Nearly three in ten kids attending New York City public schools appeared to develop at least one mental disorder following the September 11 attacks on the World Trade Center, according to new study findings released Monday.

The most common disorder was agoraphobia, or fear of public places, followed by separation anxiety and Post-traumatic Stress Disorder.

Not surprisingly, kids who had more direct exposure to the incident - such as being caught in the attack or extremely worried about a loved one - were more likely to have every type of disorder.

However, children whose family members were hurt or caught in the attack were more likely to have a mental disorder than children who were directly exposed to the incident themselves.

Study author Dr. Christina W. Hoven explained that, from a child’s perspective, this is not a surprising finding. When you’re little, “your world is really your parents,” said the researcher, based at the Columbia University Medical Center in New York. And if a parent is hurt, a child’s world is “shattered,” she said.

Many of the children involved in the study were nowhere near the World Trade Center, Hoven noted, but if their parents were involved, so were the children. “In this case, all of the children in New York City need to be thought about,” she said.

For the study, Hoven and her colleagues interviewed 8,236 students in the 4th through 12th grades attending New York City public schools, six months after the September 11, 2001 attacks that leveled the World Trade Center.

The researchers screened children for Post-traumatic Stress Disorder, depression, Generalized Anxiety Disorder (GAD), separation anxiety, panic, and agoraphobia.

Approximately 29 percent of students had at least one of these disorders, the researchers report in the Archives of General Psychiatry. Girls and students in the 4th and 5th grades appeared most at risk.

Children who had already experienced a traumatic event in their lives were doubly likely to develop a mental disorder following the September 11th attacks. In an interview, Hoven explained that a previous traumatic event leaves an individual more vulnerable than before, so that problems are more likely to arise when an additional trauma occurs.

Consequently, every New York City child, because of September 11th, is now at a higher risk of developing problems from any later event, she added. “All of them became at an elevated risk,” Hoven said.

Interestingly, children who attended schools near the scene of the attack were less likely to develop a mental disorder. These children, because of their obvious connection to the attacks, received a great deal of help in the subsequent months, Hoven explained. Encouragingly, this finding suggests that the interventions made a difference in these kids’ lives, she said.

SOURCE: Archives of General Psychiatry, May 2005.