Maternal Linguistic Input to Infants Born to Mothers With and Without Postpartum Psychosis and Infant Language Skills: A Preliminary Study

Purpose: This preliminary study investigated maternal linguistic input (MLI) to infants born to mothers with and without postpartum psychosis (PPP), infant language skills, and the impact of MLI on infant language skills. Method: This is a cross-sectional case–control study from South India. The study included 14 mother–infant dyads, with seven dyads each in the PPP group, M age of infant ( SD ) = 8.44 (1.93) months, and the no-PPP group, M age of infant ( SD ) = 8.14 (1.8) months. MLI was assessed through video recordings of mother–infant interactions, focusing on both quantity (total number of words) and quality (type of words, type–token ratio, length of utterance, and types of maternal verbal responsiveness to infant vocalizations). Infant language skills were assessed between 6 and 12 months of infants' age using two parent interview measures: (a) Receptive–Expressive Emergent Language Test–Third Edition and (b) MacArthur–Bates Communicative Development Inventories, Words and Gestures. These measures were administered in languages spoken by the families, such as Kannada, Tamil, Malayalam, and Hindi. Results: Findings indicated that mothers with PPP provided significantly fewer total words and word types, shorter length of utterances, fewer verbal responsiveness to infant vocalizations, and a significantly higher number of no verbal responses to infant vocalizations when compared to mothers without PPP. No significant differences were observed in infant receptive and expressive language skills between the groups. Overall, strong positive correlations were observed between maternal responsiveness to infant vocalizations and expressive language skills as well as between no verbal responses to infant vocalizations and receptive vocabulary counts. Conclusions: The study highlights that there exist differences in the patterns of MLI in mothers with and without PPP. However, further research is needed with larger samples and longitudinal designs to explore the long-term impact of PPP on infant language development.