Child and adolescent internalizing and externalizing traits, and epigenetic summary scores: A scoping review

To better understand the relationship between DNA methylation summary measures and childhood behavioral and emotional problems, this scoping review synthesizes current research on the associations between DNA methylation and internalizing or externalizing traits or behaviors in children and adolescents. By identifying which psychological phenotypes are most consistently linked to DNA methylation summary measures and contextualizing research practices, this review highlights key methodological trends and gaps in the literature. Future research should include diverse and representative samples to enhance the generalizability and robustness of findings. Careful control for genetic ancestry, potential confounders, and adoption of standardized methodologies are important for improving the precision and interpretability of results. Additionally, a comprehensive examination of literature employing alternative DNA methylation methodologies, including epigenome-wide studies and pathway-based analytical approaches oriented toward mechanistic investigation, would afford greater insight into the interplay between DNAm and internalizing and externalizing symptomatology.