UNDATED (WHDH) -- An expert on the criminal mind says in some ways Holmes fits the profile of a mass killer.

For one, he recently had a big loss in his life; he was rejected by the University of Colorado’s PhD program, and he has isolated himself. But in other ways, he's not at all typical, and may have severe mental illness.

“He looks a little crazy in the court room. You know, he’s oblivious or he’s nodding off. I think there’s some possibility that Holmes in schizophrenic,” said Prof. Jack Levin, Northeastern University.

James Holmes' court appearance in Colorado has experts watching his every move. He appeared dazed, struggling to stay awake.

“Holmes is much younger than the typical mass killer who is a middle-aged guy who is sliding downhill fast,” Levin said.

And Jack Levin, a veteran criminologist who has studied mass killers, says Holmes may well believe he's a comic book villain.

“Someone who is psychotic might really believe he was the joker and might really believe that the people he killed were not victims, but villains,” said Levin.

Levin notes Holmes went to so much effort to booby-trap his apartment and then warned police there were explosives there.

“That contradictory kind of behavior is the hallmark of someone who suffers from psychosis,” Levin said.

As prosecutors try to decide whether to seek the death penalty, it's pretty clear what strategy Holmes' public defenders will use.

“I'd be shocked if the insanity defense were to work for him. The jury won’t buy it,” Levin said.