Autism became recognized as a developmental disorder distinct from schizophrenia for the first time by the WHO, in 1978.

Ever since Autism was recognized as a distinct disorder, researchers and doctors began to include other disorders and behaviors (that have long been studied in children) into the "autism umbrella".

Awareness of autism in the public culture increased with the release of Rain Man (1988) and other media portrayals.

The DSM-IV TR (an autism test deployed in year 2000) contained an almost complete rewrite of the definition of Asperger syndrome. Notably, it now no longer included speech and language difficulties. This greatly increased the number of people deemed to have the condition.

You can read more about the history of Autism here: https://en.wikipedia.org/wiki/History_of_autism

If you've read this far, its probably because you have a hyperfixation and you might be autistic. /s

Take the Free RAADS-R Autism test here: https://embrace-autism.com/raads-r/#test