The prevalence of autism has risen over the past few decades, a finding established by multiple methods of assessing prevalence. New analyses of a national survey emphasize this trend—estimating a rate of 2.5 percent. They also call attention to the barriers that families face in trying to access services and treatment for children with the condition.
“Nearly a third of children with autism aren’t receiving treatment,” says Wei Bao, the lead author of one analysis and an epidemiologist at the University of Iowa. “Autism is a condition with a lifetime impact, so we want to see children receive appropriate treatment, because it will benefit their lifetime health.”
Two research teams recently mined the 2016 National Survey of Children’s Health for insights on autism prevalence and treatment. The survey encompassed 43,000 children across the United States; parents of those children reported whether a mental health professional had ever told them their child had autism. Both papers—one published in Pediatrics and one published in JAMA Pediatrics—reported that based on parents’ responses, 2.5 percent of U.S. children age 3 to 17 have an autism diagnosis.
The Iowa team also found that the diagnosis rates varied greatly by state. Texas had the lowest prevalence (1.54 percent) while Florida had the highest (4.88 percent). These numbers should be interpreted with caution, Bao says, because the number of respondents for each state were just a fraction of the national total. Still, some states struggle while others succeed at providing care, says David Mandell, the director of the University of Pennsylvania’s Center for Mental Health Policy and Services, who was not involved with the research. Exploring what accounts for the variability is an important question to answer, he says.
The scientists reported that 30 percent of children with an autism diagnosis have not received treatment. Of those who did, 43 percent obtained behavioral treatment, 7 percent were prescribed medication, and 20 percent received both. However, parents may overlook certain treatments when responding to the survey, such as services delivered through the education system, which could make the treatment rate an underestimate, Mandell notes.
The other research team, a collaboration of individuals from multiple federal and academic institutions, explored the experiences of families as they accessed treatment. Parents of children with autism were twice as likely to usually or always experience frustration when attempting to access services compared to parents of children with other emotional or behavioral conditions, such as anxiety, ADHD, and intellectual disability. Autism encompasses a diverse array of symptoms that require different therapies, from behavioral treatment and mental health care to physical therapy and speech therapy, says Michael Kogan, the lead author of the report and the director of the Office of Epidemiology and Research at the Health Resources and Services Administration. “These families face unique challenges,” Kogan says. “It’s hard to achieve coordinated medical care.”
The snapshot produced by the survey has serious limitations, according to Mandell. Surveying parents about their children is less reliable than the approach taken by the Centers for Disease Control and Prevention (CDC), which reviews the medical and educational records of the 8-year-olds it monitors. The CDC also investigates autism alone, whereas the survey format embeds questions about autism within a broader, time-consuming assessment. Survey results also may be biased by parents’ initial choice to participate or not, says Maureen Durkin, a professor of population health sciences and pediatrics at the University of Wisconsin, who was not involved with the research. Parents of children with autism and other disorders may be more motivated to respond than parents of undiagnosed children.
The CDC currently estimates that the prevalence of autism is 1.7 percent. The discrepancy between 1.7 percent and 2.5 percent signal that one of the two estimates is incorrect, Mandell says. Of the two, he believes the CDC’s estimate is closer to the true prevalence.
Despite these limitations, CDC reports also show that rates of autism are rising. In 2002, the first year for which the CDC has available prevalence data, the estimate was 1 in 150. The number jumped to 1 in 125 in 2004. The most recent report places the prevalence at 1 in 59.
Many elements have converged to produce this increase. In 1990, the federal government designated autism as a special education category, prompting states to begin counting children with autism and providing services. In 1994, the definition of autism expanded to include a broader spectrum of cases when Asperger’s syndrome was added to the Diagnostic and Statistical Manual of Mental Disorders. The American Academy of Pediatrics issued a recommendation in 2006 for universal developmental screening at 9, 18, and 30 months. And awareness among clinicians, educators, and families has continued to grow.
“In the 1980s, when I first did my training, we were told that autism was extremely rare, and a pediatrician might never have a patient with autism,” Durkin recalls. “Now pediatricians are taught a lot about autism and we advocate developmental screening for all children.”
These changes capture how the medical community has cast a wider net to identify and treat the condition. Yet biological forces likely also contribute to autism’s rise. Older parental age, and especially older paternal age, is a major risk factor for developing the condition, Durkin says, and parents are having children later in life.
Babies who are born prematurely are also at an elevated risk for developing autism. Modern technologies have allowed more premature babies to survive, likely leading to more children with autism. These clues explain a small portion of the rise but cannot account for the entire change, Durkin says.
As the medical community strives to identify every child with autism, Durkin believes that society stands to benefit not just from developing treatments but from transforming the way autism is perceived. Cultivating greater acceptance toward people who can be considered disabled, and providing more workplace supports, for example, could help those with autism to flourish. “If we’re labeling more children as having autism, then we should also aim to make a more inclusive society,” Durkin says.