# The Use of MRI and TMS in Treatment-Resistant Depression: Advances in Pediatric Applications

## TL;DR

This review explores how MRI and TMS can help treat depression in adolescents who do not respond to traditional therapies.

## Contribution

The paper highlights advances in using fMRI to guide TMS protocols for treatment-resistant depression in adolescents.

## Key findings

- TMS is a promising non-invasive treatment for adolescents with treatment-resistant depression.
- fMRI helps understand how TMS affects brain connectivity in adolescents with MDD.
- Neuroimaging-guided TMS offers a new therapeutic approach for adolescents unresponsive to conventional treatments.

## Abstract

Treatment-resistant depression (TRD) is a substantial burden for psychiatric care, affecting approximately one-third of patients with major depressive disorder (MDD). Adolescent populations with depression are a particularly challenging demographic to treat as early intervention is crucial to prevent treatment resistance, but treatment options are limited. Transcranial magnetic stimulation (TMS) has emerged as a promising non-invasive option for TRD in adults as well as adolescents, offering hope for patients who have not responded to conventional therapies. This review examines the convergence of functional magnetic resonance imaging (fMRI) as a tool to examine how TMS modulates functional connectivity in adolescents with MDD. Such analyses have led to advances in our understanding of the pathophysiology of MDD, TRD, and the mechanisms of TMS. We review this evidence, evaluate methodological approaches, and identify critical gaps in the existing literature, highlighting how neuroimaging-guided TMS protocols offer a promising therapeutic avenue for adolescent TRD, particularly in cases where conventional treatments have proven ineffective.