Abstract
Since decades, there is a change in concept of the gut-brain axis. There is differential increase in evidences focusing on the bidirectional communication between the gut microbiome and the brain. It supports existence of far-reaching model of "gut-brain axis." This axis is attaining more adherence to fields investigating biological and physiological footing of psychiatric, neuro-developmental, age-related, and neurodegenerative disorders. Many factors can change microbiota composition in early life as well as with the increasing age. Stress can affect the microbiota-gut-brain axis at every stages of life. Recent advances have involved the gut microbiota in many conditions including severe mental illness, autism, anxiety, obesity, Parkinson's disease, and Alzheimer's disease. The current studies target on elaborating the underlying mechanisms of microbiota-gut-brain axis and attempt to exemplify intervention and therapeutic strategies for neuropsychiatric disorders.