The prevalence of autism diagnoses in the US has more than doubled since 2002, according to Spectrum News , an independent news source with a focus on autism research founded by the Simons Foundation Autism Research Initiative (SFARI).
This increase in diagnosis is relatively equal across socioeconomic groups, but the overall total percentages of children diagnosed with autism is still significantly greater for upper class, male and white children.
“White children are about 19 percent more likely than Black children and 65 percent more likely than Hispanic children to be diagnosed with autism,” the article from Spectrum News said. According to a 2017 study by the American Journal of Public Health, socioeconomic factors cannot fully explain the disparity in diagnosis across racial and economic groups.
“Everything is a little bit more complicated than we thought,” Maureen Durkin, lead researcher and professor and interim chair of population health sciences at the University of Wisconsin-Madison, told Spectrum News. “We’ve been trying to understand the racial and ethnic difference in prevalence, and it isn’t so simple as that it’s explained by social class.”
Socioeconomic status, and resultant access to better healthcare and schools, does not account for the overwhelming majority of autism diagnoses being given to white boys. When a 2014 study  by the Centers for Disease Control (CDC) adjusted the data for children diagnosed with autism between 2002 and 2014, the differences across racial and ethnic groups remained prominent.
The differences in diagnosis rates also does not have a root in biological prevalence of the condition. According to the National Institute of Health , there are not any biomarkers for Autism definitive enough to be used to diagnose the disorder. Rather, a diagnosis of autism is made subjectively, based on the child’s reported behavior and how it is evaluated by parents and doctors.
This means that every child in the United States—regardless of race, class or sex—should have approximately the same chance of being autistic, and that most disparity is created during the diagnostic process. However, the numbers of undiagnosed autistic children of color is unknown because the numbers of children who never sought a diagnosis cannot be measured. The issue is as much a lack of data as a problem within the data available.
A 2006 study by the CDC  attempted to address the issue by focusing on something quantifiable: misdiagnosis. In a sample of 406 Medicaid-eligible autistic children, only 43.8 percent were initially given the correct diagnosis, as opposed to a separate diagnosis or none at all. When the initial diagnoses of autistic children are divided by ethnic group, the study found that when compared to white children, African American autistic children were 2.6 times less likely to receive the correct diagnosis on their first specialty care visit and 3 times as likely to be given the wrong diagnosis overall.
In other words, white autistic children were more likely to be diagnosed and their first diagnosis was more likely to be correct. Black autistic children were less likely to get any diagnosis, and if they did get one at all it was more likely to be the wrong one.
Even among all the children who were initially misdiagnosed, the most likely type of misdiagnosis varies based on race and ethnic group. The most common misdiagnosis overall for the children in the study was ADHD. However, according to the CDC study African American children were “5.1 times more likely than white children to receive a diagnosis of adjustment disorder than of ADHD, and 2.4 times more likely to receive a diagnosis of conduct disorder than of ADHD.”
This is important because Autism and ADHD have many overlapping symptoms and both are categorized as developmental disorders in the current Diagnostic and Statistical Manual of Mental Disorders (DSM 5), the diagnostic tool published by the American Psychiatric Association (APA). A high rate of misdiagnosis between the conditions is reasonable, and even if a child has one but is given the other diagnosis they are still recognized as having a learning disability. While misdiagnosis is never good and stigma against both conditions does exist, either of these diagnoses can get the child accommodations in school and the symptoms of both are understood to be inherent to the child.
On the other hand, adjustment disorder and conduct disorder are listed under “emotional disturbance” and “Trauma and Stressor Related Disorders” respectively in the DSM 5. Children diagnosed with either condition are treated for behavioral issues rather than a disability. The symptoms of both diagnosis are treated as behavioral problems to be adjusted rather than symptoms of the child’s needs not being met that need further accommodation.
All of the children in the CDC study were autistic. The national disparity in children diagnosed with autism cannot be fully accounted for by socioeconomic disparities or biological markers. The CDC researchers hypothesized that the differences in diagnosis could be due to “variations in parents’ descriptions of symptoms, clinician interpretations and expectations, or symptom presentation.” While the exact reasons behind the racial and ethnic disparity in Autistic children is not definitively known, the implicit bias in many clinicians, who are overwhelmingly  white , may constitute a large part of why there are the gaps and misdiagnoses in line with stereotypical beliefs about Black children.
Ultimately, the fact remains that Black autistic children are more likely to be misdiagnosed, and even among those misdiagnosed they are more likely to be mistakenly labeled in ways that mark them as mentally unstable and prone to violence rather than disabled. Misdiagnosis also deprives children of necessary accommodations and understanding and subjects them to treatment for conditions they do not have.
The national rates of diagnosis are increasing with awareness, Spectrum News said. According to the article, “this suggests that autism awareness and access to services are increasing across racial and ethnic groups, but the prevalence among minority children still lags behind that of white children.” So, better awareness of symptoms and presentation, especially in communities of color, can increase accurate diagnosis rates and help autistic children of color get the accommodations they need.
Ultimately, the disparities that occur during the diagnostic process suggest a need to reform how autism is diagnosed in children of color.