The story so far:
Last month, United States Health Secretary Robert F. Kennedy Jr. announced a massive testing and research effort to identify the “environmental toxins” that he said were behind the growing “epidemic” of autism in the U.S. He said the Department of Health and Human Services would launch a series of new studies focusing on environmental substances — as, he claimed, research into genetic factors had been a “dead end”. Calling autism a “preventable disease,” he said there would be some answers by September this year.
Some of Mr. Kennedy’s remarks came following the release of a new report from the Centers for Disease Control and Prevention showing that rates of autism had increased from 1 in 36 children in 2020 to 1 in 31 in 2022. He dismissed the idea that the increases could be due to better identification of cases and changed diagnostic criteria, even though the CDC report itself attributed some of the increase to more screening for the condition.
Though Mr. Kennedy did not, at this time, link vaccines with autism, he is a known vaccine skeptic and has previously done so, even though that theory has been thoroughly refuted by years of scientific research.
What is autism?
Autism Spectrum Disorders (ASD), according to the World Health Organization (WHO), are a diverse group of conditions. They are characterised by some degree of difficulty with social interaction and communication. Other characteristics are atypical patterns of activities and behaviours, such as difficulty with transition from one activity to another, a focus on details, and unusual reactions to sensations. Characteristics of autism may be detected in early childhood, but autism is often not diagnosed until much later.
People with autism often have co-occurring conditions, the WHO states, including epilepsy, depression, anxiety, and attention deficit hyperactivity disorder, as well as challenging behaviours such as difficulty sleeping and self-injury.
The level of intellectual functioning among autistic people varies widely, extending from profound impairment to superior levels. The abilities and needs of autistic people vary and can evolve over time. While some people with autism can live independently, others have severe disabilities and require life-long care and support, it says.
What does the existing research say?
Existing research points to multiple factors, possibly both genetic and environmental factors. Research has also shown that the MMR vaccine that was linked to autism in a now widely debunked study does not cause autism, nor do other childhood vaccines increase the risk of autism.
“Autism is caused by a complex interplay of genetic, epigenetic, and environmental factors. A lot of research into the genetics side of it has been carried out — a lot of genes that are involved have been identified, but the list is not complete as yet; it continues to expand. More research into this is needed. Environmental factors that have been studied include exposure to air pollution, heavy metals, pesticides, screentime, as well as other factors such as the age and lifestyle of the parents at conception. Research into these factors is also ongoing,” says Sheffali Gulati, child neurologist, department of pediatrics, AIIMS New Delhi.
Is it preventable?
Prevention strategies may be complex, says Prof Gulati, due to the interplay of multiple factors, many of which remain unknown as yet; autism is not caused by one specific gene or one specific environmental factor. “In general, in healthcare, prevention consists of primary, secondary, and tertiary prevention. Here, if primary prevention may not be fully possible as of yet, as more research is needed to understand what is causing autism, it is important to focus on secondary and tertiary prevention, which consists of early diagnosis and picking up of cases as well as interventions to help,” she said.
“We’ve come a long way in understanding autism, and what we know from decades of research is that genetics play a major role, with heritability estimates as high as 91% in some studies (Tick et al., JAMA, 2016). While certain environmental exposures may influence development in utero, such as advanced parental age or prenatal exposure to air pollutants, there is no single environmental toxin scientifically proven to cause autism (Sandin et al., JAMA, 2014; Becerra et al., EHP, 2013). In fact, autism is not a disease in the classical form. It is a developmental difference shaped by a complex interplay of biology and environment. While some individual risk factors have been identified, none offer a path to broad prevention. Framing autism in this way is scientifically inaccurate and socially irresponsible. This kind of language risks placing blame on parents and caregivers, particularly mothers, for outcomes far beyond their control. It reinforces stigma and creates shame where there should be support,” says (via email) Tyler Evans, Adjunct Associate Professor, University of Southern California Keck School of Medicine, Department of Population and Public Health Sciences.
Ennapadam S. Krishnamoorthy, neuropsychiatrist and founder, Buddhi Clinic, Chennai, said that in order to know how to intervene, it was important to know if there were preventable risk factors and what they were, but while focusing on this, care must be taken to not shift the blame on to parents or to stigmatise individuals with ASD.
“So far,” said Gita Sankaran, founder, WeCAN, a resource centre for autism in Chennai, “since we do not fully know what we are trying to prevent and we do not even know if it is preventable, to call ASD preventable and to term people or parents as responsible or responsible is inappropriate.”
Is autism on the rise?
“The prevalence of ASD is growing,” said Dr. Krishnamoorthy, “and this is attributed to several factors, including recognition of the condition, as well as the criteria becoming more inclusive — the focus in the early years was on the more severe cases, but today, many of the less severe cases also fall under the autism framework.” Also, he said, apart from genetic propagation, there are a number of environmental factors today that could also be contributing to the rise, triggers that could be making ASD manifest. Socio-cultural ethos could also perhaps have a role to play in this, he said.
Overall, says Dr. Sankaran, there has been an increase in the number of diagnoses of individuals on the mild end of the spectrum, primarily because of increased awareness and access to information about ASD. As the population increases, however, there has been a proportionate increase in the total number of cases.
What is the need of the hour in ASD care and support?
At this point, says Dr. Krishnamoorthy, we are far from diagnosis every case early and intervening early, globally and so, this should still be the priority. As Dr. Evans says: “black, brown, immigrant, and low-income families already face huge barriers to diagnosis and service, often receiving diagnoses later and having less access to therapies and support.”
More psycho-education for families across the board, and a more realistic approach to interventions based on the needs of each child, are also vital, said Dr. Sankaran.
This apart, Dr. Krishnamoorthy raised the importance of combating misinformation, particularly related to autism being caused by vaccines, which, he said, had led to a drop in vaccination rates and could precipitate epidemics. “But crucially, more focus has to be given to maternal health during pregnancy. A lot of our current efforts in this direction are to do with communicable diseases, but non-communicable diseases, especially mental health, is not talked about enough. What can mothers and families do to ensure optimal environments for the growing foetus and for infants and toddlers — there has to be more awareness and more attention given to this area.”
Published – May 22, 2025 06:13 pm IST