Abstract
Due to the development of metagenomics technology allowing for the analysis of the gut microbial genes exhaustively, a growing attention has been paid to the field of the gut microbiota for mental disorder over the last decade. However, a few clinical studies have been conducted to investigate the association between the gut microbiota and depression. In Japan, only one study demonstrated a significant difference in two bacterial counts in the gut in patients with depression compared to healthy subjects. Thus, further research is clearly needed to examine microbiota profiles in depression.
To this aim, we conducted a systematic computerized literature search of MEDLINE, PubMed, EMBASE, PsycINFO and Cochrane library. The reference lists of the identified original articles and reviews were also searched manually for additional studies. Of the initial search of 95 records including nine records through other sources, the title and abstract of 65 studies were reviewed. We finally selected nine studies that examined the characteristics of gut microbiota in patients with depression : six are cross sectional studies and three are conducted with an intervention. I have summarized the current status in the field by using this systematic review.
