Human cruelties stamp their victims' memories with a template that regards with fear anything vaguely similar to the assault itself. A man who was struck on the back of his head, never seeing his attacker, was so frightened afterward that he would try to walk down the street directly in front of an old lady to feel safe from being hit on the head again.2 A woman who was mugged by a man who got on an elevator with her and forced her out at knife point to an unoccupied floor was fearful for weeks of going into not just elevators, but also the subway or any other enclosed space where she might feel trapped; she ran from her bank when she saw a man put his hand in his jacket as the mugger had done.
The imprint of horror in memory—and the resulting hypervigilance—can last a lifetime, as a study of Holocaust survivors found. Close to fifty years after they had endured semistarvation, the slaughter of their loved ones, and constant terror in Nazi death camps, the haunting memories were still alive. A third said they felt generally fearful. Nearly three quarters said they still became anxious at reminders of the Nazi persecution, such as the sight of a uniform, a knock at the door, dogs barking, or smoke rising from a chimney. About 60 percent said they thought about the Holocaust almost daily, even after a half century; of those with active symptoms, as many as eight in ten still suffered from repeated nightmares. As one survivor said, "If you've been through Auschwitz and you don't have nightmares, then you're not normal."
HORROR FROZEN IN MEMORY
The words of a forty-eight-year-old Vietnam vet, some twenty-four years after enduring a horrifying moment in a faraway land:
I can't get the memories out of my mind! The images come flooding back in vivid detail, triggered by the most inconsequential things, like a door slamming, the sight of an Oriental woman, the touch of a bamboo mat, or the smell of stir-fried pork. Last night I went to bed, was having a good sleep for a change. Then in the early morning a storm front passed through and there was a bolt of crackling thunder. I awoke instantly, frozen in fear. I am right back in Vietnam, in the middle of the monsoon season at my guard post. I am sure I'll get hit in the next volley and convinced I will die. My hands are freezing, yet sweat pours from my entire body. I feel each hair on the back of my neck standing on end. I can't catch my breath and my heart is pounding. I smell a damp sulfur smell. Suddenly I see what's left of my buddy Troy . . . on a bamboo platter, sent back to our camp by the Vietcong.... The next bolt of lightning and clap of thunder makes me jump so much that I fall to the floor.3
This horrible memory, vividly fresh and detailed though more than two decades old, still holds the power to induce the same fear in this ex-soldier that he felt on that fateful day. PTSD represents a perilous lowering of the neural setpoint for alarm, leaving the person to react to life's ordinary moments as though they were emergencies. The hijacking circuit discussed in Chapter 2 seems critical in leaving such a powerful brand on memory: the more brutal, shocking, and horrendous the events that trigger the amygdala hijacking, the more indelible the memory. The neural basis for these memories appears to be a sweeping alteration in the chemistry of the brain set in motion by a single instance of overwhelming terror.4 While the PTSD findings are typically based on the impact of a single episode, similar results can come from cruelties inflicted over a period of years, as is the case with children who are sexually, physically, or emotionally abused.
The most detailed work on these brain changes is being done at the National Center for Post-Traumatic Stress Disorder, a network of research sites based at Veterans' Administration hospitals where there are large pools of those who suffer from PTSD among the veterans of Vietnam and other wars. It is from studies on vets such as these that most of our knowledge of PTSD has come. But these insights apply as well to children who have suffered severe emotional trauma, such as those at Cleveland Elementary.
"Victims of a devastating trauma may never be the same biologically," Dr. Dennis Charney told me.5 A Yale psychiatrist, Charney is director of clinical neuroscience at the National Center. "It does not matter if it was the incessant terror of combat, torture, or repeated abuse in childhood, or a one-time experience, like being trapped in a hurricane or nearly dying in an auto accident. All uncontrollable stress can have the same biological impact."
The operative word is uncontrollable. If people feel there is something they can do in a catastrophic situation, some control they can exert, no matter how minor, they fare far better emotionally than do those who feel utterly helpless. The element of helplessness is what makes a given event subjectively overwhelming. As Dr. John Krystal, director of the center's Laboratory of Clinical Psychopharmacology, told me, "Say someone being attacked with a knife knows how to defend himself and takes action, while another person in the same predicament thinks, I'm dead.' The helpless person is the one more susceptible to PTSD afterward. It's the feeling that your life is in danger and there's nothing you can do to escape it —that's the moment the brain change begins."
Helplessness as the wild card in triggering PTSD has been shown in dozens of studies on pairs of laboratory rats, each in a different cage, each being given mild—but, to a rat, very stressful—electric shocks of identical severity. Only one rat has a lever in its cage; when the rat pushes the lever, the shock stops for both cages. Over days and weeks, both rats get precisely the same amount of shock. But the rat with the power to turn the shocks off comes through without lasting signs of stress. It is only in the helpless one of the pair that the stress-induced brain changes occur.6 For a child being shot at on a playground, seeing his playmates bleeding and dying—or for a teacher there, unable to stop the carnage—that helplessness must have been palpable.
PTSD AS A LIMBIC DISORDER
It had been months since a huge earthquake shook her out of bed and sent her yelling in panic through the darkened house to find her four-year-old son. They huddled for hours in the Los Angeles night cold under a protective doorway, pinned there without food, water, or light while wave after wave of aftershocks tumbled the ground beneath them. Now, months later, she had largely recovered from the ready panic that gripped her for the first few days afterward, when a door slamming could start her shivering with fear. The one lingering symptom was her inability to sleep, a problem that struck only on those nights her husband was away—as he had been the night of the quake.
The main symptoms of such learned fearfulness—including the most intense kind, PTSD—can be accounted for by changes in the limbic circuitry focusing on the amygdala.7 Some of the key changes are in the locus ceruleus, a structure that regulates the brain's secretion of two substances called catecholamines: adrenaline and noradrenaline. These neurochemicals mobilize the body for an emergency; the same catecholamine surge stamps memories with special strength. In PTSD this system becomes hyperreactive, secreting extra-large doses of these brain chemicals in response to situations that hold little or no threat but somehow are reminders of the original trauma, like the children at Cleveland Elementary School who panicked when they heard an ambulance siren similar to those they had heard at their school after the shooting.