Sources told 9NEWS that Holmes made three attempts at harming himself but described them as "not aggressive."
The first time, Holmes stood on his bed and tried to hit his head by falling backwards. During the second attempt, Holmes ran across his cell to hit his head on the wall. During the third attempt, Homes hit his head on the wall.
After the three incidents, Holmes was transported to the hospital with unknown injuries. He was back in his cell Wednesday.
Defense lawyers say Holmes' condition prevented him from attending a court hearing scheduled for Thursday.
Court documents filed Wednesday didn't give any details on Tuesday's incident. The documents said only that Holmes' condition "renders him unable to be present in court for (Thursday's) hearing."
9Wants to Know learned if Holmes would have appeared in court for Thursday's scheduled hearing, there wouldn't be any visible injuries.
"It's not as simple as a migraine, and not something I think we'll resolve by morning," an attorney for Holmes said.
The defense asked the judge to postpone the hearing, which was scheduled to discuss pretrial motions and media requests for information under state open records laws.
The hearing has been continued to Dec. 10.
The 24-year-old Holmes is charged with killing 12 people and injuring at least 58 by opening fire in a crowded theater on July 20. He's being held without bail and hasn't entered a plea.
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(KUSA-TV © 2012 Multimedia Holdings Corporation with The Associated Press)