Brain connectivity in major depressive disorder: a precision component of treatment modalities?

Abstract

Major depressive disorder (MDD) is a very prevalent mental disorder that imposes an enormous burden on individuals, society, and health care systems. Most patients benefit from commonly used treatment methods such as pharmacotherapy, psychotherapy, electroconvulsive therapy (ECT), and repetitive transcranial magnetic stimulation (rTMS). However, the clinical decision on which treatment method to use remains generally informed and the individual clinical response is difficult to predict. Most likely, a combination of neural variability and heterogeneity in MDD still impedes a full understanding of the disorder, as well as influences treatment success in many cases. With the help of neuroimaging methods like functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI), the brain can be understood as a modular set of functional and structural networks. In recent years, many studies have investigated baseline connectivity biomarkers of treatment response and the connectivity changes after successful treatment. Here, we systematically review the literature and summarize findings from longitudinal interventional studies investigating the functional and structural connectivity in MDD. By compiling and discussing these findings, we recommend the scientific and clinical community to deepen the systematization of findings to pave the way for future systems neuroscience roadmaps that include brain connectivity parameters as a possible precision component of the clinical evaluation and therapeutic decision.

Increased anti-correlation between the left dorsolateral prefrontal cortex and the default mode network following Stanford Neuromodulation Therapy (SNT): analysis of a double-blinded, randomized, sham-controlled trial

“…Targeting of the L-DLPFC in the present study is predicated on identifying clusters that are maximally negatively connected to the sgACC, for which there remains an abundance of evidence supporting baseline target-sgACC functional connectivity as a strong predictor of antidepressant response 21 . As such, we were particularly interested in whether a novel form of accelerated, excitatory (aiTBS) stimulation delivered to the personalized target might elicit subsequent target-sgACC functional connectivity changes, in contrast to previous studies utilizing traditional 10 Hz rTMS 7 .…”

Structural Brain Connectivity and Treatment Improvement in Mood Disorder

“…More recently, a review focusing on functional and structural connectivity in MDD patients under treatment found modified FA in the white matter tracts of multiple regions, such as the hippocampus, raphe nucleus or amygdala in treatment responders compared to non-responders. Alterations in other DTI parameters, namely the axial diffusivity and radial diffusivity were also associated with clinical response in white matter tracts (Tura and Goya-Maldonado, 2023). In these articles, voxel-wise combined with mass-univariate linear analyses were key in identifying these regions.…”

Potential Inflammatory Biomarkers for Major Depressive Disorder Related to Suicidal Behaviors: A Systematic Review

“…Characterized by depressive mood; diminished motivation; and a mixed array of cognitive, mental, and physical symptoms, MDD contributes to a significant decline in daily functioning [ 8 ]. According to the Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5), the diagnosis of MDD requires at least five persistent symptoms for a minimum duration of 2 weeks [ 9 ]. The disease adversely affects quality of life [ 10 ] and contributes to premature morbidity and mortality, primarily through suicidal behavior [ 10 ].…”