A Dose-Finding, Biomarker Validation, and Effectiveness Study of Transcranial Magnetic Stimulation for Adolescents With Depression

Abstract

Research and clinical application of transcranial magnetic stimulation (TMS) for adolescents with major depressive disorder (MDD) has advanced slowly. Significant gaps persist in our understanding of optimized, age-specific protocols and dosing strategies. This study aimed to compare the clinical effects of 1 Hz versus 10 Hz TMS regimens and examine a biomarker-informed treatment approach with glutamatergic intracortical facilitation (ICF). Participants with moderate-to-severe symptoms of MDD were randomized to 30 sessions of left prefrontal 1 Hz or 10 Hz TMS, stratified by baseline ICF measures. The primary clinical outcome measure was the Children's Depression Rating Scale, Revised (CDRS-R). The CDRS-R and ICF biomarker were collected weekly. Forty-one participants received either 1 Hz (n = 22) or 10 Hz (n = 19) TMS treatments. CDRS-R scores improved compared to baseline in both 1 Hz and 10 Hz groups. For participants with low ICF at baseline, the overall least squares means of CDRS-R scores over the 6-week trial showed that depressive symptom severity was lower for the group treated with 1 Hz TMS than for those who received 10 Hz TMS. There were no significant changes in weekly ICF measurements across the 6 weeks of TMS treatment. Low ICF may reflect optimal glutamatergic N-methyl-d-aspartate (NMDA) receptor activity that facilitates the therapeutic effect of 1 Hz TMS through long-term depression-like mechanisms on synaptic plasticity. The stability of ICF suggests that it is a tonic, trait-like measure of NMDA receptor-mediated neurotransmission, with potential utility to inform parameter selection for therapeutic TMS in adolescents with MDD.