Comparing effects of differing frequencies of transcranial magnetic stimulation—A systematic review

Introduction: The effects of repetitive transcranial magnetic stimulation (rTMS) are determined in part by pulse frequency, which can inhibit or activate targeted cortical regions and modulate synaptic plasticity. Despite numerous indications for the clinical use of rTMS, optimal stimulation frequencies and other treatment parameters remain unclear. This systematic review synthesizes the head-to-head evidence that examines how rTMS frequencies affect clinical, cognitive, and biometric outcomes. Methods: Following PRISMA guidelines (PROSPERO CRD42024607740), a systematic literature search was conducted in PubMed, Embase, and PsycINFO. The search included articles published through May 2026 that compared two or more rTMS frequencies while maintaining consistent cortical targets and study parameters within each experiment. Two independent reviewers screened each study, extracted data, and assessed risk of bias. Due to heterogeneity of the study designs, the findings were analyzed qualitatively. Results: Of the resulting 9388 records spanning psychiatric, neurologic, healthy, and preclinical populations, 145 studies met the inclusion criteria. Studies were categorized by population, and the following data were extracted: study design, disease state, demographic data, stimulation parameters, outcome measures, tolerability and safety outcomes, pharmacotherapy status, and dropout rates. Conclusion: Frequency plays an important, but not determinative, role in the efficacy of rTMS. Future research, particularly studies incorporating baseline neurophysiology and systematic variation of stimulation parameters, is needed to further optimize treatment protocols and enhance treatment efficacy.