# The Deteriorated Center-Surround Suppression in Patients With First-Episode and Drug-Naïve Major Depressive Disorder

## TL;DR

This study finds that first-episode, drug-naïve major depressive disorder patients have reduced visual inhibition, suggesting a potential early marker for the condition.

## Contribution

The study is the first to show deteriorated center-surround suppression in first-episode, drug-naïve MDD patients.

## Key findings

- CSS was significantly reduced in FEDN MDD patients compared to healthy controls.
- CSS impairments in FEDN MDD patients differ from those in acute and recovered MDD patients.
- Motion repulsion was not significantly different between FEDN MDD patients and controls.

## Abstract

Background: Major depressive disorder (MDD) patients are often associated with inhibition deficits in the visual cortex. Most previous research has focused on visual inhibition in MDD patients during acute and remission phases, with little research on first-episode and drug-naïve (FEDN) patients. To fill this gap, we psychophysically investigated the inhibitory process of visual motion in patients with FEDN MDD.

Methods: Two psychophysical tasks: Center-Surround Suppression (CSS) and Motion Repulsion (MR) were utilized to investigate the presence of visual perceptual inhibition deficits in patients with FEDN MDD. We collected data from 74 patients with FEDN MDD and 68 healthy controls (HCs) matched for age, years of education, and gender. We also measured the Hamilton Depression Rating Scale, 17-item (HAMD-17) for each patient to assess the severity of depressive symptoms.

Results: The results showed that CSS was significantly deteriorated in FEDN MDD patients (p=0.001), but it did not correlate with the HAMD score (p > 0.05). In addition, no significant differences were observed between the two groups of subjects in terms of gender, age, and education level (all p > 0.05). Analysis of two previously published datasets using the same CSS task involving MDD patients in different illness stages revealed that the levels of CSS reduction in our FEDN patients were also significantly distinguishable from those in acute and recovered MDD patients (all p < 0.01). This quantitative comparison indicates that CSS impairments are dynamic over the course of illness development. Moreover, the magnitudes of MR showed no significant differences between MDD patients and HCs (all p > 0.05).

Conclusions: Our study was the first to demonstrate the deteriorated CSS in patients with FEDN MDD. Notably, inhibitory deficits in MDD are also highly specific, as MDD affects only the CSS, but not the MR. Therefore, the discrepancy between these two psychophysical tasks suggests CSS may serve as a feasible early marker in MDD. These findings offer new insights into the specific visual cortical deficits in patients with FEDN MDD.

Limitation: The current study lacks imaging data to support the perceptual phenomenon we observed.