Insanity

"Mental that one, I'm telling you."

- Ronald Weasley.

Insanity, also known as madness, is a general term for certain abnormal behavioral patterns, typically associated with those suffering from mental illness. Those suffering from insanity often cannot interact with normal society, and often need long-term treatment in a medicial facility such as St. Mungo's Hospital for Magical Maladies and Injuries. Prolonged exposure to certain curses, such as the Cruciatus Curse or the Imperius Curse, may cause this condition. It can also be inflicted by certain types of potions, either temporarily or permanently, such as the Drink of Despair and possibly Essence of Insanity. Listening to Fwooper song for a sufficently long period can also cause this condition.

Known insane individuals

 * As Uric the Oddball is known to have listened to Fwooper song for several months non-stop, as well as to have engaged in various eccentric behaviours, he was most likely insane.
 * Frank and Alice Longbottom were driven insane due to prolonged exposure to the Cruciatus Curse by Bartemius Crouch Jr. and the Lestranges. They were interred permanently in the Janus Thickey Ward of St. Mungo's Hospital for Magical Maladies and Injuries, and no longer seemed to recognize their son.
 * An old Muggle tramp Harry Potter saw when shopping with the Dursleys apparently was insane, as he was talking to a person who was not there.
 * Bartemius Crouch Sr. became insane after continual usage of the Imperius Curse on him by his own son. When Harry Potter and Viktor Krum found him on the edge of the Forbidden Forest in 1995, he wildly shifted back and forth between coherence to his surroundings, and believing it was several months earlier and he was dictating instructions to his assistant Percy Weasley.

Appearances

 * Harry Potter and the Goblet of Fire
 * Harry Potter and the Order of the Phoenix
 * Harry Potter and the Half-Blood Prince
 * Harry Potter and the Deathly Hallows
 * Fantastic Beasts and Where to Find Them