Abstract
Children who experience environmental adversities are at increased risk of both internalizing and externalizing disorders. Epigenetic mechanisms may regulate the influence of environmental adversities on mental health. We examined the hypothesis that salivary DNA-methylation patterns of pace of biological aging (DunedinPoAm) and inflammation (DNAm-CRP) are socially stratified and associated with mental health in 1,183 children (609 female, age M=13.6y) from the Texas Twin Project. Analyses were preregistered. Participants' DNA-methylation algorithms and psychiatric symptoms differed by socioeconomic contexts and race/ethnicity. Children with more parent-reported internalizing symptoms had higher DunedinPoAm and DNAm-CRP scores, and children with more aggression problems had higher DNAm-CRP. DunedinPoAm partially mediated advantage of White racial identity on internalizing. Similarly, DNAm-CRP partially mediated advantage of higher family socioeconomic contexts and, in a separate model, White racial identity on reduced internalizing symptoms. Children's epigenetic measures of pace of biological aging and inflammation are associated with social inequalities and mental health.