Major depressive disorder (MDD) is associated to affected brain wiring. Little is known whether these changes are stable over time and hence might represent a biological predisposition, or whether these are state markers of current disease severity and recovery after a depressive episode. Human white matter network (“connectome”) analysis via network science is a suitable tool to investigate the association between affected brain connectivity and MDD. This study examines structural connectome topology in 464 MDD patients (mean age: 36.6 years) and 432 healthy controls (35.6 years). MDD patients were stratified categorially by current disease status (acute vs. partial remission vs. full remission) based on DSM-IV criteria. Current symptom severity was assessed continuously via the Hamilton Depression Rating Scale (HAMD). Connectome matrices were created via a combination of T1-weighted magnetic resonance imaging (MRI) and tractography methods based on diffusion-weighted imaging. Global tract-based metrics were not found to show significant differences between disease status groups, suggesting conserved global brain connectivity in MDD. In contrast, reduced global fractional anisotropy (FA) was observed specifically in acute depressed patients compared to fully remitted patients and healthy controls. Within the MDD patients, FA in a subnetwork including frontal, temporal, insular, and parietal nodes was negatively associated with HAMD, an effect remaining when correcting for lifetime disease severity. Therefore, our findings provide new evidence of MDD to be associated with structural, yet dynamic, state-dependent connectome alterations, which covary with current disease severity and remission status after a depressive episode.

重度抑郁症 (MDD) 与受影响的大脑接线有关。很少有人知道这些变化是否会随着时间的推移保持稳定，因此可能代表一种生物学倾向，或者这些变化是否是当前疾病严重程度和抑郁发作后恢复的状态标志。通过网络科学进行的人类白质网络（“连接组”）分析是研究受影响的大脑连接与 MDD 之间关联的合适工具。本研究检查了 464 名 MDD 患者（平均年龄：36.6 岁）和 432 名健康对照者（35.6 岁）的结构连接组拓扑。MDD 患者根据 DSM-IV 标准按当前疾病状态（急性与部分缓解与完全缓解）进行分类。通过汉密尔顿抑郁量表（HAMD）持续评估当前症状严重程度。连接组矩阵是通过结合 T1 加权磁共振成像 (MRI) 和基于扩散加权成像的纤维束成像方法创建的。未发现基于全局路径的指标显示疾病状态组之间的显着差异，这表明 MDD 中存在保守的全局大脑连接。相比之下，与完全缓解的患者和健康对照相比，在急性抑郁症患者中特别观察到整体分数各向异性 (FA) 降低。在 MDD 患者中，包括额叶、颞叶、岛叶和顶叶节点的子网络中的 FA 与 HAMD 呈负相关，在校正终生疾病严重程度时仍然存在这种影响。因此，我们的研究结果提供了新的证据证明 MDD 与结构性的、动态的、依赖于状态的连接组改变有关，