Donnie Darko and madness in relation to morality

While madness has certainly been an element or subtext in many of our texts (J and H, INCB, “Bloody Chamber”), Watchmen and Donnie Darko discuss this issue more directly than most.  Consider the role of madness in one or more of these texts.  What argument about madness is being made?  About the relationship between madness and villainy, or madness and morality?  What kind of alternative moralities have been presented, and what do they suggest?