It's often the last thing we think of when we hit the pillow at night. And the first thought that pops into our head in the morning.
It's the topic, wherever we turn. In the elevator at work. In e-mail messages. On dozens of television networks and talk shows.
We all share the same visual images: the second plane heading for the World Trade Center, the black smoke billowing from the twin towers, the pile of gray rubble hiding victims' remains.
Eleven days after the attacks on the World Trade Center and the Pentagon, television sitcoms, game shows and major league sports have all returned to America. Do they work as some kind of escape from the haunting images, or aren't we paying any attention? Do we really want to let go and get back to "normal?" And how long will it take?
There is no timetable for normalcy to return, experts say. And everyone, presumably, will have a different timetable.
"I think that, in many ways, we're going through what is essentially a grief reaction to a loved one's death," said Michael Weiner, Erie County mental health commissioner.
This time, the whole nation is mourning. And many people are experiencing the kind of post-traumatic stress that haunts Vietnam veterans and rape victims, experts say.
"I think this event was of such magnitude that it's off the charts for people knowing how to react," said Thomas T. Frantz, associate professor of counseling psychology at the University at Buffalo. "Right now, I think we're largely in the middle of reacting and trying to figure out what went on."
There's another component here -- the fear that this tragedy isn't over, that more lives could be lost.
Experts say there's nothing abnormal about still feeling depressed or profoundly sad.
More than seven of every 10 Americans claim they experienced some depression during the first week following the terrorist attacks, according to a poll by the Pew Research Center for the People and the Press.
Almost two weeks after the events, feelings of shock, disbelief and denial may be yielding to other thoughts and emotions: Anger at the hijackers and their supporters. Concerns about personal security. Overwhelming sadness. Survivors' guilt. Outright fear -- "could I be next?"
"After the shock wears off, people are going to react very differently to the traumatic events," Weiner said. "Some will become irritated or depressed. Others will have nightmares or lose sleep. Others may deny their feelings or blank out the event entirely."
But experts realize the profound effects may not be seen for weeks, months -- even years.
Many people still can't get away from CNN, NPR, Brokaw, Jennings or Rather, no matter how hard they try. The Pew study found 96 percent of the American public paying "close attention" to the story.
Some of us have seen the second plane slam into the South Tower more than 100 times. It's an image we can't erase.
"I still think there's a need to assimilate the gravity of (6,000) people who died (in New York City)," said Howard K. Hitzel, a clinical psychologist who heads a local community mental health center. "It's hard for us to understand what that really means."
People understand it when two people die in a car wreck. But 6,000 innocent people going to work one day and dying? In the United States of America? That may be too hard to process.
It may be why we can't let go of the visual images, the images of destruction and death.
"Those were extremely powerful images that we'll be living with for some time," said Hitzel, executive director at Lake Shore Behavioral Health.
Camping in front of the television set all night to learn more about the terrorist attacks makes sense for several reasons, psychologists say.
Learning more about what happened -- and why -- can help ease our fears.
"Information reduces the amount of the unknown," Frantz said. "There's an urgency to grasp information, because that will reduce the fear."
Media coverage provides another connection for people, especially for those whose coping mechanisms aren't ready to take over yet.
That's the same reason candlelight vigils and church services have become so popular.
"We need to be with other people, to be connected, to feel safe," Frantz said.
Psychologists even have an explanation for all the flag-waving and patriotism. In times of urgency, we return to symbols of comfort: to our family and our love of country.
"Patriotism is safe, it's definite," Frantz said. "The United States of America, the flag. It's a symbol of safety and security, something you can count on."
Many people feel torn about letting go of their near-obsession with the tragedy. Is it fair to turn on a ball game or a TV drama to get away from all this, when the victims never can escape it?
"We are really ambivalent," Hitzel said. "On one hand, we're so captivated about this event and don't want to step away from it. On the other hand, we need a break. We're tired. This has been extremely draining."
Weekday afternoons aren't exactly crunch time at local movie theaters. But Thursday afternoon, it seemed quieter than usual; only a trickle of people walked in or out of the Regal Cinemas on Elmwood Avenue -- and most were employees.
No way to escape
A handful of moviegoers interviewed there weren't looking for a two-hour escape. Instead, they were just getting on with their lives, nine days after the attacks.
Getting on with their lives but not forgetting what happened.
"There's no way you can escape it," said Bert Stewart, 24, of North Tonawanda, who was going to see "The Others." "You can watch a movie for two hours, and then you get out and it's still in your head. You can't turn your back on it."
Some moviegoers seemed tired of the constant television coverage, especially with its repeated visual images of the attacks.
"I'm kind of tired of seeing the plane (slam into the building) over and over again," said Andrea Grover, 24, a bartender from Buffalo. "I want to see what they're doing about it."
"I have to turn it off sometimes, because it gets me too upset," said Janice E. Franke, 65, who lives on the West Side. Last week, Franke would wake up in the middle of the night thinking, or dreaming, of the terrorists. She's gotten past that now, trying to think more positive thoughts.
But she can't ignore it all: "This isn't a bad movie. This isn't a nightmare. It's real."
To varying degrees, much of the nation is battling its own "post-traumatic stress disorder."
Mental health experts have labeled terrorist attacks as one cause of the disorder, which strikes war veterans, witnesses to multiple shooting deaths and anyone experiencing extreme emotional trauma.
Psychologists fear the effect of the terrorist attacks on anyone still dealing with unresolved grief, including those still battling through previous trauma.
"People who feel vulnerable or who had instances where they felt out of control or hurt could re-experience that trauma," Hitzel said.
And you didn't have to be at ground zero to feel that trauma.
Even sitting at home, watching the attack footage over and over, can produce a level of trauma for some people, Hitzel added.
A long time to heal
Obviously, the experts say, people will find their own way, their own timetable, to grieve and cope with their emotions.
For many, it won't be quick.
"There's so much emotion that people can't step away from it yet," Hitzel said. "It will be a gradual process. I think there will be an extended period of grieving -- weeks at minimum -- depending on how connected people are to the event."
Even for those who haven't felt depressed, the events may have taken a more subtle toll, evidenced by a quick temper, sleepless nights or pure exhaustion.
But it's hard to turn off this spigot.
"The event and the images are so unsettling that it creates a lot of anxiety and fear for all of us," Hitzel said. "That makes it very tiring. It's such a disturbing image, and it wears us out."