Delayed Diagnosis and Missed Opportunities for Early Autism Identification in Brazil: An Exploratory Scoping Review

Background/Objectives: Timely identification of autism spectrum disorder (ASD) is essential for access to early intervention; however, diagnostic delay remains a persistent challenge. Methods: This scoping review synthesized evidence from eight studies (>24,000 participants), most conducted in the Southeast region, on diagnostic pathways, screening practices, and barriers to ASD identification in Brazil, following PRISMA-ScR guidelines. Results: Across studies, mean age at diagnosis frequently exceeded 48–60 months, while the interval between first caregiver concern and diagnosis ranged from 24 to 36 months, with tertiary-care samples reporting diagnostic ages approaching 79 months. Diagnosis was predominantly specialist-driven, with limited involvement of primary care providers (PCPs). Later identification was associated with reliance on the public health system in a multinational analysis that included Brazil, while geographic concentration of specialized services and socioeconomic inequalities were identified as reported barriers across the included studies. Race/ethnicity was rarely reported. Delays emerged from interacting multilevel barriers, including limited caregiver awareness, dismissal of parental concerns, inconsistent developmental surveillance, fragmented referral pathways, and shortages of specialists. Structural inequities, particularly geographic disparities and urban concentration of services, compounded these challenges. Conclusions: The evidence suggests delayed ASD diagnosis in Brazil reflects systemic gaps in care organization rather than isolated clinical factors. Strengthening PCP-based developmental surveillance and improving referral coordination are key strategies to reduce preventable delays and promote earlier access to intervention.