This were the writing skills of a random dude who was stuck in an asylum. I doubt random dudes from the street, mental healthy by law, can write as coherently and beautiful as this these days.

Random dudes in those days couldn’t either.

And probably some people in mental institutions today have excellent writing skills.

Earliest I could find was this, which appears to me to be clearly fiction, and certainly doesn't use the framing device of an asylum inmate: https://archive.org/details/sim_harpers-weekly_1898-09-03_42...