Well, actually it was Hannibal Lecter who was asked that question. But never mind.
Every so often, someone on House will comment that the title character is not simply a jackass, but actually insane. Cuddy & Cameron, in particular, have both commented that it’s insane to expect him to behave in a sane fashion; and you can often almost hear Wilson thinking, “Maybe I should just taser him and drg his ass to an asylum. The only people who’d try to stop me would be the people who want to kill him instead.”
But insane is a hugely broad, terribly imprecise term. Let’s diagnose Greg House, based on the information available. You can just say where you think he appears in the DSM-IV, or you can speculate on what traumas you believe led him to his current state.
High functioning drug addict, who needs to hold it together at work, and continue to look brilliant, to protect his source of drugs and reassure himself that he’s not really an addict and it’s okay to take drugs the way he does. But avoids other entanglements, lest it gets revealed that he’s got a problem.
I’m not a regular House watcher so I don’t think I’ve seen the full range of his behavior, but I’d be inclined to rule out Schizoid personality disorder as well as Asperger’s syndrome or any autism spectrum disorder.
House doesn’t seem to have any difficulty in communicating with other people or understanding their thoughts, feelings, and personal motivations. But rather than use his understanding to help him get along with others, he uses it to needle and insult them instead. House isn’t indifferent to the feelings of others, he deliberately tries to make them feel embarrassed and angry.
His drug problem is of course a major issue in and of itself.
He has Granny Weatherwax Syndrome: feeling superior to everyone else but constantly testing others in the secret hope of finding someone who will best him.
It’s really difficult to make any psychiatric diagnoses until the mood-altering drugs are out of the system for at least 6 months. Active addiction mimics many psychiatric disorders.