NEW YORK (AP) - Some admitted they had trouble sleeping. Others said they feared leaving the house. Most found their minds wandering back to images of burning towers and the horror.

Nine out of 10 New York City schoolchildren suffered at least one symptom of post-traumatic stress six months after Sept. 11, and almost 10 percent likely had the disorder, according to a study released Wednesday.

Mental health researchers participating in the report, which studied more than 8,000 children at 94 schools, were particularly surprised to find that children throughout the city - not just near ground zero - showed symptoms of several psychiatric problems.

"The school system, above all, has to be cognizant of the fact that they are trying to do a job with students who are very troubled, very troubled today because of 9/11," said Christina Hoven, a Columbia University psychiatric epidemiologist who led the study.

In the 1.1 million-student public school system, an estimated 75,000 children likely showed six or more symptoms of post-traumatic stress - enough to be diagnosed with the disorder, according to the Board of Education study.

Researchers said the study was groundbreaking in its comprehensive examination of children's response to a major disaster.

The study surveyed children in grades 4-12 in late February and early March, finding that 76 percent often thought about the terrorist attack, 24 percent had problems sleeping and 17 percent had nightmares. The study was based on questions posed to the children themselves.

Schools Chancellor Harold Levy said the study was a "wake-up call."

"That's powerful information for us to focus resources, and powerful information for us to focus the attention of the professionals so they keep their eyes out to pick out the kids who have this," Levy told reporters.

Fifteen percent of the children surveyed showed symptoms of agoraphobia - the fear of venturing outside the home. Hoven compared that with a 1996 study of several cities that showed about 5 percent of children on average suffer from agoraphobia.

The board of education study's agoraphobia findings suggest that an estimated 107,000 city schoolchildren suffer from the disorder after Sept. 11. Hoven said the fear could be heightened for children who travel through tunnels and over bridges to get to school.

"If they're scared of it, if they're worried about it, if it's distracting from their schoolwork, that's something that's of serious concern," Levy said.

Researchers said the study found that younger children, girls and those whose family members were at the World Trade Center - whether they were killed, hurt or unharmed - were more likely to suffer from psychiatric disorders.

Levy said the information would be used in several ways, including toward securing more federal funding for mental health programs.

"What this is telling us is that in some schools, we're going to have to do more," Levy said. "That could mean simply more hours or more guidance counselors, or actual more intense programs."

Copyright 2002 The Associated Press. All rights reserved.