Early-onset chronic stress does not heal naturally, and its effects appear to exacerbate over time, with trauma-exposed children presenting a more comorbid, chronic, and externalizing profile as they grow older. Our findings demonstrate that responses to trauma are dynamic and variable and pinpoint age-specific effects of maternal and child factors on risk and resilience trajectories. Results highlight the importance of conducting long-term follow-up studies and constructing individually tailored early interventions following trauma exposure.

Our findings, the first to measure immune and affiliation biomarkers in mothers and children, detail their unique and joint effects on children's anxiety in response to stress; highlight the relations between chronic stress, immune activation, and anxiety in children; and describe how processes of biobehavioral synchrony shape children's long-term adaptation.

While chronic early stress increases child susceptibility to psychopathology, risk and resilience trajectories are shaped by maternal social influences whose role requires much further research in longitudinal studies. We examined the social transmission of risk by assessing paths leading from war-exposure to child symptoms as mediated by 3 sources of maternal social influence; stress physiology, synchronous parenting, and psychiatric disorder. Mothers and children living in a zone of continuous war were assessed in early childhood (1.5-5 years) and the current study revisited families in late (9-11years) childhood (N = 177; N = 101 war-exposed; N = 76 controls). At both time-points, maternal and child's salivary cortisol (SC), social behavior, and externalizing and internalizing symptoms were assessed. In late childhood, hair cortisol concentrations (HCC) were also measured and mother and child underwent psychiatric diagnosis. The social transmission model was tested against 2 alternative models; 1 proposing direct impact of war on children without maternal mediation, the other predicting late-childhood symptoms from early childhood variables, not change trajectories. Path analysis controlling for early childhood variables supported our conceptual model. Whereas maternal psychopathology was directly linked with child symptoms, defining direct mediation, the impact of maternal stress hormones was indirect and passed through stress contagion mechanisms involving coupling between maternal and child's HCC and SC. Similarly, maternal synchrony linked with child social engagement as the pathway to reduced symptomatology. Findings underscore the critical role of maternal stress physiology, attuned behavior, and well-being in shaping child psychopathology amid adversity and specify direct and indirect paths by which mothers stand between war and the child. (PsycINFO Database Record