Thousands of children living in New York are struggling with mental problems related to September 11 that in many cases will last into adulthood, according to psychiatrists who studied the impact of the attacks.
As the anniversary of the attacks that killed 3,000 people approaches, the study suggests the mental health of a whole generation of young New Yorkers has been damaged, with problems like alcohol abuse and depression showing significant rises.
"For thousands of children this is an image, an experience that they carry with them for life...it's a whole generation," said Christina Hoven, one of the psychiatrists who conducted the study on around 8,300 New York children aged between nine and 18.
The children who took part in the study were assessed around six months after the attacks and either lost a relative in the World Trade Center or had one who escaped.
Hoven said the surprising aspect of the results was that the eight forms of mental illness, including depression, post traumatic stress disorder and alcohol abuse, were just as prevalent in children who were nowhere near ground zero as in those who had witnessed the attacks first hand.
"All of the eight disorders were quite elevated from what could be expected in the general population," Hoven said.
"We took the entire city and what was surprising was that rates around the city were quite similar so the important thing was not proximity to the disaster but age, with younger children being more vulnerable."
Haven and her colleagues at Columbia University are in Japan for the World Psychiatry Congress where they will present the results of their study on Tuesday.
She said many of the symptoms mirrored mental problems more often seen in war zones, which suggested that many of New York's 1.2 million children may be unaware of the mental scars they are carrying until later in life.
Another traumatic event, such as a car crash, could suddenly trigger a mental reaction in adulthood.
"We're talking about a very large population at risk," she said.
"We know enough about the effects of the ravages of war. They keep it a secret, they don't tell their children what they experienced. It's something you don't even want to repeat, but then suddenly there's a car accident and you relive it."
While the children had shown a similar reaction to their peers in war-torn countries, the study also found that New York's unique ethnic mix and its transport system made for important differences.
Many children of immigrants who had experienced trauma abroad are more vulnerable to September 11 related problems due to past experience.
The fact that so many children travel a long distance to school had also resulted in a sharp increase in agoraphobia, a fear of open spaces that is not normally associated with disasters.
Hoven said that on average, around three to five percent of children could be expected to suffer from the complaint, but the study had found levels at about 15 percent.
"In New York city, 750,000 children a day travel to school...agoraphobia makes a lot of sense because of the exposure of having to ride in these situations," she said.