Imaging Genetic and Epigenetic Markers in Mood Disorders

Genetics explain 60–85% and 31–50% of the risk to develop, respectively, bipolar disorder (BD) (1, 2) and major depressive disorder (MDD) (3, 4). Thus, hereditability has emerged as a crucial factor in the pathophysiology of mood disorders. Early genetics studies focused their attention on specific single-nucleotide polymorphism (SNP), preselected on prior evidence for their functional role in coding products that may influence relevant features of the disorders, also known as candidate gene approach. In these studies, we define risk allele, genetic variants associated with the disorder or worse clinical features such as reduced response to therapeutics, early onset, and higher recurrence.