He does have a serial killer loner type vibe to him:

'Even cowboy actors get the blues. “Brokeback Mountain” star Heath Ledger says that when he first started become famous, he was wracked with insecurity. Seeing his face next to the slogan "He Will Rock You" on billboards for “A Knights Tale” didn't help matters.

“It freaked me out," he told the London Observer. “I was like, ‘What if I don’t rock ‘em?’” He turned down the role of Spider-Man. “I didn’t feel like I deserved it,” he says and described how he excused himself from the studio’s presentation and ducked into the men’s room. “And pretty much burst into tears. . . I was hitting my head, hitting the walls. It was a full-on anxiety attack.”'

MSNBC