Abstract The gut–brain axis is a two-way communication system connecting the gastrointestinal tract and the central nervous system through neural, hormonal, and immune pathways. Recent advances in microbiome research have shown that the gut microbiota greatly impacts brain function, behavior, and mental health. This narrative review explores current understanding of how the gut–brain axis operates and its implications for neuropsychiatric disorders such as depression, anxiety, autism spectrum disorder, and Parkinson’s disease. It highlights key mediators of gut–brain communication, including the vagus nerve, microbial metabolites like short-chain fatty acids, neurotransmitters, and inflammatory cytokines. Evidence from both animal and human studies suggests that alterations in gut microbiota, known as dysbiosis, are linked to various mental health conditions. Studies involving probiotics, prebiotics, and dietary interventions show promise in modifying the gut microbiome and enhancing mental health. The review also considers emerging treatments targeting the gut–brain axis, including fecal microbiota transplantation and psychobiotics. However, these approaches are mostly experimental and pose significant safety and ethical challenges that need further study. Understanding this connection offers new opportunities to prevent and treat neuropsychiatric disorders through microbiome-based therapies. Nevertheless, applying current knowledge clinically faces obstacles, including the lack of standardized methods, the need for larger clinical trials, the need for personalized treatments tailored to individual microbiomes, and the heterogeneity of psychiatric diagnoses. This review highlights the transformative potential of gut–brain axis research in shaping how we approach mental health and neurological diseases.
Ahmed Abdulaziz Almohammadi (Thu,) studied this question.