The Biology of Soul Murder
Fear can harm a child's brain. Is it reversible?
By their appearances, the three little girls sitting quietly in molded plastic chairs in the psychiatric clinic of Texas Children's Hospital in Houston betray nothing of the mayhem they have experienced. No one would know that the night before, two armed men broke into their apartment in a drug-ravaged part of the city. That the children were tied up and the youngest, only 3, was threatened with a gun. Or that the men shot the girls' teenage sister in the head before leaving (she survived).
Yet however calm the girls' appearances, their physiology tells a different story. Their hearts are still racing at more than 100 beats per minute, their blood pressure remains high and, inside their heads, the biological chemicals of fear are changing their brains. "People look at kids who seem so normal after these experiences and say, 'All they need is a little love,' " says Bruce Perry, a child psychiatrist at Children's Hospital and at Baylor College of Medicine. But as Perry and other researchers are finding, trauma, neglect and physical and sexual abuse can have severe effects on a child's developing brain.
Tangled chemistry. Once viewed as genetically programmed, the brain is now known to be plastic, an organ molded by both genes and experience throughout life. A single traumatic experience can alter an adult's brain: A horrifying battle, for instance, may induce the flashbacks, depression and hair-trigger response of post-traumatic stress disorder (PTSD). And researchers are finding that abuse and neglect early in life can have even more devastating consequences, tangling both the chemistry and the architecture of children's brains and leaving them at risk for drug abuse, teen pregnancy and psychiatric problems later in life.
Yet the brain's plasticity also holds out the chance that positive experiences--psychotherapy, mentoring, loving relationships--might ameliorate some of the damage. Much remains unknown. But if scientists can understand exactly how trauma harms the brain, they may also learn much about healing broken lives.
Trauma's toll on a child's brain begins with fear. Faced with a threat, the body embarks on a cascade of physiological reactions. Adrenalin surges, setting the heart pounding and blood pressure soaring and readying the muscles for action, a response called "fight or flight." At the same time, a more subtle set of changes, called the stress response, releases the hormone cortisol, which also helps the body respond to danger.
Increasing evidence suggests that in abused or neglected children, this system somehow goes awry, causing a harmful imbalance of cortisol in the brain. In a study of children in Romanian orphanages, for example, Megan Gunnar, a University of Minnesota developmental psychobiologist, is finding that cognitive and developmental delays correlate with irregular cortisol levels.
Gunnar and others believe that excess cortisol leads to damage in a brain region known as the hippocampus, causing memory lapses, anxiety and an inability to control emotional outbursts. Cortisol and other brain chemicals also can alter brain centers that regulate attention, affecting a child's capacity to attend to words on the blackboard instead of a jackhammer banging outside.