Diagnosis Differences

Diagnosis for many children with autism spectrum disorder (ASD) comes late, delaying early intervention, and jeopardizing long-term developmental outcomes. ASD is most often diagnosed by specialized clinicians, but its earliest signs are often picked up by teachers at school, with referrals to school psychologists who may be using different tools to determine ASD among students than specialists.

Medically, ASD is classified using the Diagnostic and Statistical Manual of Mental Disorders (DSM–5). The DSM-5 is considered a “best practice” diagnostic instrument. Its comprehensive evaluation observes deficits in all areas of development, including social, emotional, and communicative behaviors. The DSM-5 also includes a parent interview to help practitioners gauge the child’s past and current behavior.

Alternatively, schools are not required to use the DSM-5 to diagnose students with ASD. Instead, they follow federal guidelines. The federal definition only stipulates communicative and social issues that affect school performance so as to qualify children for special services under the Individuals with Disabilities Education Act (IDEA). Updated in 2004, IDEA requires public schools to provide free specialized education for students with disabilities. These changes led to a sudden increase in ASD diagnosis. In 2002, 1 in 150 children were identified with ASD compared to 1 in 68 in 2010. Individual states can modify their criteria as long as the standards fall within the federal guideline. This means that schools can choose any tool from an array of assessments to evaluate students for ASD.

This disparity between medical settings and schools raises concern that individual differences in autism spectrum disorder symptoms may become lost in the diagnostic chasm.

With no specific requirement, school diagnostic measures for ASD vary greatly by state. A national study found that less than 25% of school psychologists used a comprehensive, evidence-based assessment (like the DSM-5), choosing instead ASD screening measurements that are less thorough. This disparity between medical settings and schools raises concern that individual differences in ASD symptoms may become lost in the diagnostic chasm.

The Hammill Institute on Disabilities conducted a study to evaluate whether children diagnosed in medical or educational settings exhibit differences in ASD symptoms. Parents and caregivers of children with ASD completed questions about where their child was diagnosed (medical or educational setting), how severe their child’s symptoms were, how well their child could perform daily activities, level of independence, and social/behavioral challenges. Participants were residents of Oregon, one of 34 states that do not employ DSM-5 criteria for school diagnosis.

The study found that children identified only by their school had less severe symptoms of ASD than those diagnosed by medical professionals. Interestingly, caregiver reports of ASD symptoms did not differ between children who were diagnosed in schools and those diagnosed in medical clinics. The researchers inferred that schools may be identifying children with milder ASD symptoms that go undetected by clinicians. Or, schools are misdiagnosing students.

These differences in ASD diagnosis may be problematic. Studies have shown that students diagnosed with ASD can have lower expectations in the classroom compared to other students. Consequently, students with ASD may only perform up to these standards, even if they have milder ASD symptoms. If schools are misdiagnosing ASD, they could subject mislabeled students to the hampering effects of a stigmatized educational environment.

Autism spectrum disorder is exactly that, a spectrum. Similar to how a slight change in wavelength reflects a new, vibrant color, the needs of those with ASD bend with every small variation in symptoms. Comprehensive diagnostic measures that account for the perspectives of parents, teachers, and practitioners, can better address individual differences in ASD.

Overdiagnosis may be harmful, but underdiagnosis raises the risk of delayed intervention, and increased long-term developmental problems.

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