[JenB]

Don't most superheros have a trace of multiple-personality disorder? Superman, Spiderman, Batman, they've all got secret identities and alter egos... one could interpret the stories as the deranged concoction of diseased minds...

[Bear_in_RoseBear]

There's been some exploration of that theme in recent years, but most superheroes are seen as adopting a "secret identity" in order to protect themselves and their loved ones. Some, such as The Hulk and Rose and Thorn, are acknowledged to be true MPD cases, though.