The role of the gut microbiota in neuropsychiatric disorders and therapy

The vast microbial community residing in the gut is known as the gut microbiota (GM). Alterations in the compositional equilibrium of the GM, a phenomenon termed GM dysbiosis, have been increasingly associated with the pathogenesis of various diseases, particularly neuropsychiatric disorders. The microbiota-gut-brain axis (MGBA) serves as a bidirectional communication system that connects the gut to the brain. Notably, several prevalent neuropsychiatric disorders, including depression, Alzheimer's disease (AD), and Parkinson's disease (PD), collectively affect over one billion individuals globally. Emerging scientific evidence has consistently demonstrated the presence of GM dysbiosis in various neuropsychiatric disorders, suggesting a potential etiological role of GM in these conditions through MGBA-mediated mechanisms. In this comprehensive review, we systematically discussed the GM and MGBA, and presented evidence from both animal and human studies that highlighted the significance of GM in the occurrence and development of neuropsychiatric disorders. Subsequently, we emphasized the potential impact of GM and its metabolites on neuropsychiatric disorders. Next, we summarized the drugs used to treat diseases by regulating the GM. Finally, we proposed strategies to ameliorate the malignant progression of neuropsychiatric disorders by manipulating the composition of the GM. These strategies encompass the application of probiotics, prebiotics and synbiotics, postbiotics, fecal microbiota transplantation (FMT), and dietary interventions. Collectively, targeted GM therapy has the potential to be an effective treatment for neuropsychiatric disorders.