Background: Noninvasive brain stimulation is typically delivered once daily, but accelerated protocols delivering multiple daily treatments have re-emerged to shorten time to clinical improvement.

Methods: At the Neuroscience School of Advanced Studies Non-Invasive Brain Stimulation Challenge Workshop (Crans-Montana, Switzerland, October 21-24, 2025), we reviewed the literature on accelerated protocols across noninvasive brain stimulation modalities such as electroconvulsive therapy (ECT), transcranial magnetic stimulation (TMS), transcranial electrical stimulation (tES), transcranial vagus nerve stimulation (tVNS), and transcranial focused ultrasound (tUS). Accelerated protocols were defined as multiple daily treatments (≥2/day).

Results: Accelerated ECT protocols date back to the 1960s, when multiple seizure inductions per day produced more rapid clinical improvement but greater cognitive adverse effects. Accelerated TMS protocols emerged in the mid-2000s and gained popularity in the late 2010s, when protocols delivering more than three treatments per day began to show faster antidepressant effects. Accelerated protocols with other modalities or for indications other than major depressive disorder are in early stages.

Discussion: Accelerated protocols may reduce response latency without diminishing response magnitude. However, the durability of accelerated protocols remains unclear, and systematic exploration of parameter space across modalities is needed.