Green’s Dictionary of Slang

(drugs) under the influence of crack cocaine.

1988		oral testimony in Lighter HDAS I.
1998		L. Stringer Grand Central Winter (1999) 129: When he was cracked up, he stalked the streets making a frightening spectacle of himself.
2000		W.T. Vollmann Royal Family 627: She was getting cracked up and paranoid.
2008		J. Niven Kill Your Friends (2009) 65: He was so cracked up and the music was so loud, that he didn’t hear the front door.