Joker's diagnosis

After scouring some possibilities, I would conclude that the Joker would qualify for a diagnosis of antisocial personality disorder. The criteria for such are at least 3 of the following:

  1. Failure to conform to social norms with respect to lawful behaviors as indicated by repeatedly performing acts that are grounds for arrest. 

  2. Deceitfulness, as indicated by repeated lying, use of aliases, or conning others for personal profit or pleasure. 

  3. Impulsivity or failure to plan ahead. 

  4. Irritability and aggressiveness, as indicated by repeated physical fights or assaults. 

  5. Reckless disregard for safety of self or others.

  6. Consistent irresponsibility, as indicated by repeated failure to sustain consistent work behavior or honor financial obligations.

  7. Lack of remorse, as indicated by being indifferent to or rationalizing.

Source: http://www.psi.uba.ar/academica/carrerasdegrado/psicologia/sitios_catedras/practicas_profesionales/610_clinica_cuadrosfront_psicosis/material/dsm.pdf (page 2)

Joker certainly qualifies. Obviously, he repeatedly performs acts that are grounds for arrest. Second, he shows reckless disregard for anyone else’s safety, including his own men (#5), which ties in with a lack of remorse (#7). He isn’t a physically dominant foe, but has held his own in fistfights before (#6, kind of). Finally, especially throughout the comics and video games, Joker has taken on a handful of aliases and is adept at lying (#2).

Of course, Joker could also be classified as generally insane, as Rafter points out (she mentions protagonists, but in this context is can apply to any character) that some characters can be classified as insane simply based on their total lack of conscience, despite appearing charming and seductive at times. (p. 55)

Joker hints to Two-Face in the video clip that he doesn’t have a plan, but he must be lying. How else could he always be one step ahead of the Batman? Despite his questionable sanity, Joker appears to be smart enough for that. It is a good case to show how antisocial behaviour traits can influence criminality.