Associations between Caregiver Stress and Language Outcomes in Infants with Autistic and Non-Autistic Siblings
Caregivers of autistic children present with high stress levels, which have been associated with poorer growth and outcomes in a number of developmental domains, including language, in autistic children. However, we did not previously know whether elevated caregiver stress was associated with language development in younger siblings of autistic children, who are at increased (approximately twenty-fold) likelihood of receiving a future diagnosis of autism and/or language impairment as compared to siblings of non-autistic children. The present study, therefore, explored whether and to what degree, as well as the putative mechanisms by which, caregiver stress was linked with later language outcomes of infant siblings of autistic and non-autistic children (Sibs-autism and Sibs-NA). Results of this study indicate that caregiver stress is indirectly related to later child language outcomes through caregiver linguistic input, across both Sibs-autism and Sibs-NA. Specifically, significant indirect effects suggest that caregivers with increased stress may speak less to their infants, resulting in reduced child language outcomes later in life for infants at both elevated and relatively lower, general population-level likelihood for a future diagnosis of autism. Clinical implications of the findings and future directions for research are discussed.