Diagnostic stability in young children at risk for autism spectrum disorder: a baby siblings research consortium study

Abstract

The stability of an ASD diagnosis in this familial-risk sample was high at both 18 and 24 months of age and comparable with previous data from clinic- and community-ascertained samples. However, almost half of the children with ASD outcomes were not identified as being on the spectrum at 24 months and did not receive an ASD diagnosis until 36 months. Thus, longitudinal follow-up is critical for children with early signs of social-communication difficulties, even if they do not meet diagnostic criteria at initial assessment. A public health implication of these data is that screening for ASD may need to be repeated multiple times in the first years of life. These data also suggest that there is a period of early development in which ASD features unfold and emerge but have not yet reached levels supportive of a diagnosis.