Editor's note: Carolyn L. Mears holds a research appointment at the University of Denver. She is the author of "Reclaiming School in the Aftermath of Trauma: Advice Based on Experience" and "Experiences of Columbine Parents: Finding a Way to Tomorrow." She speaks internationally about trauma recovery, crisis preparedness and school safety.
Denver, Colorado (CNN) -- Five a.m., Friday, July 20. I stumbled downstairs to make coffee, turned on the radio for the news. Suddenly, the peaceful morning was shattered by reports of a shooting in nearby Aurora, where a lone gunman went on a rampage in a movie theater. Twelve people were killed and many more injured. All who were present, or responded to the scene, or had loved ones there, have experienced a traumatic event. Even those who hear about the event and identify with the victims may feel traumatized.
I know firsthand what it's like to go through such a shock. My younger son was at Columbine High School on April 20, 1999, when two students attacked the school and murdered 12 students and one teacher. Our intense grief was compounded by horror that this had happened in our safe little community. We felt vulnerable and powerless. At the time, we all hoped important lessons would be learned that could prevent future incidents like it. But in the years since the Columbine tragedy, rampage shootings seem to occur with regularity. Unimaginable situations are now all too imaginable.
After the Columbine tragedy, I sought to learn what helped and what hindered recovery in the aftermath of trauma. This is what I can tell you from my own experience and from my work with others who have survived horrific experiences and gone on to reclaim their lives.
Right now, people will want to know how to prevent this kind of tragedy, accompanied by the anxious fear that "this won't be the last." Sympathy will ripple across the country for those who were affected. Survivors and those who lost loved ones will be supported in their grief for a while at least.
But over time, a traumatized population will be left on its own with the implied message: It's time to get over it and move on. They will struggle to do just that, assuming that they should indeed be able to get back to normal. But this sad, sad message only breeds frustration and anxiety.
Those who lost someone to the shooting will experience immeasurable sorrow at the willful violence that stole away their loved one and destroyed his or her future. Those who were injured will carry physical reminders of their trauma. And all who were at the theater during the attack will have enduring memories of the event. Feelings of vulnerability may be compounded by survivors' guilt as they struggle with why they escaped when others didn't.
People respond differently to traumatic events, and the rate of recovery is individual. As Columbine High School's principal Frank DeAngelis often says, "It's a marathon, not a sprint."
Trauma is a natural, biological response affecting all areas of function—psychological, emotional, mental, physical, and spiritual. Don't be surprised if you have intrusive memories and trouble sleeping, concentrating and communicating. Other responses include grief, fear, confusion, hyper-vigilance, withdrawal from friends, anger, risk-taking, memory loss and depression.
You may feel distanced from others who haven't experienced a trauma. Past relationships may be challenged as new ones form with those who were there during the shooting. You may become defensive and driven to reclaim a sense of power over what happens to you.
Get help. Telling your story to a trusted listener can help you work through your experience. Don't deny that you are affected by the tragedy. Let people help you. Tell them what you need.
Be alert to extreme response such as substance abuse, or rage, or suicidal thoughts.
Be gentle with yourself; allow yourself time to process all that happened. A gradual return to a familiar routine is helpful. Find relief in things that brought you joy in the past.
Above all, remember that recovery takes time. Don't assume things will go back to what was before. You have been changed -- as we all are by any unexpected life experience, but you may discover a greater appreciation for life and may treasure it more deeply.
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The opinions expressed in this commentary are solely those of Carolyn L. Mears.