抑郁症是一种常见的精神疾病，通常与性别、遗传、环境或心理原因有关。肠道菌群可参与人体的众多生理调节，对情绪状态和行为认知方面发挥重要作用。健康的肠道微生物群主要以拟杆菌门和厚壁菌门为主要优势菌门，而抑郁症患者的肠道微生物丰富度和多样性较正常人相比显著降低。研究发现肠道微生物群通过神经、免疫和代谢途径直接或间接与大脑进行双向沟通，肠道菌群变化与抑郁症之间存在明显的相关性。因此，保持健康的肠道微生物群对大脑健康极其重要。本文主要基于肠-脑轴探讨抑郁症的可能发病机制，分别从肠道菌群影响单胺类神经递质的产生、改变神经系统可塑性、诱使炎症因子水平变化以及导致下丘脑-垂体-肾上腺轴功能紊乱等4个方面对抑郁症的作用进行讨论。此外，本文还总结了几种调节肠道菌群干预抑郁症的可能途径，以期为治疗抑郁症提供新的思路。

Depression is a common mental illness that is often linked to gender, genetic, environmental or psychological causes. Gut microbiota plays an important role in emotional state and behavioral cognition by participating in many physiological regulation of the human body. Bacteroidetes and Firmicutes are the dominant phyla in healthy gut microbiota, while the richness and diversity of gut microbiota in patients with depression are significantly lower than those in healthy people. Studies have found that the gut microbiota communicates directly or indirectly with the brain through neural, immune and metabolic pathways, and there is a significant correlation between the changes of gut microbiota and depression. Therefore, maintaining a healthy gut microbiome is extremely important for brain health. In this review,,based on the gut-brain axis to explore the possible pathogenesis of depression, respectively from the gut microbiota affect single amine neurotransmitter production, change the nervous system plasticity and inflammation factor level change and lead to the hypothalamus-pituitary-adrenal (HPA) axis dysfunction such as four aspects to the discussion of the role of depression. In addition, this paper summarizes several possible ways to regulate gut microbiota to intervene depression, in order to provide new ideas for the treatment of depression.