A review of 42 studies spanning 22 years provides insights into the family and community dynamics that encourage – or hinder – earlier diagnosis of autism spectrum disorder.
“Despite our being able to reliably diagnose autism as early as 24 months, many children are still going undiagnosed until grade school,” says Amy Daniels, Ph.D., Autism Speaks assistant director of public health research. “By recognizing and addressing the factors that delay diagnosis, we ensure that many more children get the quality early intervention that we know can transform lives.”
Dr. Daniels co-authored the research review with David Mandell, Ph.D., of the University of Pennsylvania Perelman School of Medicine. It appears online this week in the journal Autism.
Overall they saw an encouraging trend toward earlier diagnosis over the last 20 years. Average age of diagnosis dropped from more than 10 years to under 4 years of age. Within these averages, however, they found persistent disparities.
Confusion among parents and providers
For instance, several studies found that children with other medical and psychological conditions tended to be diagnosed later than average. Such conditions included hearing impairment and attention deficit disorder. Similarly, two studies associated delayed diagnosis with parents mistaking autism symptoms for other behavioral problems such as being “stubborn” or “spoiled.”
Conversely, several studies associated earlier diagnosis with parent concern about their child’s social skills or unusual behaviors such as repetition or fixations.
As expected, the investigators found that more severely affected children tended to be diagnosed earlier than those with milder disabilities. So did children experiencing regression, or loss of developmental skills, after the first or second year.
Mixed results on ethnicity, income and education
Several studies looked at ethnic differences in age of diagnosis. Some found no association. Others found later diagnosis among African American or Hispanic communities.
Studies were likewise mixed on the effect of family income and parent education. Some associated earlier diagnosis with higher income or education level. Others found little or no difference. Overall, the studies found no gap between boys and girls.
Access to services crucial
In general, children living in rural communities tended to be diagnosed later than those in suburbs or cities. The suggestion – that access to services is crucial – was supported by a study that associated early diagnosis with living areas with relatively more psychiatrists and neurologists.
Of the 42 studies, 19 were based in the United States, 3 in Canada, 15 in Europe (including the United Kingdom) and the rest in other countries.
Autism Speaks tackles earlier access to care
"As this research makes clear, understanding what is behind disparities in early diagnosis is far more complex than any single factor such as level of awareness, race or socioeconomic status," Dr. Daniels says. "Multiple factors are at play, and this is why our Early Access to Care initiative takes a multifaceted approach."
Autism Speaks Early Access to Care initiative is dedicated to closing disparities in autism diagnosis and early intervention. “Pinpointing the factors behind the gaps is just the beginning,” Dr. Daniels says. “This review’s findings can help us focus both our current outreach efforts and future research aimed at developing practical and effective solutions.”
Read more about Autism Speaks Early Access to Care initiative here and more about and from Dr. Daniels here. Dr. Mandell is the recipient of several Autism Speaks research grants focused on improving understanding of autism’s impact on families and society and the financial and practical benefits of improved services. Read more about Dr. Mandell’s research and insights here.