Autism Diagnostic Observation Schedule (ADOS) in Unequal and Low-Resource Systems of Care

Abstract

The Autism Diagnostic Observation Schedule (ADOS) and its second edition (ADOS-2) have acquired a de facto “gold standard” status for reliably diagnosing autism in the United States, even though the developers themselves emphasize that the instrument should be used as part of a holistic, clinically driven developmental assessment. This narrative review is informed by diagnostic accuracy studies and the global mental health relevance of ADOS/ADOS-2 to lowand middle-income countries (LMICs) using Türkiye and the United States as point of contrast. We consider the benefits of ADOS/ADOS-2 —its contribution to standardized observation, cross-site comparability, and detailed phenotyping in research and complex clinical cases—as well as its limitations, including extensive training requirements, time-intensive administration, high kit costs, proprietary licensing, and tightly regulated translation policies. These factors substantially limit the practicality of routine ADOS/ADOS-2 use in LMICs and other resource-constrained settings, where most autistic children live. In the United States, ADOS/ ADOS-2 based assessments have become deeply integrated into specialty services and, in some regions, even informally mandated by insurers or school systems, with consequences for wait times, access, and equity. In Türkiye, autism is primarily diagnosed through clinical assessment by child and adolescent psychiatrists without formal requirements for ADOS/ADOS-2, which expands clinical autonomy but results in less standardization and weaker cross-site consistency. We argue that treating the ADOS/ ADOS-2 as a universal diagnostic “gold standard” is unachievable given the global public health resource constraints in LMICs. Autism diagnosis, service eligibility, and research, especially in such a poor resource setting will require scalable, open-access, and cost-effective tools for both routine care and population-level studies.