At present, the etiology and pathogenesis of major depressive disorder (MDD) are still not clear. Studies have found that the risk of first-degree relatives of MDD is 2–3 times that of the general population. Diffusion tensor imaging (DTI) has been previously used to explore the pathogenesis of MDD. The purpose of this study is to explore the etiology of MDD by DTI and further to explore the correlation between its clinical characteristics and the structural changes of white matter in the brain. The study included 27 first-episode, drug-naive patients with MDD, 16 first-degree relatives without MDD, and 28 healthy control subjects with no family history of MDD (HC). Results showed that the fractional anisotropy (FA) differences among the three groups were mainly in the left anterior thalamic radiation (LATR), right anterior thalamic radiation (RATR), left corticospinal tracts (LCST), forceps major (FMa), right inferior longitudinal fasciculus (RILF), and left superior longitudinal fasciculus (temporal) (LSLF(T)). Among the 6 sites, LCST, FMa, and LSLF(T) showed significant differences between MDD and First-degree relatives compared to HC. MDD patients had significant emotional symptoms, somatic symptoms, and cognitive impairment. FMa FA was significantly positively correlated with delayed memory score (, ), and RILF FA was significantly negatively correlated with the FSS score (, ). These results revealed that the white matter characteristics of MDD-susceptible patients were LCST, FMa, and LSLF(T) lesions, all of which may be quality indicators of MDD.

中文翻译：

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左皮质脊髓束、大钳和左上纵束（颞叶）的损伤作为重度抑郁症的质量指标

目前，重度抑郁症（MDD）的病因和发病机制尚不明确。研究发现，一级亲属患MDD的风险是普通人群的2-3倍。扩散张量成像 (DTI) 以前已用于探索 MDD 的发病机制。本研究旨在探讨DTI引起MDD的病因，进一步探讨其临床特征与脑白质结构变化的相关性。该研究包括 27 名首发未用药的 MDD 患者、16 名无 MDD 的一级亲属和 28 名无 MDD 家族史的健康对照受试者（HC）。结果显示，三组间各向异性分数（FA）差异主要表现在左丘脑前辐射（LATR），右前丘脑辐射 (RATR)、左皮质脊髓束 (LCST)、大钳 (FMa)、右下纵束 (RILF) 和左上纵束 (颞) (LSLF(T))。在 6 个站点中，LCST、FMa 和 LSLF(T) 显示 MDD 和一级亲属与 HC 相比存在显着差异。MDD患者有明显的情绪症状、躯体症状和认知障碍。FMa FA 与延迟记忆评分呈显着正相关（躯体症状和认知障碍。FMa FA 与延迟记忆评分呈显着正相关（躯体症状和认知障碍。FMa FA 与延迟记忆评分呈显着正相关（, ), RILF FA 与 FSS 评分显着负相关 (, ）。这些结果表明，MDD易感患者的白质特征为LCST、FMa和LSLF(T)病变，这些都可能是MDD的质量指标。