Identifying Predictors of Diagnostic Instability of Autism Spectrum Disorder and Global Developmental Delay In Toddlers

Although Autism Spectrum Disorder (ASD) is considered to be a lifelong condition, some toddlers experience diagnostic instability over time. In particular, some toddlers’ diagnosis changes between ASD and Global Developmental Delay (GDD). However, little is known about the subset of children who change diagnosis. In a total of 424 toddlers who either maintained or changed diagnosis, the current study identified predictors of change in diagnosis and severity in those who change from ASD to non-ASD (ASD-NON), ASD to GDD (ASD-GDD), non-ASD to ASD (NON-ASD), and GDD to ASD (GDD-ASD) between two years old and four years old. Initial ASD symptom severity and participation in intervention services were predictive of all transitions. Additionally, receptive language predicted ASDNON transition and socioeconomic status predicted ASD-GDD transition. Implications for informing prognosis of children, identifying targets of intervention, refining of screening and diagnostic measures, and measuring change in severity regardless of categorical change are discussed. INDEX WORDS: Diagnostic stability, Early diagnosis, Child development, Developmental delay, Symptom severity, Intervention IDENTIFYING PREDICTORS OF DIAGNOSTIC INSTABILITY OF AUTISM SPECTRUM DISORDER AND GLOBAL DEVELOPMENTAL DELAY IN TODDLERS