Epigenetic mechanisms of bipolar disorder

Abstract Bipolar disorder (BD) is a severe, chronic, and multifactorial psychiatric disorder thought to result from an interaction between genetic susceptibility factors and environmental triggers. Part of BD’s heritability might be accounted for by epigenetic mechanisms, which mainly include DNA methylation, histone modifications, chromatin remodeling, and the actions of noncoding RNAs that can modulate gene expression in response to the environment. Epigenetic modifications, described as hereditary but potentially reversible alterations, have been consistently implicated in the pathogenesis of BD, with several studies suggesting that epigenetic alterations may alter the regulation of gene expression in BD, with a great potential use both for discovering disease biomarkers and for therapeutic interventions. This chapter aims to review evidence of the potential key role of epigenetic alterations in the pathophysiology of BD.