Images of earthquakes, hurricanes, and floods can be horrifying, and many people who escape such disasters are undoubtedly traumatized. But despite all they have endured, the good news is that many of these survivors will probably bounce back fairly quickly.

In the past decade, a lot of attention has been focused on post-traumatic stress disorder, which can disrupt sleep, cause recurrent nightmares and emotional instability, make concentration difficult if not impossible, and haunt a survivor with flashbacks.

But in the concern over those who suffer from traumatic symptoms, the power of human resilience may have been overlooked. Research shows that most of us actually rebound rapidly from trauma and loss, even when it is shocking and severe.

Overall, only 8 to 20 percent of people exposed to a potentially traumatizing event develop PTSD. Even among the emergency response teams and recovery workers at the World Trade Center site, the numbers were fairly low. According to the Centers for Disease Control, about 13 percent had symptoms that would qualify for a diagnosis of the stress disorder.

Psychologist George Bonanno, an expert in resiliency and grief, has found that continued stability and relatively healthy psychological functioning is actually the most common response following a harrowing experience.

Immediately after enduring an ordeal such as the death of a spouse or escape from a terrorist attack, many people have distressing feelings, find it hard to concentrate or have trouble sleeping. "When people are exposed to potentially traumatic events, most are shaken up and experience stress reactions—their physiological processes are activated, they may be in a state of hypervigilance and arousal, or they may be stunned and numb," says Bonanno, an associate professor of clinical psychology at Columbia's Teacher's College. These responses are normal.

But for most people, these symptoms fade away within a few days or weeks. The majority either have no significant coping problems or they struggle to cope for a brief time before recovering. "They may have their ups and downs, but they can still function," he says. In one of his studies of middle-aged widows and widowers, Bonanno found that more than one-half experienced few symptoms of traumatic stress, and these did not persist.

It's important to remember that this research is focused on significant problems that interfere with normal life, such as finding it impossible to enjoy the company of friends and family.

Directly after experiencing a major trauma, even very resilient people generally feel powerful emotions of sadness, anger or fear. In fact, there's some evidence that experiencing these emotions in the immediate wake of a trauma may pave the way for a more robust recovery.

Yet for most of us, these strong feelings don't make it impossible to work or relate to friends and family. And they don't interfere with our capacity for joy and fulfillment.

No one is sure yet why some people struggle with post-traumatic stress and why others cope much more easily. Personality may have a lot to do with it; optimists tend to cope somewhat better, as do those who are flexible in the face of change.

At some point in life, most of us will endure at least one potentially traumatic event, such as a life-threatening accident or the loss of a close relative. For those times when we are at a loss to help someone who has recently gone through a trauma, Bonanno has a few suggestions:

• Reach out to survivors. People with strong social support tend to cope better after a disturbing experience.
• If the survivor doesn't want to talk much about what happened, don't force him to spill his guts. "Let them talk about it if they want to, be quiet if they want and move on when they want," says Bonanno.
• Don't shy away from smiles or laughter. It's not disrespectful to show a sense of humor, and it may actually be a relief for the survivor.
• If the survivor is a friend, be aware that they may look to you to take a break from thinking over the experience. Bonanno's research on bereavement shows that survivors often prefer to mull over the death in private or with family and to talk about other things with friends. "Friendships are a way to have the other parts of life continue on," he says.