TUESDAY, Jan. 14, 2020 (HealthDay News) -- Far too many U.S. children with autism are waiting too long for a diagnosis, new research shows, and those delays can greatly affect their quality of life.

About one in every four 8-year-olds assessed in the new study was found to have undiagnosed autism and wasn't receiving autism services. Most of those kids were black or Hispanic, according to the report published online recently in the journal Autism Research.

It's not clear why minority kids, especially, aren't getting the diagnoses and services they need, the investigators noted.

"There may be various reasons for the disparity, from communication or cultural barriers between minority parents and physicians to anxiety about the complicated diagnostic process and fear of stigma," said study co-author Walter Zahorodny. He's an associate professor at Rutgers New Jersey Medical School and director of the New Jersey Autism Study.

"Also, many parents whose children are diagnosed later often attribute their first concerns to a behavioral or medical issue rather than a developmental problem," Zahorodny said in a Rutgers news release.

One autism specialist unconnected to the new study said the findings are concerning.

"Despite the emphasis on identifying and treating autism spectrum disorder [ASD] early on, many grade-school children with ASD were not diagnosed as such nor getting appropriate treatments for ASD in the school setting," said Dr. Andrew Adesman. He's chief of developmental and behavioral pediatrics at Cohen Children's Medical Center of New York in New Hyde Park, N.Y.

In their study, Zahorodny and colleagues tracked data on 266,000 children who were 8 years old in 2014. The researchers wanted to identify kids who had symptoms of autism but weren't yet diagnosed or receiving autism services.

Of the nearly 4,500 children identified as having autism, 25% had not yet been diagnosed. Most of the undiagnosed children were black or Hispanic boys who had difficulties in mental abilities, social skills and activities of daily living, but were not considered disabled, the researchers said.

Adesman noted that, according to the study, there were hints that the undiagnosed youngsters might have an autism spectrum disorder.

"Although the children with undiagnosed ASD were overall milder in severity, and were less likely to have been evaluated prior to age 3, the reality is that the majority of these parents did have developmental concerns about their child prior to age 3," he said.

Overall, the findings suggest that even though there's growing awareness about autism, it's still underdiagnosed.

According to Zahorodny, diagnosis rates could improve by screening all toddlers, preschool and school-age children for the disorder.

He also believes that doctors can bridge communication barriers by using pictures and/or patient navigators to help parents understand the diagnosis process, test results and treatment recommendations.

In addition, Zahorodny suggested that states can improve access to autism care by making insurance companies cover autism services when a child is first deemed to be at risk, instead of waiting for a diagnosis.

More information

The U.S. Centers for Disease Control and Prevention has more on autism.