Show me the Shakespeare play or the Renaissance essay that mentions pseudo-medical terms like "OCD" "PTSD" "paranoia" "depression" "psychosis" "neurosis" and others like them?
For that matter, show me the Ancient Greek play that mentions terms like these!
Show me a post-Enlightenment, pre-1850s work that does!
There is of course not one!
This wasn't because they went "undiagnosed" or hadn't been discovered; but because they did not exist then, do not exist now and cannot logically ever exist!
No behavior or misbehavior is a disease or can be a disease. That's not what diseases are!
The medicalization of everyday life is a recent and retrograde development!
In fact, whilst the human condition does not and cannot change as the Renaissance humanists believed - our culture has since then imensely degraded in some ways; and a greater understanding of human behaviour is probably gained by experiencing Shakespeare than by psychiatry text books!
I am sure there are young folk doing Literature A-Level or Bac at the same time as Psychology A-Level or Bac.
The contrast is probably quite stark between the two.
Between amazing literature from most of history before the last century or so that IN NO WAY mentions "mental illness" in the case of the Literature A-Level; and then between the Psychology one which is probably full of more recent and often more drab writings that most likely go on about NOTHING BUT so-called "Mental Illness" or "Mental Disorder".