Jul 2026· International Health Sciences Review· 0 citations
TL;DR
A narrative review critically analyzes early signs of ASD in childhood and the clinical, developmental, family, educational, and health-system consequences of delayed diagnosis and concludes that earlier recognition should not depend exclusively on a definitive label.
Abstract
Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental condition whose defining features often emerge before school age, although formal diagnosis may still occur after several missed opportunities for recognition. This narrative review critically analyzes early signs of ASD in childhood and the clinical, developmental, family, educational, and health-system consequences of delayed diagnosis. A selective, interpretive synthesis of guidelines, surveillance reports, systematic reviews, validation studies, and clinically relevant observational evidence was conducted, prioritizing publications from the last 15 years while retaining foundational diagnostic and screening sources. Early manifestations include reduced social reciprocity, atypical eye contact, limited response to name, delayed or unusual communication, restricted and repetitive behaviors, sensory differences, motor atypicalities, and developmental regression in some children. Evidence indicates that structured developmental surveillance, autism-specific screening, culturally adapted instruments, and rapid referral pathways can shorten the diagnostic pathway, but inequalities persist by sex, race, socioeconomic position, language, geography, and availability of specialized services. Delayed diagnosis may postpone early intervention, intensify family stress, increase school difficulties, contribute to mislabeling or diagnostic overshadowing, and widen disparities in access to care. The review concludes that earlier recognition should not depend exclusively on a definitive label; rather, children with developmental concerns should receive timely, individualized, family-centered support while diagnostic clarification proceeds.
It is argued that future early ASD detection systems should be developed as clinician-supervised decision-support tools rather than autonomous diagnostic instruments.
Wenhao Luo, Z. Yin, Jianbiao Dai· Diagnostics· 0 citations
The reported prevalence of autism spectrum disorder (ASD) has risen dramatically over the past two decades. Although increased awareness, broader diagnostic criteria, and improved access to assessment have corrected historical under-identification, this diagnostic expansion also raises a significant methodological concern: the risk of diagnostic dilution. Increasingly, surveillance systems and clinical cohorts may include individuals whose phenotypic profiles, developmental histories, and functional impairments do not fully align with a developmentally anchored neurodevelopmental presentation of ASD. This challenge is particularly acute in adolescent and adult assessments, where developmental history may be incomplete and standardized instruments or self-report measures may show limited specificity when applied to clinically complex psychiatric populations. Conflating developmentally anchored ASD with partially overlapping clinical phenotypes may reduce the signal-to-noise ratio in genetic, biomarker, neuroimaging, and therapeutic research, contributing to findings that are difficult to replicate or interpret. To preserve diagnostic validity, this Perspective argues that best-estimate clinical diagnosis must be grounded in rigorous developmental anchoring, collateral information, and judicious clinical judgment. It further proposes a set of core stratification domains for systematic phenotypic stratification, including age at first concern and diagnosis, biological sex and sex-related ascertainment factors, language and cognitive trajectories, adaptive functioning, intellectual disability, psychiatric comorbidities, ascertainment source, diagnostic instruments used, collateral developmental documentation, and support needs and functional impairment across contexts and over time. Stratification should not be understood as a restriction on clinical access, but as a scientific requirement for meaningful prevalence estimates and biologically informative autism research.
Gabriela N. F. Guimarães· Frontiers in Psychiatry· 0 citations
ABSTRACT Early autism identification in children aged 0–5 years is often discussed in terms of screening accuracy, yet consequential delay frequently occurs across the pathway from first concern to referral, diagnostic assessment, and support. This critical narrative review examines early autism identification as a pathway problem rather than as a single testing event. It synthesizes evidence on developmental surveillance, autism‐specific screening, parental and clinician concern, referral conversion, diagnostic waiting, service capacity, inequity, family burden, and pre‐diagnostic support. Screening tools can identify an elevated likelihood of autism and may accelerate diagnosis for some screen‐positive children, but they cannot confirm diagnosis or safely exclude autism when concern persists, and they do not compensate for failures in follow‐up, referral, assessment capacity, or support initiation. Recent evidence supports a cautious interpretation of universal autism screening because diagnostic stability, screening accuracy, and intervention benefit in screen‐detected children remain uncertain. Comparative evidence on the Modified Checklist for Autism in Toddlers, Revised with Follow‐Up suggests context‐dependent performance, including variable sensitivity, low or inconsistent positive predictive value, and age‐dependent accuracy. Multicultural surveillance and implementation studies indicate that adding tools without aligning workflow, language support, follow‐up systems, and service capacity may not improve pathway performance. The review argues that early autism identification should be evaluated through linked quality measures: response to concern, repeated surveillance following negative or ambiguous screening, referral completion, time to diagnostic assessment, support initiation before diagnostic closure, and equity of access. The clinical priority is not a perfect screening instrument in isolation, but faster, more coherent, and more equitable local pathways that translate concern into timely action.
R. Kurmashev, Mavile Karaieva· Pediatric Investigation· 0 citations
Highlights What are the main findings? • Delayed autism diagnosis in Brazil reflects multilevel barriers spanning families, providers, referral pathways, and health system organization.• Primary care played a limited role in early identification, while specialist-centered pathways and regional inequalities contributed to prolonged diagnostic trajectories. What are the implications of the main findings? • Earlier diagnosis may be improved by strengthening developmental surveillance, referral coordination, and primary health care capacity.• Future Brazilian research should prioritize standardized reporting, implementation studies, and broader geographic and equity-focused representation. Abstract 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.
Bianca Teeny Sallum, Monaliza Ehlke Ozorio Haddad, Maria Gabriela Custódio de Figueiredo et al.· Children· 0 citations
INTRODUCTION
Autism Spectrum Disorder (ASD) is a lifelong condition; however, literature regarding its manifestation in old age remains scarce.
OBJECTIVE
To synthesize descriptive studies on the clinical characteristics of ASD in the elderly, aiming to improve diagnosis and quality of life.
METHODOLOGY
This is a scoping review based on the Joanna Briggs Institute guidelines and reported according to PRISMA-ScR. Searches were conducted in MEDLINE/PUBMED and SCIELO databases, covering the period from 2011 to 2026, focusing on descriptive studies with participants aged over 50 years. Ultimately, 18 articles were selected and analyzed.
RESULTS
The evolution of autism symptoms proved to be complex and non-linear; while some behaviors and psychiatric symptoms tend to decline with age, social difficulties may persist or worsen. From a cognitive perspective, data suggest an aging pattern parallel to neurotypicals, although there are reports of specific deficits in working memory and attention. An alarming burden of psychiatric comorbidities was identified, highlighting depression and high rates of suicidality, as well as significant clinical comorbidities.
CONCLUSION
Older adults with ASD constitute a vulnerable population. There is an urgent need for prospective longitudinal studies to adequately map the aging trajectories of this population.
J. P. S. Gontijo, Marcelo H S S Martins, L. M. Alves· Trends in Psychiatry and Psy...· 0 citations
Highlights What are the main findings? A diagnosis of autism spectrum disorder (ASD) carries elevated risk(s) for multiple comorbidities across behavioural, psychiatric, and somatic domains. Data on the frequency of various comorbidities are presented alongside their profiles according to sex and age. What is the implication of the main findings? Such data forms the starting point for investigations into screening programmes for the early detection and intervention for various comorbidities which can impact quality of life. Abstract Background/Objectives: Autism spectrum disorder (ASD) is currently singularly described as a behaviourally defined neurodevelopmental diagnosis with symptoms affecting social communication and social understanding alongside the presence of restricted patterns of behaviour. Wide, and often very personal, variations in symptom intensities and differing developmental trajectories, reflective of large heterogeneity, are an important feature of the label. ASD carries enhanced risks for multiple over-represented, sometimes overlapping, comorbidities spanning behavioural, psychiatric and somatic domains. Said comorbidities often have numerous and far-reaching effects on quality of life by way of their impacts and, in extreme cases, their potential effects on life expectancy. It is of paramount importance that data on the risks of such comorbidities are available and, where possible, screening, preventive and/or treatment options implemented. Methods: In this narrative review, the authors searched databases (PubMed/Medline, ScienceDirect, Google Scholar) for papers published between 1 January 2015 and 16 February 2026 that were pertinent to comorbidity and autism. Results: We present data on the frequency of various somatic (gastrointestinal, immunological, metabolic, neurological, motor-sensory disorders), psychiatric (anxiety, mood, schizophrenia spectrum, personality, substance abuse, trauma, feeding and eating, sleeping, self-harm, neurocognitive disorders) and neurodevelopmental comorbidities (intellectual, attentional, speech and language, motor disorders) that can present alongside a diagnosis of ASD. We provide accompanying data on the magnitude of potential risk and, where available, information on comorbidity risks according to sex and age. Conclusions: This review paper deals with an extremely broad field. Limitations of the narrative review strategy are discussed alongside how the variable risk of comorbidity mimics the heterogeneity present in autism, thus inviting further investigations.
E. Dando, Juergen Hahn, D. Geier et al.· Healthcare· 0 citations