Twentyfold jump in autism diagnoses in England over two decades

Researchers say 787% rise from 1998 to 2018 likely due to better understanding of autism

The number of people diagnosed with autism in England has jumped more than twentyfold in two decades, with a greater rise among females and adults, new research has found.

University of Exeter researchers say the 787 per cent rise from 1998 to 2018, identified using the GP records of more than nine million patients, is likely due to increasing recognition and understanding of autism.

There were just over 3,000 people with an autism diagnosis in England in 1998, and this had jumped to more than 65,600 20 years later. Adults went from accounting for 8.6 per cent of the recorded autistic population in 1998 to 16.2 per cent in 2018. This could be attributed, in part, to a UK policy introduced in 2009 that saw significant investment in adult assessment services.

Lead author and lecturer in diagnosis studies Ginny Russell said the results do not point to more people developing neurodevelopmental disorders “per se”. Rather, the over-representation of adults and females suggests the rise is due to increased identification.



The definition of autism has changed over time, Dr Russell added, and 20 years ago there were misconceptions that autism was a male disorder. In 1998, 81.7 per cent of people diagnosed with autism in England were male, and this had reduced to 77.5 per cent by 2018.

A spokeswoman for the Health Service Executive (HSE) said it does not routinely gather information on autism diagnoses and there is no specific autism register in Ireland.

Irish clinical psychologist Davida Hartman, who is a director at the Children’s Clinic and the Adult Autism Practice, said the increasing number of women being diagnosed is reflected at her adult practice, where 70 per cent of clients are female.

Ms Hartman believes the number being diagnosed in this State is an undercount of the autistic population. While autistic people work in a range of professions, many choose not to disclose their diagnosis due to the “real fear of stigma”.


A cohort of people have learned to “mask their differences”, she said, so assessors should examine the internal experiences of a client over their observable behaviours, which is considered “outdated”.

Diagnosis is a “really positive” experience for many, she said, adding that autism must be seen as a “different neurotype and [a] valuable way to be in this world”.

Adam Harris, director of As I Am, said Ireland’s most reliable autism diagnosis data is in the education sector, with the National Council for Special Education finding in 2016 that one in 65 schoolchildren (or 1.5 per cent) in the State had a diagnosis. It is “very concerning”, he said, that some cohorts of autistic children continue to be underdiagnosed, such as Travellers and girls. “There are a number of girls who can mask their diagnosis by copying other girls... While we are saying one in 65, there is every chance that that doesn’t tell the full story,” he said.

Statistics on the adult autism population are “vitally important”, said Mr Harris, because currently there is a population that is “invisible”. There are barriers still to both children and adults obtaining a diagnosis in this State, he said. There is no public pathway for adults to be diagnosed, and it is “utterly unacceptable” that a group that has already been marginalised must pay close to €1,000 to be assessed, Mr Harris added.

“There are many people who never received a diagnosis and never received supports,” he said.

Ellen O'Riordan

Ellen O'Riordan

Ellen O'Riordan is High Court Reporter with The Irish Times