Parent-reported Autism Diagnostic Stability and Trajectories in the Longitudinal Study of Australian Children

This study aimed to explore the stability of parent-reported diagnosis of Autism Spectrum Disorder (ASD) and factors influencing the trajectories in two cohorts from the prospective Longitudinal Study of Australian Children (LSAC). Parent-reported ASD diagnosis was collected for children from 6 years of age in a Birth cohort and 10 years of age in a Kinder cohort; allowing for exploration of diagnostic stability at age 6, 8, 10, and 12 years (Birth cohort) and 10, 12, 14, 16 years (Kinder cohort). Children were grouped based on persisting, desisting, inconsistent and late (diagnosis after 6 years-Birth cohort; after 10 years-Kinder) subgroups over four timepoints. Multinomial logistic regression explored predictors of diagnostic trajectories; generalized estimating equations examined trajectories of emotional and behavioral problems. Of 66 Birth cohort children parent-reported to have ASD at age 6, with data at all four time points, 14% did not at 12 years; of 73 Kinder cohort children at age 10 years, 26% no longer had parent-reported ASD at 16 years. Children with late diagnoses showed increasing trajectories of emotional and behavioral problems, while children with persisting or desisting diagnoses showed decreasing trajectories. Between 86% and 74% had a reported ASD diagnosis after 6 years. Findings indicate that children with ASD need services and supports that can adapt to their changing needs, which may be increasing, decreasing or different. This has implications for the provision of services and funding. LAY SUMMARY: This study explored how consistent parent-reported ASD diagnosis is over time in two groups of children from the Longitudinal Study of Australian Children (LSAC). Although up to 26% of children no longer had parent-reported ASD after 6-years follow up, persisting or late trajectories were more common. The outcome of late onset trajectories requires ongoing review. Autism Res 2021, 14: 773-786. © 2021 International Society for Autism Research and Wiley Periodicals LLC.