Infant Mental Health Home Visiting and Its Buffering Effect of Methylation on Infants' Socioemotional Health

Background: Infants born to parents with childhood or current adversity are at heightened risk of negative socioemotional outcomes (Bale, 2014; Park et al., 2019). Early and current adversity can interfere with parental capacity to respond accurately to infant cues, especially distress-related ones (Lyons-Ruth et al., 1999), leaving the infant in a heightened alarm state. Recent research has sought to understand how early exposure to stress affects risk for mental health outcomes over the lifetime and across generations (DeSocio, 2018). Methylation of DNA is an epigenetic mechanism thought to be linked to environmental stress and adversity (DeSocio, 2018). Methylation of the NRC31 gene that codes for glucocorticoid receptors is among the most studied. Traditionally, methylation of the NRC31 gene is thought to suppress the expression of GRs, thereby harming the feedback loop that reduces the hypothalamic-pituitary-adrenal (HPA) axis when cortisol levels remain too high for too long (DeSocio, 2018). High cortisol levels are toxic to the developing brain, disrupting the structures regulating behavior and emotions (Bock et al., 2014). Methylation of NRC31 is associated with internalizing behavior in preschoolers (Parade et al., 2016).

Study: Research on interventions that disrupt the intergenerational transmission of the negative effects of adversity is nascent. The Michigan Model of Infant Mental Health Home Visiting (IMH-HV) is a needs-driven dyadic intervention focused on improving the parent-child relationship quality. The current study sought to examine the effect of IMH-HV on the relationship between toddlers’ NRC31 methylation and toddlers’ socioemotional competence and the mediating role of disrupted caregiving behaviors in a randomized controlled trial.

Methods: Participants included a sample of 44 parents and toddlers randomly assigned to receive 12 months of IMH-HV treatment or to a control group. The Atypical Maternal Behavior Instrument for Assessment and Classification System-Brief (AMBIANCE-brief; Cooke et al., 2020) was used to measure caregiver behavior. Toddler socioemotional competence was measured via parental report using the Brief Infant-Toddler Social Emotional Assessment (BITSEA; Briggs-Gowan et al., 2004), a 44-item parent-report measure for children ages 12–35 months. At 12 months post-enrollment, saliva samples were collected from children using Oragene kits (DNA Genotek). Methylation of the exon 1F region of the glucocorticoid receptor, NRC31, was measured via pyrosequencing.

Findings: The overall regression model, including child methylation, treatment, and an interaction term between methylation and treatment predicting child socioemotional competence, was significant, F (3, 40) = 5.94, p = .05, R² = .17. Moderation analysis revealed a significant interaction effect of IMH-HV treatment on the relationship between children’s methylation of NRC31 and their parent-reported socioemotional competence, F (1, 40) = 6.77, p = .013, DR² = .14). Simple slopes revealed that in the absence of treatment, methylation of NRC31 predicts lower socioemotional competence (b = -.37, p = .03). However, this effect is not seen for children in the treatment group (b = .33, p > .1), suggesting that IMH-HV treatment appears to buffer the effect of NRC31 methylation on children’s socioemotional outcomes. Further analyses will be presented, including the possible mediating role of disrupted caregiving behavior.