The science of stress

Adolescence is a hard time for just about everyone. School pressure, changing relationships, craving the independence of adulthood while clinging to the security of childhood; it can all lead to a lot of emotional turmoil. But while the stress of growing up may be almost universal, how teens handle it varies wildly.

Data shows that poor reaction to stress can lead to the onset of mental illnesses and associated problems like substance abuse or antisocial behavior. In many cases, the first signs of these disorders surface when the person is feeling stressed. Research also shows that adolescents who have experienced trauma or adversity when they were younger, like the death of a close relative or abandonment by a parent, are more likely to have mental health issues triggered by stress, compared to people who have never faced that kind of hardship.

Even though there’s plenty of research linking stress and early adversity to mental disorders, there are very few studies looking at how the two are connected. Why does early life adversity or trauma make some people more prone to mental illness, especially when dealing with stressful situations? And if warning signs are identified early enough, can these problems be avoided? These are questions Boston Children’s Hospital researcher Kate McLaughlin, PhD, is trying to answer. McLaughlin, along with Margaret Sheridan, PhD, are analyzing how teenagers’ brains react to stress. The project involves over 200 adolescents, some with mental health issues and some without, as well as teens who have experienced early life adversity and others who haven’t.

The researchers hope that by examining how stress affects the brain activities of people from a wide range of backgrounds, they can better understand why stress is more likely to act as a trigger for mental illness in certain people. If behaviors and brain activity associated with stress-induced mental illness can be identified early, McLaughlin says they can also be treated early, sometimes even before a problem develops.

Stress test

Kate McLaughlin, PhD

To study how teenagers react to stress, McLaughlin and Sheridan expose participants to emotionally charged activities while monitoring their mental and physiological responses. In one session, participants are asked to count backwards, in sets of seven, from 856. If they slip up they have to start over from the top. In another they’re asked to give a speech to a handful of people about what it means to be a good friend, citing examples from their own life. At one point in the study they are taught a game, only to have the rules changed midway through to favor their opponent.

During these activities, researchers are monitoring their heart rate, blood pressure and other aspects of their physiology. Afterwards, participants answer questions about what they were feeling during the activity, and how they processed those feelings. All reactions are recorded, so researchers can pore over the data and look for patterns.

In a later portion of the study, participants are connected to electroencephalograms (EEGs) and functional magnetic resonance imaging (fMRI) machines, which monitor electrical activity in the brain. While their brainwaves are recorded, the teens are shown pictures meant to stir emotion, like a photo of a small child crying. At first researchers ask the participants how the images make them feel, and then ask them to try to reduce that emotional response as best they can. This exercise helps researchers better understand how people’s brains behave while processing and regulating strong emotion, and identifies brain patterns associated with positive or negative stress management.

By looking for similarities in the mental and physical reactions of the various participants—those with mental health concerns and those without—and comparing them to the level of adversity the person has experienced early in life, McLaughlin and team believe they can paint a clearer picture of how life experience and stress management are related. With the relationship defined, researchers can more easily identify positive mental and emotional responses to stress, and use the knowledge to help at-risk teenagers find better ways to cope with their emotions.

The road ahead

Like in football, a good defense is the best offense for healthy living. But when it comes to mental health, McLaughlin says preventive medicine is still very much in its infancy.

“Mental health disorders have very complicated origins. There’s not that one-to-one relationship you often see in physical health, like when studying how high cholesterol affects heart function,” she says. “As a result, we still have a lot to learn about how early interventions could help treat people before mental disorders develop.”

McLaughlin and Sheridan, along with Charles Nelson, PhD, research director of Boston Children’s Division of Developmental Medicine, will continue pushing this developing research forward, with hopes that their work will provide the groundwork needed to create preventive interventions that will reduce or eliminate the development of mental illness in thousands of young people.

“By better understanding the mental pathways that link life experience to later onset of mental illness, we can do a better job of targeting how and when we intervene,” McLaughlin says. “If done correctly we could keep many at-risk adolescents from ever developing mental health issues at all, sparing them from a lifetime of problems.”

To learn more about Boston Children’s Stress and Development Laboratory visit their website.