Adults newly diagnosed with autism today look very different on paper than those diagnosed in 2010, a study of 33 million people found
Adult autism diagnoses have risen sharply in many countries over the past 15 years. Researchers in the UK and Sweden went through the medical records of more than 33 million adults, 24.5 million in the UK and 9.1 million in Sweden, covering the years since 2010. Among them were 141,119 people diagnosed with autism in the UK and 100,817 in Sweden. The team compared what the medical histories of newly diagnosed adults looked like at the start of that period and at the end.
The medical profile of adults newly diagnosed with autism has changed a lot. In the UK, a history of epilepsy among newly diagnosed adults fell from 10% in 2010 to 4% in 2023, while a history of anxiety rose from 29% to just over 58%.
More broadly, the conditions people had before their autism diagnosis shifted away from epilepsy, psychosis and intellectual disability and toward ADHD, anxiety and depression. Adults diagnosed today are, on paper, a quite different group from those diagnosed in 2010.
New adult diagnoses were consistently more common in Sweden than in the UK, but the number of new cases in the UK rose sharply over the period.
The findings fit a wider change in how autism is understood. Over the past 15 years, awareness of autism in people without intellectual disability, and in women and adults who learned to mask their differences, has grown. People who struggled for years with anxiety or depression are now more likely to be assessed for autism as adults.
The study does not say whether the change is good or bad. It could mean that many autistic adults who were previously missed are finally being recognized. It could also mean that the boundaries of the diagnosis are shifting. The researchers say the results matter for services and research, because studies of autistic adults from 2010 may not describe the people being diagnosed today.
The second finding is about how the two countries compare. Sweden had higher diagnosis rates throughout, yet both countries showed the same shift in the medical histories of newly diagnosed adults. Getting the right diagnosis for symptoms that are easy to dismiss is a recurring theme in health research, as with women whose autoimmune symptoms were blamed on their mind.
For adults wondering whether autism might explain long-standing difficulties, the findings are a reminder that many people now receive the diagnosis after years of being treated for anxiety or depression, and that asking for an assessment is increasingly common.
There are limits to what this shows. The study relies on medical records, which reflect what doctors recorded rather than a full assessment of each person. It is observational and cannot explain why the profiles changed. Diagnostic practices, waiting lists and recording habits differ between the UK and Sweden and over time.
Source
“Changes in the profile of adults diagnosed as autistic since 2010: population-based studies in the UK and Sweden.” BMJ Mental Health, 2026.
DOI: 10.1136/bmjment-2026-302983
