Autism diagnoses have surged dramatically in recent years, with figures in the UK showing an eightfold increase since 1998. Experts suggest this growth is not necessarily due to a rise in the number of autistic people, but rather a broader definition of what autism includes. Once focused on children with high support needs, the diagnostic criteria now encompass a wider range of traits, including those found in people previously diagnosed with Asperger’s and PDD-NOS.

This expanded understanding has led to greater recognition of autism in adults and women, two groups historically underdiagnosed. Girls, in particular, often mask their traits and were more likely to be diagnosed with mental health conditions in the past. Increased awareness and updated research have helped identify many previously overlooked cases.

The shift has also seen more adults receiving diagnoses, often with fewer support needs. Some see this as overdue recognition, while others worry that public understanding is being skewed by a focus on "milder" portrayals in media.

Though some speculate environmental factors may play a role, researchers like UCL’s Ginny Russell argue the rise in diagnoses is largely cultural. Changing perceptions and a wider net for diagnosis explain the boom, with genetics still seen as the main underlying cause of autism.