  Personalized treatments are gaining momentum across all fields of medicine.
Precision medicine can be applied to neuromodulatory techniques, where focused
brain stimulation treatments such as repetitive transcranial magnetic
stimulation (rTMS) are used to modulate brain circuits and alleviate clinical
symptoms. rTMS is well-tolerated and clinically effective for
treatment-resistant depression (TRD) and other neuropsychiatric disorders.
However, despite its wide stimulation parameter space (location, angle,
pattern, frequency, and intensity can be adjusted), rTMS is currently applied
in a one-size-fits-all manner, potentially contributing to its suboptimal
clinical response (~50%). In this review, we examine components of rTMS that
can be optimized to account for inter-individual variability in neural function
and anatomy. We discuss current treatment options for TRD, the neural
mechanisms thought to underlie treatment, differences in FDA-cleared devices,
targeting strategies, stimulation parameter selection, and adaptive closed-loop
rTMS to improve treatment outcomes. We suggest that better understanding of the
wide and modifiable parameter space of rTMS will greatly improve clinical
outcome.
