Most of the world’s children live in low- and middle-income countries. Yet few epidemiological studies of autism prevalence have been conducted in these countries, and little is known about how the symptoms of autism vary from culture to culture.
The limited data available suggest that outside North America and Europe, many cases of autism go unrecognized. A major barrier to diagnosis is the cost of assessments.
“There are glaring disparities globally, and even within the U.S., in terms of where the research on autism is being done, who is included in studies of autism and the diagnostic and therapeutic services available,” says Maureen Durkin, professor of population health sciences and pediatrics at the University of Wisconsin School of Medicine and Public Health.
Western Psychological Services, a publishing company based in Los Angeles, owns many of the common autism screening and diagnostic instruments. These include the Social Responsiveness Scale (SRS), a widely used screening questionnaire that Constantino developed, as well as the Autism Diagnostic Observation Schedule (ADOS) and the Autism Diagnostic Interview-Revised (ADI-R), often referred to as the gold-standard tests for diagnosis of the disorder.
Each time one of these tests is administered, the publisher charges a fee, and passes a portion of the royalties on to the test’s developers.
“I don’t think there’s any other condition in medicine in which you have to pay a royalty to a publishing company in order to make the diagnosis,” says David Skuse, professor of behavioral and brain sciences at University College London. Skuse has helped develop two freely available tools, the Social and Communication Disorders Checklist (SCDC) and the developmental, dimensional and diagnostic interview (3di).
In many countries, paying royalties of even a few dollars represents a substantial hardship. Durkin and others say these costs not only limit access to diagnosis for individuals, but also forestall epidemiological studies, which require surveying thousands of individuals.