"I started to get panic attacks," Underwood wrote last September on his blog. "I'd skip class and just sit in my car for hours, or sit in the library, in the stacks where there weren't any people, and read."
In the Sept. 8 posting, he also wrote he was becoming more and more detached from the world over the last year.
Underwood described himself as walking around "like a zombie" whenever he left his apartment.
"It gets worse every day," he wrote. "I withdraw farther and farther into myself with each passing week."
Several postings are about sex; he describes his own, limited experience in one posting. Others are news accounts from around the world of odd events or tragedies, including a mass murder in California.
Underwood repeatedly filled out quizzes about himself. He wrote in October 2004 that he was most afraid of "real ghosts and the thought of being abducted by aliens."
In answers to another quiz in August 2004, he wrote: "I'm not really religious at all, but the few beliefs I do have are a complex mix of at least a dozen different religions and cults."
Another question on the August 2004 quiz was: "Killed someone in your thoughts?" Underwood responded: "Constantly."
He also wrote about his interest in comic books, computer games and cartoons.
In some of Underwood's earliest postings in 2002, he wrote about reading novels on vampires over and over.
Just before the first anniversary of the Sept. 11, 2001, terrorist attacks, Underwood wrote how he didn't care about the deaths.
He wrote: "The same thing happened with the Murrah Building bombing ... I didn't care about that, and I don't care about the WTC. No one I know was involved in either of them, no one I know was hurt. And as long as none of my close friends or I are hurt, I don't give a ... how many people the terrorists kill."