The epigenetics of suicide: The critical impact of environment on epigenetic regulation in suicide

Suicide is a problem resulting from the interaction between several factors. Among these, early-life adversity, characterized by child sexual, physical abuse or parental neglect, is one of the strongest risk factors for depression and suicidal behaviors. While it is clear that child abuse increases the risk for depression and suicide, the mechanisms mediating these effects are still under deep investigation. A growing body of literature suggests that epigenetic mechanisms may be involved in mediating the effects of early-life adversity (ELA) on behavior. In both human and animal models, ELA has been shown to alter DNA methylation in genes regulatory regions which, in turn, has been associated with changes in gene expression and behavioral modifications. However, although epigenetic modifications have been found in several genes, the extent of epigenetic changes induced by ELA is still unknown, and their impact on increasing suicide risk are unclear. This chapter aims at identifying and describing the molecular mechanisms by which ELA induces behavioral changes conferring vulnerability toward mood disorders and suicidal behaviors.