Study: Black Children with Autism Receive Delayed Diagnosis

In terms of prevalence, the combined rate of ASD across the 11 sites was 16.8 per 1,000, or 1 in 54. Prevalence was higher among boys than among girls (4.3 to 1). When examining prevalence among white, non-Hispanic black, and Hispanic children, researchers found that the prevalence was similar between white and non-Hispanic black (hereafter referred to as black) children but was lower among Hispanic children. That is, rates of ASD were similar across white and black children but were lower among Hispanic children. As disparities among age of diagnosis and services between white non-Hispanic and Hispanic children was discussed in a previous post, I will focus the rest of the current post on disparities between white and black children.

Disparities in Age of First Evaluation 

Though the prevalence rates among white and black children were similar, disparities were noted in the age of first evaluation. Among 3,981 children with ASD, 44% were evaluated by age 3. However, the percentage of white children evaluated by age 3 was 45%, the percentage of Hispanic children evaluated by age 3 was 43%, and percentage of black children evaluated by age 3 was 40%. This suggests that although the prevalence of ASD is similar among white and black children, black children are less likely to be evaluated by age 3 compared to their white peers.

Disparities in Age of Diagnosis

Of 3,764 children with an official ASD diagnosis (e.g. those who were evaluated and given a clinical diagnosis), the median age at diagnosis was 51 months (4 years, 3 months). Children with lower cognitive scores (e.g. those more likely to have a co-occurring Intellectual Disability) had a median age at diagnosis of 44 months (3 years, 10 months), whereas those with higher cognitive scores had median age at diagnosis of 57 months (4 years 9 months). Importantly, among those with lower cognitive scores, black children had a median age of diagnosis of 48 months compared to white children at 42 months. The fact that children with lower cognitive scores were diagnosed earlier than those with higher cognitive scores is not surprising, because children with lower cognitive scores are more likely to have obvious developmental delays early in life, and to have more severe symptoms. The fact that black children with lower cognitive scores have a median age of diagnosis of 4 years, compared to their white peers with a median age of diagnosis of 3 years, 6 months, however, is deeply problematic.

Consequences of Disparities 

Although the 6-month difference between 3 years, 6 months and 4 years may seem small, it is a large gap when considering the importance of early intervention. Evidence-based behavioral interventions, such as the Early Start Denver Model (ESDM), were specifically designed for children under 4. A 2020 review of scientific studies using ESDM reported age ranges between .75 years (18 months) to 3.77 years (approximately 3 years, 9 months). By the time black children with ASD and lower cognitive skills are diagnosed (e.g. 48 months), it is too late for them to enroll in one of the most widely studied and successful behavioral interventions. Other research similarly suggests that intervention may be more successful if begun early in life (e.g. Harris & Handlman, 2000; Kasari et al., 2012; Zwaiganbaum et al., 2015).

This report suggests that we have work to do to close the diagnostic age gap between white and black children. Studies like the ones above represent a critical first step, since we as a field cannot hope to solve a problem without finding concrete evidence of it. Now that we have it, it is time to increase access to high-quality screening and diagnostic services for these families.