Autism is a state in a state of slow flow. In 2021, a study found a 787% increase in the number of diagnoses between 1998 and 2018 in the United Kingdom.
Increases in diagnoses have been a feature of autism for nearly as long as it has been a recognized condition: 80 years agoAutism is thought to affect one in 2,500 children. It has gradually increased and now one in 36 children are believed to have autism spectrum disorder (ASD).
This exponential rise is due in part to greater awareness and deeper understanding of the condition, as well as more clinicians being able to make the diagnosis. This has led to what one expert called autism’s “widening assessment boundaries – boundaries that keep moving outward”.
Those boundaries include a wide range of people for whom autism would never be considered a possible diagnosis, especially women and girls. The resulting awareness has led to large numbers of adults seeking medical referrals to clarify differences they have been aware of since childhood.
But other factors behind the increase remains controversial, with those in the neurodiversity movement and experts unsure whether the increase is also due to overdiagnosis or whether more children have the condition.
The author of the 2021 study says the boundaries of diagnoses may expand further. Prof Ginny Russell, at the University of Exeter, said: “I think it’s going to continue until maybe everyone is categorized as neurodiverse.”
Russell said while there could be an argument that there was a marginally higher percentage of children with autistic traits who had low support needs than before, there was “no plausible” reason” to support an argument that autism cases have increased significantly.
“What has happened is that diagnoses have increased as a result of ever wider assessment boundaries – boundaries that continue to move outward,” she said. “Some go so far as to suggest that people diagnosed with autism today are united simply by not fitting into their social environment.
“This may soon include people like me, for example. I haven’t changed, but if I have some autistic features, I could soon be absorbed by autism – because it is changing itself.”
Russell is not alone in noting the huge increase in diagnoses. “When I started in this field in the 1980s, autism was considered quite rare,” said Prof Simon Baron-Cohen, the director of the Autism Research Center. “But there has been a massive shift in the last few decades, during which the increase in diagnoses has been exponential.”
The National Autistic Society describes autism as a “set of conditions containing a wide spectrum of disabilities”. And there was a 50% increase in the number of patients with an open referral for suspected autism in England in the last 12 months.
But there are those who say that even this increase is not accurate: others research suggests that the total autistic population in England and Wales is more than 1.2 million – almost double the figure of 700,000 quoted by the government for the whole of the UK. This would be the case if the rate of diagnosis matched that for under-19s across all ages, the study says.
Elizabeth O’Nions, the study’s lead researcher, said autism was still being recognized among adults, with more than 90% of all autistic people over 50 in England possibly undiagnosed.
But Dr Peter Carpenter, the chairman of the Neurodevelopmental Psychiatry Special Interest Group, questioned this, pointing out that adult diagnostic services do not necessarily have the expertise needed to review the adult population against modern criteria. “We probably don’t have a realistic idea of what a ‘typical autistic 50-year-old’ looks like,” he said.
There have also been changes when it comes to understanding autism among those with learning disabilities: in the 1980s, only a quarter of those with learning disabilities were thought to have autism. Now the NHS recognized that it can be as high as three quarters. “It’s an incredibly steep rise,” Baron-Cohen said.
Another increase in autism numbers is due to the removal of Asperger syndrome as a diagnosis. The label, created in 1994, was officially retired in 2013, with the condition falling under the umbrella term of autism.
Another important moment of change was the neurodiversity movement of the late 1990s, which drove major changes in identification, combating stigma and redefining autism as an identity rather than a disease. All this led to what Russell calls the “loop”.
“An increase in diagnoses leads back to increased awareness, which has an impact on how people identify themselves, which leads to a call for more assessment centres, which has led to a greater increase in diagnoses,” she said.
“As awareness and diagnoses increase, those with less severe symptoms are coming forward with their own stories of how autism affects them. The diagnostic criteria are expanded to take these accounts on board, which in turn leads back to another increase in diagnoses.”
In short, there is no clear answer about what autism is – or isn’t. Some say there never will be.
William Mandy, a professor of neurodevelopmental conditions at University College London, believes the nebulous nature of autism is a defining feature of the condition.
He said: “What are the characteristics we must have before we label someone as autistic?. It’s such an impossible question to answer that I think we should have a numerical cut-off – maybe we should just say 2% of the population is autistic.”
The one thing that matters even more than the profound questions surrounding autism diagnosis is the sad truth that autistic people too often do not lead happy lives. Compared to non-autistic people, they are about 70-0% more likely to have poor mental and physical health, experience educational underachievement, unemployment and underemploymentvictimization, social isolation and premature death.
The NHS is doing its best but there has been a 350% increase in children waiting for an autism assessment since the height of the Covid pandemic, with waiting times of more than two years.
Child and Adolescent Mental Health Services (Camhs) are at breaking point: 80% of children’s mental health referrals are autism-related in some areas of the UK. Some NHS commissioners have new reference criteria introduced trying to cut lists in a move parents say puts children at risk of harm, including suicide.
This has led some to ask whether the main goal of autism research should be refocused on understanding how to help autistic people lead happier lives.
Mandy said: “We are currently very focused on making a ‘yes’ or ‘no’ distinction in terms of diagnoses. But why not say, ‘Someone has these qualities. How can it affect their life and what can we do to help’?”
