Limited prospective data have examined the effects of adverse childhood experiences (ACEs) on outcomes as early as elementary school, and few studies have explored cortisol and oxytocin as biomarkers for risk and resilience that may predict later life outcomes. The Hair Biomarkers Study (HBS-I) evaluated healthy preschool children (age 9-72 months) using parent surveys and scalp hair to measure cortisol (HCC; ng/mg) and oxytocin concentrations (HOC; ng/mg) via ELISA. Prospective follow-up at elementary school (age 7-12 years) included school attendance, Child Behavior Checklist (CBCL), and health outcomes. The cohort (N = 189) was 62% male, 41% White, and 90% living in a nuclear family. In multivariate negative binomial, linear, and logistic regression models, 1+ versus 0 ACEs at preschool was associated with 57% higher absenteeism in first-grade (95% CI: 1.02, 2.41), 12.3 percentile higher CBCL Total Problems (95% CI: 1.69, 22.89), and 3.7-fold greater odds of medically unexplained symptom(s) (95% CI: 1.12, 12.04). Higher preschool HOC predicted fewer school absences (RR: 0.90; 95% CI: 0.82, 0.98), while higher HCC predicted more sleep problems (OR: 1.49; 95% CI: 1.02, 2.18). Higher parental stress at preschool age predicted internalizing (Est: 1.39; 95% CI: 0.82, 1.95) and externalizing problems (1.17; 95% CI: 0.67, 1.67), and lower child health ratings (OR: 0.92; 95% CI: 0.86, 0.97). Preschool ACEs exposure was consistently associated with poorer outcomes across all 3 domains of academics, behavioral problems, and health. Collaboration among pediatricians, schools, mental health professionals, and community organizations is essential to mitigate ACEs-related long-term sequelae.

The theoretical underpinnings and empirical data supporting oxytocin as a context-dependent biomarker of prosocial affiliation, bonding, attachment, emotional regulation, cognitive development, and the modulation of stress responses are summarized. We propose an interdisciplinary consensus against a backdrop of inconsistencies concerning behavioral and experimental findings for the oxytocinergic system. Current knowledge gaps demonstrating the inability to establish a hierarchy of findings are related to the following: (a) the theory and practice of oxytocinergic therapeutic interventions; (b) identification, characterization, and quantification of functional, mechanistic, and molecular biomarkers and matrices; (c) context- and time-dependent resilience factors associated with mind–brain–body development, (d) measures of intergenerational transmission, and (e) summative indicators of psychopathological co-morbidities. We analyze prospective objective measures of oxytocin against subjective caregiver reports of positive childhood experiences (PCEs, resulting from secure nurturing, established daily routines, pleasurable social interactions, opportunistic and spontaneous play, secure environments), which favor healthy developmental outcomes in preschool children. Few studies prospectively use the painless, noninvasive sampling of risk and resilience biomarker levels to index the health status, emotional regulation, and cognitive development in preschool children. We present the methodology for novel measures of risk (cortisol) and resilience (oxytocin) in human scalp hair. Future studies validating the therapeutic efficacy of oxytocin or the stress-mediating effects of oxytocin on socioemotional regulation and health status should systematically address these gaps.