Department of Psychiatry, First Affiliated Hospital of Kunming Medical University.
Yunnan Clinical Research Center for Mental Disorders.
Neuroreport. 2023 Jun 7;34(10):493-500. doi: 10.1097/WNR.0000000000001915. Epub 2023 May 31.
Evidence from previous literature suggests that the nucleus accumbens (NAc), hippocampus, and amygdala play critical roles in the reward circuit. Meanwhile, it was also suggested that abnormalities in the reward circuit might be closely associated with the symptom of anhedonia of depression. However, few studies have investigated the structural alterations of the NAc, hippocampus, and amygdala in depression with anhedonia as the main clinical manifestation. Thus, the current study aimed to explore the structural changes of the subcortical regions among melancholic depression (MD) patients, especially in the NAc, hippocampus, and amygdala, to provide a theoretical basis for understanding the pathological mechanisms of MD. Seventy-two MD patients, 74 nonmelancholic depression (NMD) patients, and 81 healthy controls (HCs) matched for sex, age, and years of education were included in the study. All participants underwent T1-weighted MRI scans. Subcortical structure segmentation was performed using the FreeSurfer software. MD and NMD patients had reduced left hippocampal volume compared with HCs. Meanwhile, only MD patients had reduced bilateral NAc volumes. Moreover, correlation analyses showed correlations between left NAc volume and late insomnia and lassitude in MD patients. The reduced hippocampal volume may be related to the pathogenesis of major depressive disorder (MDD), and the reduced volume of the NAc may be the unique neural mechanism of MD. The findings of the current study suggest that future studies should investigate the different pathogenic mechanisms of different subtypes of MDD further to contribute to the development of individualized diagnostic and treatment protocols.
先前的文献证据表明，伏隔核（NAc）、海马体和杏仁核在奖励回路中发挥着关键作用。同时，也有研究表明，奖励回路的异常可能与抑郁症快感缺失的症状密切相关。然而，很少有研究调查过以快感缺失为主要临床表现的抑郁症患者的 NAc、海马体和杏仁核的结构改变。因此，本研究旨在探讨抑郁障碍患者（尤其是 NAc、海马体和杏仁核）的皮质下区域结构变化，为理解抑郁障碍的病理机制提供理论依据。研究纳入了 72 例单相抑郁障碍（MD）患者、74 例非单相抑郁障碍（NMD）患者和 81 名健康对照者（HCs），并对他们进行了 T1 加权磁共振成像（MRI）扫描。采用 FreeSurfer 软件对皮质下结构进行分割。与 HCs 相比，MD 患者的左侧海马体体积减小，而 NMD 患者双侧 NAc 体积减小。此外，相关性分析显示，MD 患者的左侧 NAc 体积与晚期失眠和疲劳呈负相关。海马体体积的减少可能与重度抑郁症（MDD）的发病机制有关，而 NAc 体积的减少可能是 MD 的独特神经机制。本研究的结果表明，未来的研究应该进一步探讨不同亚型 MDD 的不同发病机制，以促进个体化诊断和治疗方案的制定。
