Revisiting inflammation in bipolar disorder.

Bipolar disorder (BD) has been associated with immune changes, and yet their underlying mechanisms are still not fully understood. Here, we review the current state of the field, concerning the inflammatory alterations observed in the periphery and in the central nervous system, followed by a discussion of potential underlying mechanisms. We focus mainly on recently proposed mechanisms including the role of the gut-brain axis, the release of damage-associated molecular patterns (DAMPs), and the genetic and epigenetic mechanisms. BD immunology is an evolving field and current studies indicate this disease is more than a brain disorder, and it can be conceptualized as a multi-system condition.