Newly diagnosed adults with autism carry more anxiety, ADHD

Clinical takeaway: Watch for co-occurring depression and sleep problems in adults who have just received an autism diagnosis. 

Autism diagnoses in adults have climbed for years, and the reason is disputed. Better awareness, less stigma, and sharper recognition in women could be identifying people who were previously overlooked. A looser threshold could instead be pulling in mental health symptoms that resemble autism, or making the diagnosis a route to support in overstretched services. 

The conditions adults carried in their records before an autism diagnosis may offer clues to whether the profile of people receiving that diagnosis has changed. This population-based analysis starts to put data behind the shift to disentangle what it means. 

Adults newly diagnosed with autism had a different medical profile at the end of the study period than at the beginning, in both the UK and Sweden. In the UK, the proportion with a prior anxiety diagnosis rose to 58.3% in 2023 from 28.7% in 2010. Anxiety also became more common among matched adults without autism, increasing to 21.9% from 8.2%, suggesting a broader population trend. However, the absolute increase was substantially larger among those who later received an autism diagnosis.

Depression, attention-deficit/hyperactivity disorder (ADHD), sleep disorders, and prior use of antidepressants, melatonin, opioids, and gabapentin followed a similar pattern in both countries. Conditions and treatments that became more common among adults later diagnosed with autism also increased among matched comparison adults, although the absolute increases were consistently larger in the autism group.

Epilepsy, intellectual disability, and psychosis showed the opposite trend. In the UK, a prior epilepsy record among newly diagnosed adults fell to 4% in 2023 from 10% in 2010, while matched adults held steady, at 1.2% in 2023 from 1.3% in 2010. Prior records of intellectual disability and psychosis also fell in both countries, whereas matched adults showed no decline. 

The analysis included records from about 24.5 million UK adults through 2023 and 9.1 million Swedish adults through 2021. Each newly diagnosed adult was matched with up to four adults without autism by age, sex, and local practice or municipality. Researchers counted diagnoses and prescriptions recorded before the autism diagnosis, including those documented during the diagnostic workup. Findings rely on recorded diagnoses, drawn from primary care in the UK and predominantly specialist care in Sweden.

By the end of the study perios, about 4% of 16-to-20-year-olds in both countries carried an autism diagnosis. The authors suggest that diagnostic practice may have broadened beyond research criteria, though the data cannot rule out that more people with autism are now being identified. 

“While these data are unable to shed light on whether these changes indicate greater appreciation of nuanced forms of autism, or misdiagnoses of other psychiatric presentations as autism, efforts will need to be made to recognize and address the needs with appropriate support,” the authors write. 

Source: Sadik A, et al. (2026 Nov 3) BMJ Ment Health. Changes in the profile of adults diagnosed as autistic since 2010: population-based studies in the UK and Sweden