Early Life Adversity and Oxytocinergic Plasticity: A Cross-Level Framework from Human Evidence and Animal Models.

Early life adversity (ELA) is associated with long-lasting alterations in socio-emotional behavior, stress regulation, and psychopathology risk. A growing literature implicates the oxytocinergic system in these outcomes, yet findings across human and animal studies remain highly heterogeneous. This review advances a cross-level model to explain why oxytocinergic findings after early adversity diverge across studies, proposing that this heterogeneity reflects context-dependent recalibration rather than methodological noise or a uniform deficit. We integrate evidence from human studies, preclinical models, and gene-environment research to show that ELA-related oxytocinergic outcomes vary according to adversity dimensions, developmental timing, sex, species, biological compartment, brain region, and genetic or epigenetic susceptibility. Rather than framing ELA as producing a uniform oxytocin deficit, we argue that early adversity can reshape oxytocin signaling at multiple levels, including peripheral release, central receptor expression, epigenetic regulation, neural circuit function, and pharmacological responsivity. This cross-level framework may help explain divergent findings and guide future studies toward dimensional, developmentally informed, and sex-sensitive models of oxytocinergic plasticity after early adversity.