While researching lunatic asylums for my book about Blackwell’s Island, I came across a brief reference to what I thought was a very bizarre case. “A little girl, three years and four months old, evincing unequivocal symptoms of mental disorder, was admitted in the early part of the year. The mental disorder was recent. This case, so interesting on account of the age and mental peculiarities, still continues under treatment.” That’s all it says. There are no details or descriptions of the disorder. But it comes from the Pennsylvania State Lunatic Hospital in 1853, from the notes of Dr. John Curwen, Superintendent.
At first I got all judge-y about about diagnosing a toddler, and of course it was a little girl vs a boy. But apparently toddlers aren’t diagnosed enough, under the mistaken belief that children don’t develop disorders that early. According to the article in that link, they can.