a 2026 randomized trial comparing accelerated iTBS with conventional high-frequency treatment found that treatment-site discomfort and headaches were more common in the accelerated group, although the accelerated protocol remained generally well tolerated.

Seizure remains a recognized but rare serious risk of TMS. Clinical screening, appropriate spacing between treatment sessions and adherence to evidence-based stimulation parameters are therefore particularly important when multiple treatments are delivered during the same day.

The evidence for accelerated TMS has grown substantially.

Earlier systematic reviews suggested that accelerated TMS could reduce depressive symptoms, although researchers emphasized that studies varied considerably in treatment dose, targeting method, number of sessions and overall treatment schedule.

More recent evidence has strengthened support for accelerated theta-burst approaches.

A 2026 systematic review and meta-analysis examined 15 randomized sham-controlled trials involving 704 adults with major depressive episodes.

Accelerated iTBS produced significantly greater improvement in depressive symptoms than sham treatment. 

Patients receiving active accelerated iTBS were approximately twice as likely to meet study-defined response criteria, and remission was also significantly more likely with active treatment.

The researchers estimated a number needed to treat approximately 5 for clinical response and 10 for remission, while discontinuation rates were similar between active and sham treatment groups.

The analysis also identified an important point: accelerated TMS is not simply about delivering treatment as quickly as possible.

Outcomes appeared to be influenced by factors including:

Number of treatment sessions

Total stimulation dose

Time between treatment sessions

Treatment target

Whether functional-connectivity-based neuronavigation was used

This supports the idea that the design of an accelerated protocol matters, not just the number of sessions delivered each day.

A separate 2026 multisite randomized trial compared an accelerated iTBS schedule with standard high-frequency TMS in 104 adults with moderate-to-severe MDD. Both groups experienced substantial improvement, and accelerated treatment met the study's criteria for non-inferiority while producing faster symptom reduction during the earlier phase of treatment.

Potentially.

The primary advantage of accelerated TMS is that a larger proportion of the treatment course can be completed within a shorter period.

Some studies have also observed earlier clinical improvement compared with conventional schedules.

However, "accelerated" refers primarily to how treatment sessions are scheduled rather than guaranteeing that every patient will experience immediate symptom relief.

Some individuals may notice improvement during the treatment course, while others may continue improving after the final treatment session.