I have twin cousins who have severe autism, one of which is institutionalized. When they were very young we (their caregivers, family, and doctors) understood t

I have twin cousins who have severe autism, one of which is institutionalized. When they were very young we (their caregivers, family, and doctors) understood their diagnosis to be "mental retardation." Nowadays they are known as autistic. They didn't change, but the world around them changed so their diagnosis shifted. Before there were government services families still had children with profound disabilities that required lifelong care, they just didn't usually have any formal diagnosis. Everyone still understood that they need help with everyday activities and can't live on their own but sending them to specialist for a diagnosis didn't seem like something that was needed or even available if desired. The diagnosis is needed if you're applying for services, so more services that exist means more formal diagnosis will happen.