Epigenetic influences on affect and emotion regulation: Insights from the oxytocin system.

Epigenetic mechanisms provide a bridge linking early social experience to lifelong trajectories of health and wellbeing. This chapter reviews evidence that epigenetic regulation of the oxytocin system, particularly DNA methylation of the oxytocin receptor gene (OXTR), serves as a key molecular mediator of socio-emotional development. We synthesize findings from humans and socially monogamous prairie voles demonstrating that the quality of parental caregiving influences OXTR DNA methylation, alters gene expression and circuitry in amygdala-prefrontal networks, and predicts individual differences in social cognition, stress reactivity, and vulnerability to psychopathology. Imaging-epigenetic studies further reveal that peripheral OXTR methylation in blood and saliva correlates with functional brain activation and connectivity in brain systems governing salience/attention and inhibitory self-control from infancy through adulthood. We call attention to emerging work on hydroxymethylation, alternative OXTR transcripts, and epigenetic clocks, emphasizing their potential to refine biomarkers of risk and resilience. Adopting a dynamic system perspective, we propose a developmental model of emotion in which early-life care calibrates gene expression to balance bioenergetic demands against social resources. Finally, we outline methodologic priorities, including longitudinal, multitissue sampling and epigenetic editing, that can accelerate translation of oxytocin-based interventions for affective disorders. Collectively, these insights position OXTR as a tractable target for personalized prevention and treatment strategies in psychiatry.