Early Brainwave Biomarkers for Personalized Neuromodulation in Treatment-resistant Depression

This study tests whether a brain stimulation treatment for depression called intermittent theta burst stimulation (iTBS) can be improved by tailoring it to each individual. A type of brain signal measured with electroencephalography (EEG) after a single pulse of brain stimulation, called an early local TMS-evoked potential (EL-TEP), is used to identify which stimulation settings work best for each participant. The investigators will compare individualized (personalized) iTBS settings to standard (non-personalized) settings and to inactive (sham) stimulation. Participants are adults with treatment-resistant depression.