Epigenetics in bipolar disorder: a critical review of the literature

Psychiatr Genet. 2021 Feb 1;31(1):1-12. doi: 10.1097/YPG.0000000000000267.


Introduction: Bipolar disorder (BD) is a chronic, disabling disease characterised by alternate mood episodes, switching through depressive and manic/hypomanic phases. Mood stabilizers, in particular lithium salts, constitute the cornerstone of the treatment in the acute phase as well as for the prevention of recurrences. The pathophysiology of BD and the mechanisms of action of mood stabilizers remain largely unknown but several pieces of evidence point to gene x environment interactions. Epigenetics, defined as the regulation of gene expression without genetic changes, could be the molecular substrate of these interactions. In this literature review, we summarize the main epigenetic findings associated with BD and response to mood stabilizers.

Methods: We searched PubMed, and Embase databases and classified the articles depending on the epigenetic mechanisms (DNA methylation, histone modifications and non-coding RNAs).

Results: We present the different epigenetic modifications associated with BD or with mood-stabilizers. The major reported mechanisms were DNA methylation, histone methylation and acetylation, and non-coding RNAs. Overall, the assessments are poorly harmonized and the results are more limited than in other psychiatric disorders (e.g. schizophrenia). However, the nature of BD and its treatment offer excellent opportunities for epigenetic research: clear impact of environmental factors, clinical variation between manic or depressive episodes resulting in possible identification of state and traits biomarkers, documented impact of mood-stabilizers on the epigenome.

Conclusion: Epigenetic is a growing and promising field in BD that may shed light on its pathophysiology or be useful as biomarkers of response to mood-stabilizer.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adult Survivors of Child Adverse Events / psychology
  • Affect / drug effects
  • Bipolar Disorder / drug therapy
  • Bipolar Disorder / epidemiology
  • Bipolar Disorder / genetics*
  • DNA Methylation
  • Epidemiologic Research Design
  • Epigenesis, Genetic*
  • Female
  • Gene-Environment Interaction
  • Genetic Association Studies
  • Histone Code
  • Humans
  • Male
  • Organ Specificity
  • Psychotropic Drugs / pharmacology
  • Psychotropic Drugs / therapeutic use
  • RNA, Untranslated / genetics


  • Psychotropic Drugs
  • RNA, Untranslated