Canadian rTMS Treatment and Biomarker Network in Depression Trial

Repetitive transcranial magnetic stimulation (rTMS) is an emerging treatment for medically refractory major depressive disorder (MDD). rTMS involves direct stimulation of cortical neurons using externally applied, powerful, focused magnetic field pulses. Dozens of studies and several meta-analyses over the last 15 years have shown that rTMS of the dorsolateral prefrontal cortex (DLPFC) produces statistically significant improvements in MDD, even when medications have failed. However, other possible targets may also yield improvement in symptoms. In an attempt to enhance the therapeutic efficacy of current interventions for TRD, attention has turned to identifying domain-specific biomarkers in hopes of ultimately individualizing and predicting treatment response. Unfortunately, the precise nature of this relationship is less than clear, as reflected by the fact that even now there are no established biomarkers that are used routinely in clinical practice to aid in diagnosis. This study also seeks to examine a comprehensive suite of biomarker measurements (MRI, neurophysiology, and genomics/proteomics) before and after rTMS treatment.