Comprehensive Summary
This study, presented by Liu et al., investigated dysregulation within the inhibitory control network as a predictor of response to antidepressant medication. 72 patients with Major Depressive Disorder (MDD) were recruited, and data was collected using clinical evaluations, demographic details, magnetoencephalography (MEG) and MRI scans; data was also collected from 77 healthy controls (HC). Participants received MEG scans while performing a Go/No-go task associated with response inhibition. All patients received serotonin selective reuptake inhibitor (SSRI) monotherapy for at least four weeks and were classified as responders or non-responders. Functional connectivity was compared between patients and HCs and responders (those whose MDD symptoms improved with medication) and non-responders using the network-based statistics (NBS) toolbox. Individuals with MDD had reduced connectivity in a right-lateralized frontal network compared to the control group. Non-responders showed significantly decreased connectivity within the left-lateralized frontoparietal network compared to responders, and connectivity in this network at baseline was significantly correlated with decrease in depression symptoms after treatment. This indicates a potential biomarker for poor antidepressant response. The results of this study suggest that reduced beta-band connectivity leading to decreased top-down modulation may be responsible for response inhibition impairment in MDD.
Outcomes and Implications
Despite a wide range of available treatments for MDD, many patients fail to respond to multiple therapies. Trialing antidepressants takes time and repeated failures may cause patients to withdraw from treatment. Being able to use biomarkers to identify potential responders and non-responders could allow for tailored treatment options and improved patient outcomes. However, this study has multiple limitations: it employed a cross-sectional design, it has a relatively small sample size, analysis was restricted to patients undergoing SSRI monotherapy, and MEG is a high-cost instrument, which may limit clinical applicability. Further studies are recommended to examine changes following treatment.