So, I didn't go all the way back, but doing a check through a Nexis search of news transcripts back through October, the first appearance of a talking head referring to Dean as "pessimistic" or discussing his "pessimism" was Laura Ingraham on the Friday Dec. 19 Hardball, followed by Mary Matalin on the Sunday Dec. 21 Meet the Press.
Look for it to be coming out of every Republican's mouth soon, and then it will increasingly creep into "objective" reporting. The process will go something like this. First, they'll quote Bush campaign sources describing Dean as "pessimistic." Next, they'll move onto Democratic campaign sources, often anonymous, describing Dean as "pessimistic." Next, they'll stop bothering getting the quote and just write things like, "Some have criticized Dean for his unappealing pessimism..." And, then, finally, process complete, campaign analysis pieces in print and the "objective journalists" on the roundtable shows, will just write/say things like "Dean's pessimistic rhetoric..." By the end no discussion or news story about Dean will see the light of day without the word "pessimism."
...Dec. 26 - Ollie North goes for pessimistic.