In the first draft of the script, the infamous "Pudding!" line and pants dropping act was done by Sam. However, when they went to shoot Jared Padalecki and Jensen Ackles, Sam and Dean respectively, changed it to Dean on the spot without telling anyone because they felt it fit his character better.
The aliases Sam and Dean use are Eddie and Alex. Eddie and Alex are the two brothers in the band Van Halen (Eddie Van Halen and Alex Van Halen, for whom the band is named). Yet another Supernatural tribute to classic rock bands.
This is the second time Sam & Dean have used the last name Babar, which is a direct reference to the Chevy Chase movie Fletch. They even use a quote from Fletch, when the Dr. asks if there is a children's book about an elephant named Babar & they reply that they don't have any elephant books.
As the episode ends, Dean says "let's get the hell out of here" and the boys get into the car and drive off. The car heads out down the road into the dark night and a strain of music plays very reminiscent of the Terminator 2 theme. (Which also plays in that movie as a car heads down a road in the dark). Terminator 2 also centres around a character who is placed in a mental institution because no one believes that what they are fighting is real.
When Dean says "quid pro quo Clarice" to his psychiatrist, Dr. Cartwright, he is quoting a line said by Dr. Hannibal Lecter from "Silence of the Lambs". Lecter said this to FBI cadet Clarice Starling when she wanted to interview him. The slurping sound Dean makes was also done by Lecter, in what is probably his most famous line. "A census taker once tried to test me. I ate his liver with some fava beans and a nice chianti."
The trivia items below may give away important plot points.
One of Dean's "real" crazy symptoms when he and Martin are fleeing the halls, is walking slow and stepping sideways to avoid the cracks in the tile, exactly like Jack Nicholson's Obsessive Compulsive character in As Good As It Gets (1997). This is the second Nicholson movie reference in this episode.