Institute of Medical Sciences and Technology, Shahid Beheshti University, Tehran, Iran; Department of Psychology, Humboldt-Universität zu Berlin, Berlin, Germany.
Sleep Disorders Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran.
J Affect Disord. 2019 Nov 1;258:133-143. doi: 10.1016/j.jad.2019.07.089. Epub 2019 Jul 31.
Insomnia is a common symptom of Major Depressive Disorder (MDD) and genome-wide association studies pointed to their strong genetic association. Although the prevalence of insomnia symptoms in MDD is noticeable and evidence supports their strong bidirectional association, the number of available neuroimaging findings on patients of MDD with insomnia symptoms is limited. However, such neuroimaging studies could verily improve our understanding of their shared pathophysiology and advance corresponding theories.
Based on the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guideline, we have conducted a literature search using PubMed, EMBASE, and Scopus databases and systematically explored 640 studies using various neuroimaging modalities in MDD patients with different degrees of insomnia symptoms.
Despite inconsistencies, current findings from eight studies suggested structural and functional disturbances in several brain regions including the amygdala, prefrontal cortex and anterior cingulate cortex and insula. The aberrant functional connectivity within and between the main hubs of the salience and default mode networks could potentially yield new insights into the link between MDD and insomnia, which needs further assessment.
The number of studies reviewed herein is limited. The applied methods for assessing structural and functional neural mechanisms of insomnia and depression were variable.
Neuroimaging methods demonstrated the overlapping underlying neural mechanisms between MDD and insomnia. Future studies may facilitate better understanding of their pathophysiology to allow development of specific treatment.
失眠是重度抑郁障碍（MDD）的常见症状，全基因组关联研究表明它们之间存在强烈的遗传关联。尽管 MDD 患者中失眠症状的发生率很明显，并且有证据支持它们之间的强烈双向关联，但目前可用的针对伴有失眠症状的 MDD 患者的神经影像学研究数量有限。然而，这些神经影像学研究可以真正增进我们对其共同病理生理学的理解，并推进相应的理论发展。
根据系统评价和荟萃分析的首选报告项目（PRISMA）指南，我们使用 PubMed、EMBASE 和 Scopus 数据库进行了文献检索，并系统地探索了 640 项使用各种神经影像学方法在不同程度失眠症状的 MDD 患者中的研究。
尽管存在不一致之处，但八项研究的现有结果表明，包括杏仁核、前额叶皮层和前扣带回皮层以及脑岛在内的几个脑区存在结构和功能紊乱。在突显和默认模式网络的主要枢纽内和之间的异常功能连接可能为 MDD 和失眠之间的联系提供新的见解，这需要进一步评估。
本文综述的研究数量有限。评估失眠和抑郁的结构和功能神经机制的应用方法各不相同。
神经影像学方法证明了 MDD 和失眠之间存在重叠的潜在神经机制。未来的研究可能有助于更好地理解它们的病理生理学，从而开发出针对性的治疗方法。
