In the face of such devastation, so many shattered families and lost friends, how do we ever heal?
It will be a long hard road according to mental health professionals who are preparing, just as hospitals did, for an onslaught of casualties.
"People are scared, they're upset, they're anxious, they're depressed. They have problems with sleeping and nightmares, sometimes flashbacks," Dr. Jonathan Silver of Lenox Hill Hospital told CBS correspondent Elizabeth Kaledin.
Hardest hit will be rescue crews, eyewitnesses, and of course families of victims. Dennis Levi can't find his father, John. "It's hard to sleep just knowing that you're missing somebody," he said.
Betsy Parks is searching for her brother Robert, a bond trader at the firm Cantor Fitzgerald, with offices on floors 101 through 105.
"Last night rest was very difficult due to the fact that the thunderstorm woke me up," she said. "I was very concerned that if he's lying out there in that rain and in that weather that I don't want him to suffer any more."
Nearly every company headquartered in the Trade Towers has made counseling a priority. The Port Authority of New York and New Jersey had 2,000 of its 7,000 employees stationed there. Today Red Cross workers tried to help them cope.
Said grief counselor Kathy Kozub, "Many people are not ready to give up hope yet and we have to be very careful not to take that away at this point."
Doctors say normal responses to Tuesday's catastrophe might include insomnia, crying, anxiety, and fear.
Classic symptoms of post-traumatic stress disorder include nightmares, flashbacks, recurring memories, avoidance of people and places, and constant crying.
A concern among doctors is that people will try to ignore their feelings, not recognizing the signs that they need help.
"People are reluctant to seek help for what they feel are emotional weaknesses," said Dr. Silver.
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