Depression and anxiety in the postnatal period : an examination of mother-infant interactions and infants' language development

Abstract

Infancy is a time period associated with significant and rapid social-emotional and cognitive development. Environmental influences, particularly the quality of the mother""infant interaction, assist in shaping these early capacities. Maternal factors such as depression and anxiety can have a negative impact on a mother's sensitivity towards her infant and indirectly compromise child developmental outcomes. However, little is known about the impact of depression and anxiety on communicative interactions and language outcomes in young infants. This thesis reports a longitudinal study, which primary objective was to examine the mechanisms through which maternal depression and anxiety influence infant language development via the quantity and quality of mother""infant interactions. The second objective was to evaluate the effectiveness of a video feedback intervention aimed at promoting maternal responsiveness, a construct that captures the quality of early mother""infant interactions. To address these objectives this longitudinal study followed a sample of mother""infant dyads in which the mothers were or were not affected by anxiety and depression symptoms, between the infants' ages of 6 to 18 months. The study included four components that measured the quantity and quality of the mother""infant interactions and infant developmental outcomes between groups and across time. The first component of the longitudinal study involved home recordings examining the quantity of maternal speech input to the infants at 6 and 12 months of age. The second component involved the assessment of infants' lexical abilities at 18 months of age. The third component consisted of assessments of the quality of mother""infant interactions at 9 and 12 months. The final component involved the evaluation of a short intervention aimed at promoting maternal responsiveness within mother""infant interactions. Findings demonstrated that maternal depression and anxiety have an effect on infants' early lexical abilities via both the quantity and quality of mother""infant interactions. These results suggest that variability in mothers' emotional health influences infants' home language experience, the concurrent frequency of vocalisations, and their later vocabulary size and lexical processing efficiency at 18 months. Maternal responsiveness, a measure of the quality of mother""infant interactions, emerged as the strongest predictor of infant vocabulary size.

Date of Award	2019
Original language	English