Background: Alterations of the hypothalamic-pituitary-adrenal (HPA) axis are common in patients diagnosed with major depressive disorder (MDD). Nevertheless, these alterations are not found in every patient. There is evidence to indicate a possible mediating role of early life stress (ELS) in the relation between dysfunction of the HPA axis and MDD. We conducted a systematic review to understand if the alterations of the HPA axis commonly found in patients with MDD are due to early life stress or are caused by the disorder itself. Methods: The review was conducted by following the PRISMA guidelines. Original articles were found in PubMed and via a manual search. Only studies whose design allowed comparison of the HPA functioning in the 4 groups no-MDD/no-ELS, MDD/no-ELS, no-MDD/ELS, and MDD/ELS were included. Results: Hyperactivity or hypoactivity of the HPA axis was found in 8 articles. A greater number of abnormalities and a higher rate of posttraumatic stress disorder comorbidity were found in the MDD/ELS group. Dysfunction of the HPA axis was also found in the no-MDD/ELS groups. Conclusion: HPA dysfunction found in MDD seems to be more related to the presence of ELS rather than to the MDD itself. Future studies are needed to clarify the exact mechanisms involved.
Neuropsychobiology

中文翻译：

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在重度抑郁症患者中观察到的 HPA 轴的变化及其与早期生活压力的关系：系统评价

背景：下丘脑-垂体-肾上腺（HPA）轴的改变在诊断为重度抑郁症（MDD）的患者中很常见。然而，并非在每个患者中都发现这些改变。有证据表明早期生活压力 (ELS) 在 HPA 轴功能障碍与 MDD 之间的关系中可能具有中介作用。我们进行了系统评价，以了解 MDD 患者中常见的 HPA 轴的改变是由于早期生活压力还是由疾病本身引起的。方法：审查是按照 PRISMA 指南进行的。原始文章是在 PubMed 中通过手动搜索找到的。仅包括其设计允许比较 4 组无 MDD/无 ELS、MDD/无 ELS、无 MDD/ELS 和 MDD/ELS 中 HPA 功能的研究。结果：在8篇文章中发现HPA轴活动过度或活动不足。在 MDD/ELS 组中发现更多的异常和更高的创伤后应激障碍合并症发生率。在无 MDD/ELS 组中也发现了 HPA 轴功能障碍。结论： MDD 中发现的 HPA 功能障碍似乎与 ELS 的存在有关，而不是与 MDD 本身有关。需要进一步的研究来阐明所涉及的确切机制。
神经心理生物学