A new study shows more children in the United States have been diagnosed with a developmental disability than ever before. From 2009-2017, the total percentage went from 16.2 to 17.8%, with much of that increase coming from increased diagnoses of ADHD and autism spectrum disorder (ASD).

Before you let these numbers alarm you, however, you should know that experts think this is actually a very good thing.

The study was done by researchers at the Centers for Disease Control and Prevention and published in the journal Pediatrics this week. It looked at data collected from a national survey on about 90,000 children ages 3-17, asking parents whether their children had been diagnosed with any of 10 possible developmental disabilities. It found that ADHD went up from 8.5% to 9.5%, autism spectrum disorder rose from 1.1% to 2.5%, and intellectual disability rose from 0.9% to 1.2%.

A similar report published in 2011 found that developmental disabilities rose from 12.84% in 1997 to 15.04% in 2008. That means there's been a 38% increase in these diagnoses over the past 22 years. Boys were most likely to be diagnosed than girls. Children with public health insurance and those with family incomes at or above 200% of the poverty level were also more likely to receive diagnoses. Hispanic children were less likely to be diagnosed, though that population saw the highest increase over the past 10 years.

"Measuring the prevalence of developmental disabilities in the population helps to gauge the adequacy of available services and interventions," lead author Benjamin Zablotsky said in a video abstract of the study.

Zablotsky also gave a couple of caveats about the results. First, it's self-reported, relying on parents' information about their children. Second, as he pointed out to HealthDay News, the wording of the survey (an outside survey the authors had no control over) had changed over time, which may have messed with the numbers. Most importantly, these statistics reflect how many kids were diagnosed, not how many have a disability.

That last part is why Maureen Durkin, professor of population health sciences and pediatrics at the University of Wisconsin-Madison, wrote an editorial in Pediatrics wondering if these numbers are a sign of progress. Increased diagnoses means there's been an increase in awareness of these disabilities, along with more screening for them.

Since 2007, the American Academy of Pediatrics has recommended that all children be screened for ASD at 18 and 24 months. Early diagnoses and early intervention can help improve children's development over time, the AAP states. That's not to say that there hasn't also been an increase in the number of children with these disabilities. People are having kids later in life than they used to, and older parental age is a risk factor for autism, so that would account for a rise. This may also be a side effect of advances in neonatal medicine.

"Similar trends have been reported from other countries and are likely a consequence of improvements in child survival, especially improvements that extend to children at high risk of disability due to risk factors such as preterm birth, brain trauma, and congenital conditions such as Down syndrome," Durkin added.

Regardless of why the numbers are the way they are, this latest study is something policymakers, educators, and doctors all need to keep in mind. Special needs kids aren't a rarity in the world but a significant part of our population deserving of resources and care.

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