Intestinal flora and depressive disorders: exploration and prospect of microbial-gut-brain axis

Abstract

This paper examines the correlation between depressive disorders and intestinal flora. Depression is a common affective disorder characterized by low mood, loss of interest, anhedonia, high incidence, high recurrence rate, high disability rate, and high medical costs. The incidence and harmfulness of depressive disorder are gradually increasing, and its etiology is complex and diverse, among which the abnormal intestinal flora is considered to be one of the causes of depressive disorder. This article reviews the results of several studies that found intestinal flora imbalance in depressed patients, including changes in the type and quantity of flora and changes in metabolic pathways. In addition, antibiotic and probiotic treatments have also been shown to be effective in alleviating depressive symptoms, further indicating the importance of intestinal flora disturbances in the pathogenesis of depression. We also explored the relationship between intestinal flora and the pathogenesis of depressive disorders. Through neuro-immuno-endocrine-metabolic pathways, intestinal flora can affect the function of the central nervous system, cause changes in the host’s mental behavior, and lead to or aggravate depressive symptoms. Overall, this study not only found differences in the intestinal flora of patients with depressive disorders but also revealed the potential role of intestinal flora in the pathogenesis. Importantly, this provides a new theoretical basis for further clarifying the pathogenesis of depressive disorders and formulating diagnosis and treatment strategies.

Keywords

depressive disorders / intestinal flora / microbial-gut-brain axis / inflammatory response / neuro-modulation / therapeutic strategies