Did computer addiction cause Columbine?

Eric Harris and Dylan Klebold went on a killing rage at Columbine High School in 1999 because they were abruptly denied access to their computers, an Oregon psychiatrist says in a published study.

The two young men relied on the virtual world of computer games to express their rage and to spend time, and cutting them off in 1998 sent them into crisis, said Jerald Block, a researcher and psychiatrist in Portland.

"Very soon thereafter - a couple of days - they started to plan the actual attack," Block said.

Block published his research in the current issue of the American Journal of Forensic Psychiatry, a peer- reviewed journal.

The paper is likely to generate debate, said Cheryl Olson, co-director of the Center for Mental Health and Media at the Massachusetts General Hospital.

Block sifted through thousands of pages of documents released by Columbine investigators and said he believes both Harris' and Klebold's parents banned them from their computers after the two were caught breaking into an electrician's van in 1998.

Harris and Klebold had each previously been temporarily kept off computers at school or at home, and after each incident, Block said, the boys' writings or behavior became more violent.

Block said he worries about people immersing themselves so deeply and also about cutting them off cold-turkey.

"How do you pull them out, without triggering homicidal or suicidal behavior?" he asked.