How Preconceived Autism Assumptions May Have Led To Years Of Underdiagnosis

Autism spectrum disorder (ASD) is a developmental disorder characterized by neurodivergence, reports Forbes Health. According to the U.S. Centers for Disease Control and Prevention (CDC), differences in brain function can often make socializing and communication difficult for those with autism. Individuals with the condition may also exhibit certain behaviors, such as trouble making eye contact, repetition of specific words or phrases, distress in response to changed routines, or a fixation on certain subjects or interests, amongst other symptoms.

Because the disorder can present with a wide range of varied symptoms, ASD is often underdiagnosed, particularly in girls and women, reports Autism Speaks. Now, a new study published by the American Academy of Pediatrics has identified another potential factor contributing to the underdiagnosis of autism. The research challenged preconceived notions regarding the link between autism and intellectual disability (ID), demonstrating a greater increase in diagnostic rates of autism among children without intellectual disabilities over the course of 16 years. 

Researchers collected data from 8-year-old children between the year 2000 to 2016 living in the New York-New Jersey Metropolitan Area. Autism spectrum disorder was identified in 4661 children, nearly 60% of which did not have an intellectual disability.

As per the study, increases in autism diagnoses among children with intellectual disability was found to have increased by 200% over the course of the sixteen-year period. However, the research also demonstrated that prevalence rates for ASD grew by 500% in children without intellectual disability during the same time period. The study team cited a growing understanding of ASD among the medical community as one possible factor contributing to the rise in prevalence rates.

The research also revealed disparities in ASD prevalence rates in relation to socioeconomic status and race, particularly amongst Black children and Hispanic children. In comparison to white children, rates of ASD without a co-occurring intellectual disability among Black children were found to be 30% lower. Rates of ASD without a co-occurring intellectual disability were also found to be lower amongst those in underserved communities by as much as 80% compared to children living in affluent communities. Such findings indicate an underdiagnosis of autism amongst various sociodemographic groups.

Overall, 2 out of 3 children identified with autism in the study did not have intellectual disability. As a result of their findings, the study team highlighted the need for universal ASD screenings during regular pediatric check-up appointments for all children. As written in the research, the study authors note, "Pediatricians are in an ideal position to address diagnostic inequalities."