Epigenetics, early adversity and child and adolescent mental health

Epigenetic modifications, such as DNA methylation (DNAm), can help explain how early adversities can engender long-term vulnerability for mental health problems. At present, there is preliminary evidence to support the possibility of epigenetic mediation: environmental factors are reported to influence offspring DNAm, which in turn, associate with child and adolescent psychopathology. However, all analyses have been correlational in nature and, as these studies have focused on children and adolescents, DNAm has been based on peripheral tissue (cord blood, whole blood, buccal cells). Therefore, the extent to which DNAm could represent a causal mechanism (e.g. a surrogate of central nervous system function) or a biomarker (i.e. an indicator of the pathological process leading to disease) is unclear. Thisshort report has two main components. First, two studies are summarised, one a candidate gene study and the other an epigenome-wide association study, in which DNAm was reported to (partially) mediate the link between adversity and child development. Second, there is a discussion of (i) the “tissue issue”, (ii) maximizing the interpretability of candidate gene andepigenome-wide approaches, and (iii) the need for examining DNAm as a potential biomarker for mental health. It is argued that advances within these three areas will make clearer the role of DNA methylation in the link between adversity and child and adolescent mental health