Individualized Connectivity-Guided Versus Conventional Targeting of Accelerated Theta-Burst Stimulation in Depression: A Randomized, Double-Blind, Parallel-Design Trial.

Abstract

Scalp-based repetitive transcranial magnetic stimulation targeting the left dorsolateral prefrontal cortex (DLPFC) does not account for interindividual variability. This trial was designed to determine whether individualized connectivity-guided intermittent theta-burst stimulation (iTBS) improves antidepressant outcomes compared with 5-cm targeting. In this single-center, randomized, double-blind, three-arm trial (February 2023-March 2025), adults ages 18-65 years with major depressive disorder or bipolar II depression (≥1 antidepressant failure) were randomly assigned to receive 20 sessions of iTBS over 2 weeks using robotic neuronavigation with one of three targeting strategies: 5-cm rule, functional connectivity (FC)-guided targeting showing negative resting-state connectivity with the subgenual anterior cingulate cortex (sgACC), or structural connectivity (SC)-guided sites defined by probabilistic tractography to the sgACC. The primary outcome was percentage reduction in 17-item Hamilton Depression Rating Scale (HAM-D) score at week 2. Secondary outcomes included HAM-D score reduction at weeks 6 and 12, response or remission, self-reported symptoms, performance on a cognitive battery, and adverse events. Of 123 randomized participants, 119 were included in the modified intention-to-treat analyses (5-cm, N=40; SC-guided, N=39; FC-guided, N=40). SC-guided iTBS produced significantly greater HAM-D score reduction than the 5-cm rule at week 2 (least squares mean difference [LSMD]=8.79 percentage points, 95% CI=2.19, 15.40; Cohen's d=0.70). At week 6, both SC-guided and FC-guided groups showed significantly greater improvement than the 5-cm group (SC-guided LSMD=12.87 percentage points, 95% CI=6.21, 19.54; Cohen's d=1.03; and FC-guided LSMD=9.41 percentage points, 95% CI=2.84, 15.98; Cohen's d=0.75). By week 12, between-group differences were no longer significant. Adverse events were comparable across groups, with no seizures or mania. SC-guided iTBS produced promising preliminary evidence of improved antidepressant response compared with 5-cm targeting, supporting sgACC-based connectivity-guided precision neuromodulation in depression.