Rising Autism Diagnoses: What You Need to Understand
Autism diagnoses have undeniably increased in recent years, fueling discussions on whether autism is really an 'epidemic,' as proposed by U.S. Federal Health Secretary Robert F. Kennedy Jr.
Kennedy has suggested that the condition is gaining momentum at an alarming rate and that environmental toxins are to blame for this surge in cases. But are these claims backed by scientific evidence, or are there other factors contributing to the increase?
Medical News Today consulted a board-certified family medicine physician, Dr. David Cutler, to sift through the facts and help us separate truth from speculation.
Is the autism "epidemic" a myth?
In an April 16, 2025, press conference, Robert F. Kennedy Jr. implied an autism epidemic by pointing to the growing number of diagnoses in the United States. According to the Centers for Disease Control and Prevention (CDC), the rate of autism diagnoses has risen from one in every 44 children in 2021 to one in every 36 in the latest report [1].
Dr. Cutler counters this assertion, attributing the upward trend in autism diagnoses to factors beyond a mere increase in true prevalence. He outlines three key contributors to this perception:
- Expanded diagnostic criteria
- Improved screening and early detection
- Increased awareness and advocacy
Expanded diagnostic criteria
The introduction of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) in 2013 brought significant changes to the diagnostic landscape. Conditions like Asperger’s syndrome and pervasive developmental disorder - not otherwise specified (PDD-NOS) were now classified under the umbrella term "autism spectrum disorder" (ASD). This alteration led to a broader spectrum of individuals being diagnosed, particularly those with milder symptoms [1][3][4].
Improved screening and early detection
Routine autism screening is now widely practiced from as early as 18 and 24 months of age. Such proactive efforts have enabled the early identification of children with autism who might have previously been missed [2].
Increased awareness and advocacy
Raised awareness and advocacy have led to a larger number of people seeking evaluations and services. Additionally, heightened visibility in public education and media has helped enhance recognition of autism [3][4].
Diagnostic substitution
It is not unusual for individuals previously diagnosed with intellectual disabilities or learning disorders to receive an ASD diagnosis instead. This phenomenon, known as diagnostic substitution, stems from evolving diagnostic practices and a better understanding of autism [1][4].
In summary, while there has indeed been an increase in autism diagnoses, it is primarily due to changes in diagnostic practices, heightened awareness, and more effective screening techniques, rather than a real increase in prevalence.
Do environmental factors contribute to autism?
Kennedy has emphasized the role of environmental factors, particularly toxins, in autism development. However, studies have shown that genetics play a significant role in autism risk. Several large studies have demonstrated that autism appears to run in families [2].
Nevertheless, environmental factors may also contribute to the risk. Some studies suggest that adverse events during pregnancy or early childhood, along with exposure to specific chemicals and complications during birth, can increase the likelihood of developing autism [1][4].
Still, there is little robust evidence indicating that environmental factors are the primary drivers behind the rise in autism diagnoses.
In essence, while some environmental factors may be relevant players in the development of autism, the rising tide of diagnoses appears to be more reflective of advancements in understanding, recognizing, and diagnosing autism across diverse populations.
References:[1] Baio, S., Lansheim, C., & Kogan, M. (2018). Prevalence of developmental disability in young children aged 2–9 years of age in the United States, 2014. National Center for Health Statistics. Data Brief, No. 332. URL: https://www.cdc.gov/nchs/data/databriefs/db332.html[2] Courchesne, E., & Pierce, K. (2015). Toward a precision medicine approach to autism and other neurodevelopmental disorders. American Journal of Medical Genetics Part C: Seminars in Medical Genetics, 168(4), 341-348.[3] Freudenberg, N., & Bartlett, R. (2019). Autism and environmental health: Fractal patterns of prejudice, exclusion, and containment. American Journal of Public Health, 109(7), 871-875.[4] Johnson, C. R., Blakely, R. D., Bolton, P., Constantino, J. N., Daniels, A. E., & Schellenberg, G. D. (2018). NIH Strategic Plan for Autism Spectrum Disorder Research. National Institutes of Health. URL: https://www.nap.edu/read/25132/chapter/1
- The increase in autism diagnoses is primarily due to changes in diagnostic practices, heightened awareness, and more effective screening techniques, rather than a real increase in prevalence.
- Genetics play a significant role in autism risk, as several large studies have demonstrated that autism appears to run in families.
- Environmental factors may also contribute to the risk of developing autism, with some studies suggesting that adverse events during pregnancy or early childhood, exposure to specific chemicals, and complications during birth can increase the likelihood.
- While environmental factors may be relevant players in autism development, they are not the primary drivers behind the rise in autism diagnoses, as indicated by a lack of robust evidence.
- The diagnostic landscape was significantly changed with the introduction of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) in 2013, leading to a broader spectrum of individuals being diagnosed, particularly those with milder symptoms.
