BOSTON, MA — Long-term studies of child development indicate that some people remain psychologically healthy despite years of severe deprivation and trauma. Researchers are now studying the characteristics and circumstances surrounding the ability to endure stress and bounce back—a quality they call resilience, reports the December 2006 issue of the Harvard Mental Health Letter.

Adapting to stress is a complex process that involves many interacting influences. Social and family environment have received most of the attention, but advances in genetics, psychopharmacology, and brain imaging now permit closer study of the biological underpinnings of resilience.

A promising line of research involves interactions between early experience and genetically determined neurobiology. Low levels of monoamine oxidase A (MAO-A), an enzyme that breaks down several neurotransmitters, have been linked to aggression in mice and humans. The gene that produces this enzyme has short and long forms, and the short form is less efficient. In a long-term study in New Zealand, maltreated boys with the short gene were more likely than those with the long variant to commit violent crimes and to score high on measures of aggressive tendencies.

If the neurochemicals are important, then so are the brain circuits in which they operate. Using brain imaging and other techniques, researchers are now looking at how the brain’s structure and function, as well as a person’s cognitive and neuropsychological characteristics, are linked to resilience.

"Clinicians once were inclined to assume that resilience in traumatic situations, especially chronic trauma, was exceptional and required special explanations," says Dr. Michael Miller, editor in chief of the Harvard Mental Health Letter. "Today, they are coming to understand it as an especially effective form of normal adaptation."