In all sincerity, I think he has. I didn't see the episode of Oprah where he was hopping around (I haven't seen an episode of Oprah in 10 years or more), but I saw stills from it. He seemed pretty crazy.
I saw him in England where he was really furious and upset with those guys who through water on him. He looked INSANE when he was talking to them and threatening them.
I mean, he's suppose to be a big star and he was totally losing it over some bottled water!
Combine that with the "Pat and Kenny read Oprah transcripts" segment on Letterman, and you'll probably have a perfct understanding of the incident.