There is often a large time gap between caregivers’ initial concerns and the diagnosis of autism spectrum disorder. The current study aimed to identify factors associated with missed or delayed autism spectrum disorder diagnoses among children in Colorado. In a surveillance-based sample of 8-year-old children with autism spectrum disorder ( N = 572), we examined differences between children who were identified with autism spectrum disorder by a community provider and/or were eligible for special education services under an autism eligibility (documented diagnosis) and children who were first identified with autism spectrum disorder through a systematic record review (newly identified). Compared to documented diagnosis children, newly identified children were more likely to be female, aggressive, and argumentative. They were less likely to have had a developmental regression, sleep abnormalities, or an autism screener or diagnostic measure in their records. Newly identified children also had a poorer quality of information in their records. Furthermore, among documented diagnosis children, variations in clinical presentations were associated with significantly different mean ages at autism spectrum disorder diagnosis; children who showed early delays, motor abnormalities, hyperactivity and attention deficits, and odd responses to sensory stimuli received a diagnosis much earlier than documented diagnosis children with other clinical presentations. Lay abstract Although autism can be reliably diagnosed as early as 2 years of age, many children are not diagnosed with autism until much later. We analyzed data to determine why many of the 8-year-old children who resided in Colorado and were identified as having autism through a review of their health and/or educational records did not have a documented clinical diagnosis of autism and were not eligible for special education services under an autism eligibility. We found that children who did not have a documented clinical diagnosis of autism and were not eligible for special education services under an autism eligibility were more likely to be female, aggressive, and argumentative. They had a poorer quality of information in their records and were less likely to have had a developmental regression, sleep problems, or an autism screener or diagnostic measure in their records. These results suggest that the symptoms characteristic of autism among this group of children may have been attributed to another disorder and that clinicians may be able to recognize autism more readily in children with more functional impairment and those who experience a developmental regression. We also discovered that differences in symptom presentations among children who had a documented clinical diagnosis of autism and/or were eligible for special education services under an autism eligibility were associated with different ages at autism diagnosis.
Cortical surface architecture endophenotype and correlates of clinical diagnosis of autism spectrum disorder