Broader autism definition may lead to confusion and possible misdiagnosis

The definition of autism may have become so wide that it risks confusion and even misdiagnosis, according to a new editorial by UCL Professor Dame Uta Frith, whose pioneering research in the 1960s and 70s lay the foundations for how we understand autism.

Autism is currently diagnosed as Autism Spectrum Disorder (ASD) - a single condition that includes a huge range of people, from those needing round-the-clock care to those who live independently.

In Dame Uta's editorial, published in Psychological Medicine, she argues that this "spectrum" may now be too broad to be useful.

"Autism wasn't always defined this way – a sort of catch-all diagnosis for a huge variety of conditions," she said.

"When it was first identified in the 1940s, it referred to a small group of children with severe difficulties in social interaction, communication and behaviour. Over time, the definition has widened to include people with milder traits and no language or learning problems.

"Today, anyone of any age or intelligence level can be diagnosed with autism if they meet certain criteria."

The number of people diagnosed with autism has increased dramatically. In the 1960s, in the UK, about 4 in 10,000 children were diagnosed. Today, it's around 1 in 57 schoolchildren in the UK - a more than 40-fold increase.

In the paper, Dame Uta, Emeritus Professor of Cognitive Development (UCL Institute of Neurology) suggests several reasons for this rise:

• Greater awareness and less stigma
• Broader interpretation of diagnostic criteria
• More people identifying with autism online
• Self-diagnosis and social media influence
• A cultural shift toward explaining everyday life problems via medical labels

In a career spanning more than 50-years Dame Uta has researched the cognitive underpinnings of autism, longer than nearly anyone else.

With her colleagues she developed two landmark theories about how autistic minds might develop differently to neurotypical minds.

• Theory of Mind deficit (mentalising problems): The idea that autistic people may find it harder to infer other people's thoughts, beliefs and intentions.

• Weak Central Coherence: This theory proposed that autistic cognition tends to focus on details rather than the bigger picture. Autistic individuals may excel at noticing fine details but find it harder to integrate them into a broader, contextual understanding.

She, along with colleagues at UCL, was also among the first to explore the neural basis of these differences using newly available brain scanners in the 1990s.

Two very different groups?

In her new paper, a key argument made by Dame Uta is that not all autism diagnoses look the same. The latest research now shows a big difference between people diagnosed in childhood and those diagnosed later (as teenagers or adults).

• Early-diagnosed individuals often show clear signs from a young age and may have language or learning difficulties.
• Late-diagnosed individuals are more likely to have average or high intelligence and may also have conditions like anxiety, depression, or ADHD.

Some studies even suggest these groups may have different genetic patterns, raising the possibility that they are not the same condition at all.

Could this lead to misdiagnosis?

In the paper, Dame Uta, warns that expanding the definition of autism may lead to overdiagnosis, where people are given an autism label even when another condition might explain their difficulties.

"This matters because diagnoses shape treatment, identity, and support. A wrong diagnosis can lead to the wrong help - or no help at all," she said.

Dame Uta also points out that:

• There is no biological test for autism
• Diagnosis often depends on judgement and self-report
• Concepts like "masking" (hiding difficulties) can make the criteria even broader

The role of culture and identity

She said: "Autism is no longer just a medical term - it has become part of popular culture. Social media, films, and online communities have helped people share experiences, but they have also spread simplified or misleading ideas.

"At the same time, the idea of "neurodiversity" has encouraged people to see autism as a difference rather than a disorder. While this helps reduce stigma, it also creates tension: if autism is not a disorder, why use a medical diagnosis?"

What needs to change?

The paper calls for a rethink of how autism is defined and diagnosed. Instead of one broad "spectrum," it suggests:

• Splitting autism into clearer subgroups
• Focusing on individuals' specific needs
• Prioritising support for those with the greatest difficulties
• Improving diagnostic precision to avoid confusion and misdiagnosis

Dame Uta said: "The time has come to examine whether the autism spectrum has become too broad. Without greater precision, we risk misunderstanding people's needs and misdirecting care."

Professor Dame Uta Frith was awarded a Damehood in 2012 for her pioneering, foundational contributions to clinical science and the understanding of autism and dyslexia.