The microbiota-gut-brain axis and bipolar disorder

In the last few years, researchers are going beyond the conventional theories behind neuropsychiatric diseases, and the role of neuroinflammation is being increasingly recognized. It is known that microbiota plays a key role on human health and that there is a reciprocal communication between brain and gut. Also, it has been proved that altered microbiota can lead to systemic and central inflammation by several ways. For all these reasons, it has been hypothesized that alterations in the gut microbiota and the subsequent malfunction of the microbiota-gut-brain axis (MGBA) may be involved in the pathogenesis of various neuropsychiatric diseases including bipolar disorder. In this chapter, we aim to (1) summarize the different mechanisms by which the gut microbiota may modulate brain functions, (2) expose the consequences of leaky gut and dysbiosis, (3) illustrate the impact of MGBA in bipolar disorder patients and their relatives, and (4) present future therapeutic approaches targeting this axis.