Maternal depressive symptoms (MDS) in the postnatal period may impact children’s later development through poorer quality parent-child interactions. The current study tested a specific pathway from MDS (child age 9 months) to child receptive vocabulary (4 ½ years) through both self-reported and observed parent-child verbal interactions (at both 2 and 4 ½ years). Participants (n = 4,432) were part of a large, diverse, contemporary pre-birth national cohort study: Growing Up in New Zealand. Results indicated a direct association between greater MDS at 9 months and poorer receptive vocabulary at age 4 ½ years. There was support for an indirect pathway through self-reported parent-child verbal interactions at 2 years and through observed parent-child verbal interactions at 4 ½ years. A moderated mediation effect was also found: the indirect effect of MDS on child vocabulary through observed verbal interaction was supported for families living in areas of greater socioeconomic deprivation. Overall, findings support the potential role of parent-child verbal interactions as a mechanism for the influence of MDS on later child language development. This pathway may be particularly important for families experiencing socioeconomic adversity, suggesting that effective and appropriate supportive parenting interventions be preferentially targeted to reduce inequities in child language outcomes.
