I don't know too much about what ailed Charles VI of France, Joanna of Castile, George III of Great Britain, or Henry VI of England, but they all seem to have been mentioned as suffering from madness. They may be others too. I remember one text cryptically referred to Henry VI as succumbing to the madness hereditary on his mother's side and then failing to elaborate, perhaps to create a notion his dad was a thoroughly solid chap. Was there great difficulty from misdiagnosis, with mental health in that period too poorly understood, or do we now have confirmation of their fragility and a better appreciation of what conditions (if any) really ailed these rulers.
A reply to /u/PlazaOne
I do not know much about the French, Scot, and English mental ailments but I am familiar with the "madness" that seemed to afflict the Trastamara dynasty and continuing to the Habsburgs in the early-modern era.
The most infamous case is perhaps that of Juana of Castille, that has earned her the moniker Juana la Loca or Juana the Mad. I wrote about her here. It seems to me that earlier historians tended to be very certain of themselves to prescribe "insanity" to Juana. After all, she gave very public displays of what sure looked like madness, including grieving over her dead husband's decaying body, and then refusing a call to rule Castille.
A little later on, historians started to write a romanticized view of Juana's history, focusing on the tragedy of her being married off to a foreign land, and living in a tumultuous time. Here's an example 19th century art depicting her grieving over her husband's dead body.
It's only recently that historians started to look at her more critically, questioning whether what she suffered was brought on by what amounted to mental abuse. In particular, there has been closer examination of the absence of any indication of mental illness until after she was shipped off to the Low Countries to marry Philip the Handsome.
Regardless of what exactly happened to Juana or what brought it on, it has been recorded that her maternal grandmother, Isabella of Portugal, also suffered from some sort of mental illness. And her maternal grandfather Juan II of Castille was also recorded as being brooding. Futher, her son Charles V was known to suffer from deep melancholy with increasing frequency as he grew older.
Charles V grieved for seven weeks when his wife passed away. Such was his grief that he retired to a monastery to grieve in private. His young son Philip II, aged 12, presided alone at the funeral obsequies of his mother. It was his first solo public appearance.
Charles' depression worsened toward the end of his life, in addition to his gout. The failed siege of Metz was a major loss both strategically and to his reputation. Some speculate that his irrational hastening of the siege was due to a form of PTSD and/or depression. It is known for sure that following that failure, he went to Brussels and locked himself in his quarters and refused to see anyone for weeks. His son Philip II had to catch up to him to help run the royal household and continue the negotiation of his abdication. He asked his brother to preside over the very important Diet of Augsburg in 1554-5. In the end, he abdicated and then retired to a Hieronymite monastery in Yuste, Spain.
I know that there are studies of the impact of inbreeding on the Habsburgs, for example here. But I'm not aware of medical studies of their mental health, and what seemed to be a hereditary disease.
