The Joker’s madness varies in intensity from comics, to television, to film.

Cesar Romero’s light-hearted performance in the original television series gave way to Jack Nicholson’s more mental, but still fairly silly portrayal, of the Joker in Tim Burton’s 1989 film, “Batman.” The version of the Joker in the comic “The Killing Joke,” from which the latest Batman film will draw, is a decidedly more sinister character.

In “The Dark Knight, the villain will be played by the late Heath Ledger, and the Joker seems hell-bent for blood. Where Nicholson often flashed wide, teeth-baring smiles underneath his clean, white makeup, Ledger’s gory face paint surrounds a grizzled, tight-lipped smirk. What results from this portrayal could be a superbly multidimensional villain.

Director Christopher Nolan has created opportunities for riveting performances by his cast with past films. Guy Pearce’s role as a tortured amnesiac in “Memento” stands out, but characters in “Insomnia” and “The Prestige” also show examples of how everyday stress leads people to destructive behavior. This trend will translate well into the story of the Joker’s origin.

But this begs the question: How are we to appreciate Ledger’s performance in light of the events that allegedly resulted from it? Ledger commented in an interview with The New York Times that playing the Joker was costing him sleep, and he was using the sleeping aid Ambien. It seems like the part took a serious mental toll on him. After he was found dead, the Associated Press reported the cause of death was an accidental overdose of sleeping aids, anti-anxiety perscriptions and antidepressents.

So, faced with the possibility that playing the Joker partially led to Ledger’s accidental overdose, what should we make of his final role? After his ground breaking and controversial performance in “Brokeback Mountain,” will this be the character Ledger is remembered for years from now?

Of course, it’s too soon to tell, but if Ledger makes the Joker as moving and intense as comes off in the trailers, this may be his most memorable performance. And though it is a darker role, it could still be an outstanding achievement.