I've been curious about catatonia, too. When my much older sisters were children my mom used to take them to Creedmoor (psychiatric hospital) to visit our great-aunt. She spent the majority of her adult life living in Creedmoor.

Anyway, my sisters remembered seeing catatonic people in the hospital. There were several.

I know that one reason why catatonia has dramatically decreased is because of the array of medications available nowadays.