The Science of Resiliency

How do people maintain resiliency during stressful experiences? There’s no simple cure for the high rates of depression and burnout reported in recent studies of U.S. physicians, residents and medical students. But researchers who study stress and the brain say resiliency can be taught.

At the HMS Academy’s Seventh Annual Symposium on the Science of Learning on April 1, about 100 faculty members heard presentations on the topic of “Resiliency and Learning: Implications for Teaching Medical Students and Residents.”

“Understanding the neurological and psychological consequences of stress on learning and personal growth, good and bad, is critical as we work to optimize physician education,” said ­Richard Schwartzstein, director of the Academy, which works to advance medical education throughout the HMS community. Schwartzstein is the Ellen and Melvin Gordon Professor of Medical Education at Beth Israel Deaconess Medical Center.

Bruce McEwen, a professor of neuroendocrinology at the Rockefeller University, described evidence that brief episodes of acute stress can enhance memory and learning, while chronic, high levels can damage the mammalian brain.

Drawing on work with children and adults, George Everly, an associate professor of psychiatry at Johns Hopkins Bloomberg School of Public Health, plumbed the psychological roots of human resilience. Both he and McEwen cited a network of social support and faith in a higher power or purpose as key to bouncing back from trauma and intense, prolonged stress.

Linking the nervous and endocrine systems, biochemical mediators regulate the effects of stress, which are exacerbated by health-related behaviors such as inactivity or poor diet. Under acute stress—think “fight or flight”—the hypothalamus churns out corticotropin-releasing hormone, prompting a sharp rise in the stress hormone cortisol, which enhances immunity, memory, energy and cardiovascular function. Once the stressor has passed, the hormone DHEA, neuropeptide Y and other biochemicals rush in, restoring equilibrium and easing symptoms, such as hypertension. Acutely, these mediators, along with emotional engagement with a task, may enhance learning.

But when stress is chronic, cortisol erodes health. Immune suppression, hypertension, bone mineral loss, muscle wasting and metabolic disorders ensue. Within the hippocampus and amygdala, seats of memory and emotion, dendrites shrink and synapses vanish, McEwen has shown. Cognitive function declines, depression sinks in, the immune system weakens, and metabolism goes awry. In a study of medical students preparing for board exams, McEwen’s collaborators found that higher levels of perceived stress predicted poor mental flexibility and reduced functional connectivity in the prefrontal cortex.

The good news: These ill effects are reversible, McEwen said. Regular exercise returns the hippocampus to normal size and improves memory, for example, while mindfulness training reduces the amygdala’s volume and curbs anxiety. Many adult diseases could be prevented by reducing toxic stress in utero and in early childhood, he said.

In the wake of war, natural disasters and severe abuse, 15 to 20 percent of those affected suffer from post-traumatic stress disorder. By focusing on the rest, including Navy SEALs and other stress-hardy groups, Everly has identified distinct attributes. The best predictor of immunity to stress, he said, is a social support network. Optimism (including faith in a higher cause or power), perseverance (work ethic), responsibility and integrity also count.

As for why some people sink instead of swim, Everly emphasized two factors: A lack of perspective—stemming from inadequate preparation and tenacity—and a negative attitude.

Resilience can be taught, said Everly, who also directs the Resiliency Sciences Institutes at the University of Maryland. First, let people experience success: Assign them to a successful group. Second, create a surveillance system and safety net, and provide encouragement, mentoring and training. Finally, mitigate the impact of stress by promoting “self-efficacy”—the belief that we are agents of change. Everly noted, however, that one cannot “give” self-esteem; it must be earned through personal accomplishment in the face of a challenge. Calling for a cultural shift, he said, “We must reframe mistakes as opportunities for learning.”

Click here to read a conversation with HMS psychiatrist Laurie Raymond about stressors among medical students and the support network that aims to help them be successful.