All issues > Volume 0(0);

Review Article

Published online: October 2, 2025

DOI: https://doi.org/10.3345/cep.2025.00969

Bridging the gap: autism spectrum disorder in children in the United States and worldwide: a narrative review

Sandhya J. Kadam, MD¹, Malika Goel, MD²

¹Department of Pediatrics, Family HealthCare Network, Visalia, CA, USA

²Fellow Pediatric Gastroenterology, University of California, San Francisco, CA, USA

Corresponding author: Sandhya J. Kadam, MD. Department of Pediatrics, Family HealthCare Network, 4121 W Elowin CT, Visalia, CA, USA Email: hellosandhya7@gmail.com

Received April 26, 2025       Revised July 21, 2025       Accepted July 21, 2025

Copyright © 2025 by The Korean Pediatric Society

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by difficulty with communication and social interactions as well as restricted or repetitive behaviors. Over the last few decades, the prevalence of ASD has increased globally, with major differences in reporting, diagnosis, and interventions between developed and developing countries. The United States (U.S.) has seen a sharp rise in diagnosed ASD cases, with a current prevalence of approximately 1 in 31 children, due to improved awareness, early screening programs, and timely intervention. The U.S. healthcare system supports early intervention services through policies such as the Individuals with Disabilities Education Act and insurance mandates for ASD coverage. However, countries in Latin America, Africa, and Asia face challenges in ASD care, including limited access, stigma, underdiagnosis, and lack of resources. The World Health Organization Caregiver Skills Training, a global initiative, and the involvement of nongovernmental organizations are gradually bridging this gap. An interprofessional approach highlighting cross-cultural research, training providers, screening tools, referral options, policy implementation, and community-based care on a global scale will help reduce disparities in ASD care among countries. Making ASD care a global public health priority could help ensure developmental and mental healthcare equity. This study compares ASD care in the U.S. to that worldwide, highlighting the importance of global collaboration for early detection, service availability, and research.

Key words: Autism spectrum disorder, Applied behavior analysis, Communication social interaction, Occupational therapy, Child

Key message

The prevalence of autism is increasing worldwide. The United States has the highest numbers, likely due to the availability of better treatment options. However, global disparities exist, especially in low-resource settings in which stigma, underdiagnosis, and limited services hinder care. A coordinated international approach emphasizing early screening, inclusive policies, and culturally sensitive support systems can bridge this gap and improve the outcomes for children with autism and their families worldwide.

Introduction

Introduction

Autism spectrum disorder (ASD) is among the most prevalent neurodevelopmental disorders in children. While its management has advanced significantly in some parts of the world, especially the United States (U.S.), disparities persist globally.

Children with ASD in U.S.

Children with ASD in U.S.

According to the Centers for Disease Control and Prevention Autism and Developmental Disabilities Monitoring Network report, the prevalence of ASD in the U.S. is currently approximately 1 in 31 children compared to 1 in 150 in 2000 [1]. This increased prevalence is likely related to enhanced awareness, screening and diagnostic tools, and early intervention facilities. Pediatricians routinely screen children for ASD at 18 and 24 months using ASD screening questionnaires such as the Modified Checklist for Autism in Toddlers, Revised (M-CHAT-R) [1].

The M-CHAT-R and M-CHAT-R with Follow-up (M-CHAT-RF) consist of 20 questions each. In the M-CHAT-R, responses are recorded as yes or no, whereas in the M-CHAT-RF, they are marked as Pass or Fail. For children who receive a normal M-CHAT score of zero, the expected pattern of responses is as follows: questions 2, 5, and 12 should be answered "no," and all remaining questions should be answered "yes." Any deviation from this response pattern is considered abnormal, with each incorrect answer contributing 1 point to the total M-CHAT score. M-CHAT grading indicates patients at low, medium, or high risk [2].

A score of 0–2 on the M-CHAT-R indicates low risk, for which no further action is necessary. A score of 3–7 suggests moderate risk; in such cases, the M-CHAT-RF should be administered. Only the items marked as at risk on the initial M-CHAT-R are then reviewed during follow-up. If 2 or more of these items remain at risk after follow-up, the child should be referred immediately for further evaluation. Children who score 8–20 are considered at high risk and should be referred immediately for a comprehensive diagnostic assessment and early intervention services. Additionally, if there are concerns about possible signs of ASD from the pediatrician or parent, a referral should be made regardless of the child’s M-CHAT score [2].

Children are referred to specialists for speech, vision, hearing, and ASD evaluations. Children at medium risk are re-evaluated using the M-CHAT-RF, and further management is decided based on the re-evaluation scores. All patients with speech delays begin speech therapy, and based on the confirmation of ASD, start receiving specific ASD services. Insurance coverage mandates support therapies such as applied behavior analysis (ABA) and occupational and speech therapy. However, insurance benefits for ASD services vary significantly across states and are influenced by insurance plan coverages. The National Institutes of Health provides research funding, while organizations such as Autism Speaks advocate for advanced services and support networks. These systems help with the inclusion of, acceptance of, and early intervention for children with ASD [3].

Public school systems are mandated to support children with ASD under the Individuals with Disabilities Education Act (IDEA) [1]. According to the IDEA, children under 3 years of age at risk of developmental delays are eligible for early intervention services. Treatment of specific symptoms, such as speech therapy for language delays, does not require the receipt of a formal ASD diagnosis. Children with ASD and other disabilities are eligible for services through the local education system starting at 3 years of age by receiving an Individualized Education Program or 504 plan and starting services before formally starting school. Parents can also ask for an evaluation by contacting their local public school system, even if the child is not yet old enough for kindergarten or not enrolled in a public school through a program called "Child Find." [4]

Under the IDEA, children with ASD receive a range of free services in public schools, including speech and occupational therapies to support fine motor skills and sensory processing. They also receive physical therapy to address motor development and movement difficulties and behavioral interventions to address challenging behaviors and promote positive behaviors. The program also provides social skills training and assistive technology, such as tablets, to enhance the child's learning and communication. ABA develops specific skills in a systematic manner to improve the overall quality of life of children with ASD. The IDEA mandates that children with disabilities, including those with ASD, be educated alongside their nondisabled peers whenever possible to foster inclusion and social interactions [4].

Children with ASD worldwide

Children with ASD worldwide

Asian, African, and Latin American countries face major obstacles to ASD care. Their exact prevalence data are not available because of underdiagnosis related to stigma, cultural factors, limited screening tools, and a lack of management services. According to a study in 2022 by Zeidan et al. [5], the global ASD median prevalence within and across regions is 100/10,000 (range, 1.09/10,000–436.0/ 10,000). In India, studies report a wide ASD prevalence range (0.09%–1%) depending on the population and diagnostic criteria used [5].

In Sub-Saharan Africa, ASD remains highly stigmatized and is often misunderstood as a spiritual or behavioral issue rather than a medical condition. Limited healthcare infrastructure, scarce resources, and lacking public policy create further barriers to care [6]. Similarly, in parts of Southeast Asia and the Middle East, the diagnosis often occurs late; moreover, only few educational or therapeutic services are available. Language, cultural beliefs, and socioeconomic constraints also affect its perception and management. In low-resource areas, social stigma, shame, and cultural norms dominate, leading families to conceal their children’s conditions and seek alternatives [6].

Despite the presence of disparities between developing and developed countries, the global prevalence of ASD is increasing, likely due to the efforts of individual countries, the World Health Organization (WHO), and the involvement of nongovernmental organizations. In India, along with the M-CHAT, the Trivandrum Autism Behavioral Checklist and Social Communication Questionnaire (SCQ) are used to screen for and evaluate ASD [7].

In 2023, Chakrabarti [8] described various factors, such as population size, diet, environmental, genetic, social, and economic, and the inclusion of children with ASD in mainstream schools in India, as components of effective ASD management as well as the need to create a national ASD program.

In South Korea, along with the M-CHAT and SCQ, the Social Responsiveness Scale and Behavior Development Screening for Toddlers are also used. Developmental screenings are performed 8 times in children aged 2 weeks to 6 years. The Korean Developmental Screening Test for Infants and Children includes 6 domains, and children older than 1 year of age are screened for additional items specific to ASD [9]. South Korea has a national program supporting patients with ASD. Children with ASD, speech delays, or intellectual disabilities can be registered with the Korea National Disability Registration System to obtain social welfare benefits [10]. South Korea is making progress in helping children with ASD. However, some target areas require more investment and development, as Kim et al. [11] studied in 2019 by comparing ASD services in Massachusetts, U.S., and Seoul, Korea.

According to the National Autistic Society, approximately 1% of the population in the United Kingdom (U.K.) has ASD. The U.K.'s National Strategy for People 2021–2026 highlights key roles such as ASD acceptance and understanding, improved educational opportunities, healthcare equality, and helping young adults become more independent and transition smoothly to adulthood. This policy covers children, young people, and adults with ASD [12].

Based on data from the Department of Social Services, National Disability Insurance Agency, increasing Australians have ASD, with higher risk of premature deaths, unemployment, and academic difficulties, Australia has developed a national ASD strategy that includes 22 commitments highlighting services provided to, diagnostic strategies for, and health and social economic help for patients with ASD [13].

In 2023, a study conducted in New Zealand described the current policy and plans to support patients with ASD, which highlighted its national ASD strategy to enhance educational, social, economic, and inclusion opportunities and provide future research directions [14].

The prevalence of ASD has been steadily increasing over the last 3 decades in European countries, with estimates of 1%–2% among schoolchildren. In 2023, Mendez et al. [15] surveyed 3 European countries to examine the challenges to receiving ASD care. The study found some barriers, such as long waiting times to obtain a diagnosis, limited access to interventions, a lack of sufficient support for families, and unavailability of adequate information about ASD. These findings highlight the need to strengthen European policy to improve the quality of life of children with ASD and their families.

In 2023, Fong et al. [16] studied the needs of native and newcomer families of patients with ASD in Canada. In that study, native families preferred to receive services in rural and remote areas while preserving their cultural norms. Newcomer families prioritized quality services, including therapy and peer support. Both groups reported longer wait times similar to those of the general population. The findings emphasize the need for service structure and function to accommodate the needs of patients with ASD in underserved communities.

Efforts to minimize disparities

Efforts to minimize disparities

Despite these challenges, several global initiatives have been developed. The WHO Caregiver Skills Training program empowers parents of children with developmental disorders, including ASD, via community-based training sessions in more than 30 countries. Nongovernmental organizations and local advocacy groups are working to improve awareness and provide support, while academic partnerships are helping to develop culturally appropriate screening tools [17].

After receiving feedback from widespread field testing in various regions and discussions with international experts, family advocates, caregivers, and service providers, the WHO has created 5 different packages of the Caregiver Skills Training program for parents of children with disabilities, including ASD, to increase their parenting skills and confidence. The program is delivered by nurses, community-based workers, or caregivers and includes health education and social services for children and their families. The 5 Caregiver Skills Training program documents include introduction, adaptation, facilitator, participant, and home sections [18]. The program includes 9 group sessions and 3 home visits to teach caregivers how to include a child's daily activities to promote social interaction, communication, and learning. The sessions target participation, development, engagement, daily living skills, the management of challenging behaviors in children with ASD, and the development of coping strategies for caregivers [18].

Autism Europe, an international organization, is improving the quality of life of people with ASD and their families in 40 European countries via 90 ASD organizations. Autism Europe is increasing public awareness and advocating for the rights of patients with ASD [19].

ASD care and services differ significantly between developing and developed countries within specific regions. However, each country is making progress at both regional and national levels. For example, developed nations such as the U.K. have introduced initiatives such as the National Autism Strategy 2021–2026 [12]. There are several national and international resources for ASD empowerment, including ANCA and Autism Society in Canada, Irish Society for Autism in Ireland, Autism All Stars UK, and The National Autistic Society in UK, Autism Association of Western Australia, and Autism Aspergers Advocacy in Australia. There are multicultural ASD organizations, such as Autismo Diario and online ASD communities, such as MyAutismTeam and WrongPlanet.net, that help patients with ASD [20]. (Tables 1, 2)

Future directions

Future directions

ASD care must be prioritized within national health and education strategies; moreover, there is a need for extensive efforts to close this gap. Training healthcare professionals through continuous medical education programs and the integration of M-CHAT screening at the 18- and 24-month wellness visits for every child can aid the early diagnosis. Moreover, future research to understand the different presentations of ASD across countries affected by cultural factors could aid the development of tailored interventions. Thus, a global response must extend beyond diagnostics and include support and social inclusion for families. Equity in ASD care requires policy, community, and healthcare system alignments. Learning from the U.S. experience of adapting successful models to the local context and international collaboration can facilitate the sharing of ASD knowledge, resources, and management options among healthcare professionals. ASD has no geographical limitations, but its available resources are limited; therefore, addressing this gap is a moral responsibility [1-20].

The early diagnosis of ASD can help children receive early intervention services to facilitate patient acquisition of adaptive skills, improve long-term outcomes, and improve the overall quality of life of patients and families. In 2023, Okoye et al. [21] reviewed the benefits of the early diagnosis of ASD as well as the possible risks, including overdiagnosis or misdiagnosis. An early ASD diagnosis can cause social stigma that affects the child's interaction with their environment. Children and caregivers face the complicated process of an ASD evaluation performed by different specialists to arrive at a challenging diagnosis. That review emphasized the importance of using a logical approach, using correct tools, and including artificial intelligence to arrive at an accurate, confirmatory, and timely diagnosis of ASD.

Conflicts of interest

Conflicts of interest

No potential conflict of interest relevant to this article was reported.

Notes

Funding

This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Notes

Author contribution

Conceptualization: SJK, MG; Data curation: SJK, MG; Formal analysis: SJK, MG; Project administration: SJK, MG; Visualization: SJK, MG; Writing - original draft: SJK, MG; Writing - review & editing: SJK, MG

References

1. Shaw KA, Williams S, Patrick ME, Valencia-Prado M, Durkin MS, Howerton EM, et al. Prevalence and early identification of autism spectrum disorder among children aged 4 and 8 years — autism and developmental disabilities monitoring network, 16 sites, United States, 2022. MMWR Surveill Summ 2025;74:1–22.

2. Robins DL, Casagrande K, Barton M, Chen CM, Dumont-Mathieu T, Fein D. Validation of the modified checklist for Autism in toddlers, revised with follow-up (M-CHAT-R/F). Pediatrics 2014;133:37–45.
[Article] [PubMed] [PMC]

3. Hodges H, Fealko C, Soares N. Autism spectrum disorder: definition, epidemiology, causes, and clinical evaluation. Transl Pediatr 2020;9(Suppl 1):S55–65.
[Article] [PubMed] [PMC]

4. Centers for Disease Control and Prevention (CDC). Accessing services for autism spectrum disorder [Internet]. Atlanta (GA), Centers for Disease Control and Prevention. 2025;[cited 2025 Mar 3]. Available from: https://www.cdc.gov/autism/treatment/accessing-services.html.

5. Zeidan J, Fombonne E, Scorah J, Ibrahim A, Durkin MS, Saxena S, et al. Global prevalence of autism: a systematic review update. Autism Res 2022;15:778–90.
[Article] [PubMed] [PMC]

6. Talantseva OI, Romanova RS, Shurdova EM, Dolgorukova TA, Sologub PS, Titova OS, et al. The global prevalence of autism spectrum disorder: a three-level meta-analysis. Front Psychiatry 2023;14:1071181
[Article] [PubMed] [PMC]

7. Uke P, Gaikwad S, Vagha K, Wandile S. Unraveling the spectrum: a comprehensive review of autism spectrum disorder in India. Cureus 2024;16:e62753.
[Article] [PubMed] [PMC]

8. Chakrabarti B. Autism in India: time for a national programme. Indian J Med Res 2023;157:227–9.
[Article] [PubMed] [PMC]

9. Kim JI, Yoo HJ. Diagnosis and assessment of autism spectrum disorder in South Korea. J Korean Acad Child Adolesc Psychiatry 2024;35:15–21.
[Article] [PubMed] [PMC]

10. Kim M, Jung W, Kim SY, Park JH, Shin DW. The Korea National Disability Registration System. Epidemiol Health 2023;45:e2023053.
[Article] [PubMed] [PMC]

11. Kim JW, Kim HW, Moon DS, Lim YS, McDougle CJ, Howe YJ. Comparison of services for autism spectrum disorder in Massachusetts with those in Seoul. J Korean Med Sci 2019;34:e288.
[Article] [PubMed] [PMC]

12. GOV.UK. The national strategy for autistic children, young people and adults: 2021 to 2026 [Internet]. GOV.UK 2021 to 2026 [Internet]. Available from: https://assets.publishing.service.gov.uk/media/60f72556e90e0764c6eb39f5/thenational-strategy-for-autistic-children-young-people-andadults-2021-to-2026.pdf.

13. Young E, Campanella N. Australia now has a national autism strategy. Here's what's in it and why it's needed [Internet]. Sydney (Australia), Australian Broadcasting Corporation. 2025;[cited 2025 Mar 8]. Available from: https://www.abc.net.au/news/2025-01-13/national-autism-strategy-released-employment-inclusion-health/104792744.

14. van der Meer L, Moriah C, Patrick L, Waddington W. How do we get autism support right in Aotearoa New Zealand? Final Report. St Lucia, Autism CRC. 2024;[cited 2025 Mar 26]. Available from: https://www.autismcrc.com.au/news/latest-news/how-do-we-get-autism-support-right-inaotearoa-new-zealand.

15. Mendez MA, Oakley B, Canitano R, San José-Cáceres A, Tinelli M, Knapp M, et al. Autism care pathway in Europe. Eur Psychiatry 2023;66:e81.
[Article] [PubMed] [PMC]

16. Fong VC, McLaughlin J, Schneider M, Bruno G. Comparing the autism service needs and priorities of Indigenous and newcomer families in Canada: qualitative insights. Res Autism Spectr Disord 2024;111:102314
[Article]

17. World Health Organization. WHO caregiver skills training for families of children with developmental delays or disabilities. Training for caregivers of children with developmental disabilities, including autism [Internet]. Geneva (Switzerland), World Health Organization. 2020;[cited 2025 Mar 21]. Available from: https://www.who.int/teams/mental-health-and-substance-use/treatment-care/whocaregivers-skills-training-for-families-of-children-withdevelopmental-delays-and-disorders.

18. World Health Organization. Caregiver skills training for families of children with developmental delays or disabilities [Internet]. Geneva (Switzerland), World Health Organization. 2022;[cited 2025 Apr 1]. Available from: https://www.who.int/teams/mental-health-and-substance-use/treatment-care/who-caregivers-skills-training-for-families-of-children-with-developmental-delays-and-disorders.

19. Autism Europe. Who we are [Internet]. Brussels (Belgium): Autism Europe; [cited 2025 Mar 18]. https://www.autismeurope.org/who-we-are/.

20. National and International Resources. Autism empowerment [Internet]. Vancouver (WA), National and International Resources. 2025;[cited 2025 Apr 6]. Available from: https://www.autismempowerment.org/resource-center/nationaland-international-resources/.

21. Okoye C, Obialo-Ibeawuchi CM, Obajeun OA, Sarwar S, Tawfik C, Waleed MS, et al. Early diagnosis of autism spectrum disorder: a review and analysis of the risks and benefits. Cureus 2023;15:e43226.
[Article] [PubMed] [PMC]