Analysis of 810 patients across 25 studies reveals critical dosing patterns for accelerated transcranial magnetic stimulation in depression treatment. Higher pulse counts, sessions exceeding 20 total treatments, and intersession intervals of 50+ minutes significantly improved antidepressant responses compared to standard protocols.
These findings address a pressing clinical need as accelerated TMS protocols gain adoption for treatment-resistant depression. Traditional TMS requires 6-8 weeks of daily sessions, while accelerated versions compress treatment into days or weeks through multiple daily sessions. However, optimal dosing has remained unclear, leading to inconsistent outcomes across centers. The dose-response relationship identified here mirrors broader neurostimulation principles: adequate neural circuit engagement requires sufficient stimulation intensity and recovery time for synaptic consolidation. The 50-minute recovery threshold likely reflects the time needed for activity-dependent plasticity mechanisms to reset between sessions. For clinicians, this suggests current accelerated protocols may be under-dosed, particularly concerning session frequency and recovery periods. The lack of difference between stimulation types (iTBS versus standard rTMS) indicates protocol timing matters more than specific technique. This represents confirmatory evidence that could standardize accelerated TMS delivery and improve response rates in the 30-40% of depressed patients who don't respond to medications.
