What Mental Illness Does The Joker Actually Have?

screenrant.com:

The Joker is well-known by comic book fans as Batman's insane enemy...but what specific mental illness does he actually possess? The Clown Prince of Crime has seemingly broken ever conceivable law in Gotham City, ranging from petty theft to mass murder on a metropolis-wide scale. All of his crimes are linked through his twisted sense of humor and his desire to play «jokes» on his victims — and therein lies a clue to the Joker's specific mental health illness (and whether or not he can actually be cured).

Diagnosing the Joker can be difficult because the character has changed drastically over time. His first appearance in Batman #1 depicted a criminal that showed little non-neural normal qualities. During the 50s and 60s, the Joker's crimes were limited to glorified pranks thanks to the draconian Comics Code Authority — and thanks to a rule stating that a criminal in a comic book must never get away with a crime, the Joker was arrested at the end of every issue (this cemented Arkham Asylum as an easily-escapable prison in the eyes of fans, perhaps damaging the CCA indirectly with every Joker story sold).

Related: Batman & Superman Are Too Dumb To Launch Their Greatest Team-Up Attack

Bipolar Disorder is a common diagnosis among fans; the Joker can indeed be possessed by sudden mood swings and anger — but that doesn't explain his propensity to murder (or show little to no remorse after the fact). Dissociative Identity Disorder (incorrectly described as Multiple Personality Disorder) is often brought up as well, but the Joker has rarely shown other personalities like the split that defines Harvey Dent and Two-Face. But one medical diagnosis describes the Joker's symptoms to a T: Witzelsucht.

Those who suffer from Witzelsucht