Drenched with new experiences and neural changes, adolescents weather tumultuous years that may be the best time to study stress—and reduce it.
“Inhale it back!” instructs James, a fifth-grader leading his classmates in yoga postures.
On hands and knees while stretching his polo-and-plaid-clad torso, James pauses.
The next few seconds are positively breathless—and possibly transcendent. In withering afternoon heat, a dozen gangly kids perched catlike on purple mats unfurled atop the scuffed gym floor of a city school are calm and focused, respectful and balanced, belying the fact that all are teetering on the impulsive cusp of adolescence.
“Exhale it forward!”
Tamar Mendelson is breathing easy these days, having just been awarded a three-year $775,000 grant (with collaborator Mark Greenberg at Penn State University) to continue investigating the effects of a school-based mindfulness intervention involving yoga-based movement, much like the one James is now involved in. Ever since the Mental Health assistant professor reported positive results from a small stress reduction intervention in four Baltimore city schools, Mendelson has been gearing up for a more comprehensive study involving 270 fifth- and sixth-graders in six schools. Now, with new funding from the National Institute on Drug Abuse, that effort begins in earnest.
Her aim is to replicate data from the pilot study of 97 youth that showed mindfulness practices significantly reduced stress responses such as intrusive thoughts and emotional arousal. In addition, Mendelson will track long-term intervention effects by examining academic performance, neurocognitive abilities and other outcomes.
Mendelson, PhD, suggests the intervention (developed by Baltimore’s Holistic Life Foundation, Inc.) could serve as a much-needed buffer against not only the “normal” developmental stress of adolescence but also the traumatically chronic kind that weighs on kids from the inner city. In more affluent areas, privileged kids have their own stressors (and many more resources to cope with them). Regardless of locale, the fact remains: Adolescence is a badlands of stress.
The route from childhood to adulthood traverses complicated, often uncharted territory replete with slick slopes of emotion, hoodoos of hormones, and flash floods of physical and contextual changes, all of which demand risk taking and reward sensation seeking. Natural physiological changes necessarily drive young people toward new experiences —remember your first kiss? first car crash?—that are inherently stressful.
Emerging evidence from the field of neuroimaging and elsewhere has convinced a dozen or so Bloomberg School researchers that adolescence is an inordinately rich time to wrestle stress to the mat to reveal its underlying mechanisms—and perhaps the opportune moment to intervene.
“When you shape the coping skills of young adolescents, you can have a distal effect because you’re intervening fairly early in the trajectory of lifespan development,” says Mendelson. “You might expect lots of bang for the buck if you improve their ability to regulate emotions and thoughts. It could have major public health significance if kids stay in school longer, if they are less violent and rely less on drugs and alcohol to cope.”
Most traditional interventions involve educating adolescents about things they already know, according to Jay Giedd, chief of Brain Imaging at the Child Psychiatry Branch of the National Institute of Mental Health, and an adjunct professor in Population, Family and Reproductive Health (PFRH) at the Bloomberg School.
Adolescents are adept at what Giedd calls “cold cognition.” In a neutral environment like a classroom or the family dinner table, cold cognition allows them to explain all the reasons it’s important to wear a helmet when skateboarding and a seatbelt when driving; enables them to convince parents that they understand perfectly the perils of binge drinking and popping prescription painkillers. However, in the real world—in the context of high-emotion, peer-pressure situations—adolescents don’t take time to weigh consequences and calculate risk, Giedd says. “Hot cognition,” an entirely separate decision-making mechanism, isn’t altogether online yet. Lacking “hot cognition,” they just do it. They go. It’s how they’re built—like Ferraris, but without the brakes hooked up. The adolescent brain accelerates so smoothly—so naturally and magnificently—that not flooring it is the aberration.
“Adolescent brains are not broken or defective adult brains,” observes Giedd, MD, who has used functional magnetic resonance imaging (fMRI) technology to scan thousands of immature cerebellums and prefrontal cortexes-in-progress. “Rather, they are exquisitely forged by the forces of our evolutionary history to have different features compared to children or adults.”
Those “different features” result in part from the dynamic remodeling of neuronal circuitry that’s ongoing throughout adolescence. The brain streamlines and specializes during these years: Those connections used most often get more intricately grooved and deeply sculpted, while less-traveled pathways erode.
“When we began our studies, we thought that by age 16, the brain would be as done as it’s going to get,” says Giedd, a father of three teens and one pre-teen. “But we’ve seen that the changes clearly ramp up in adolescence—and stay ramped up in 18-year-olds, 20-year-olds, 22-year-olds and beyond.”
It’s a time of great changeability paired with great vulnerability—a recipe for stress if ever there was one, Giedd says.
“Stress is a big issue here,” says Freya Sonenstein, PhD, MA, director of the Center for Adolescent Health, referring to urban Baltimore. Among adolescents seeking jobs and GEDs at a city-sponsored Youth Opportunity (YO!) Center near the Johns Hopkins East Baltimore campus, a full 44 percent have symptoms of post-traumatic stress disorder.
Notably, stress-reactive mental disorders—anxiety, schizophrenia, eating disorders and depression, for instance—take off in adolescence, observes Catherine Bradshaw, PhD, a Mental Health associate professor and associate director of the Johns Hopkins Center for the Prevention of Youth Violence.
The scientific study of adolescence dates to 1904 when psychologist G. Stanley Hall pegged the transition years between childhood and adulthood as a bona fide developmental period—one characterized by “storm and stress.” Prior to Hall, observations from the reliable likes of Aristotle and Socrates describe those transitioning from childhood to adulthood as “heated by nature as drunken men by wine,” and note youths’ inclination to contradict parents and tyrannize teachers.
Though associated most with the teen years, adolescence is a moving target. Some say it begins at puberty and ends at 18; others contend 21, at which point—presto!—adulthood is magically attained. The Centers for Disease Control lumps 10- through 24-year-olds into this developmental stage, though Giedd’s neuroimaging evidence shows the human brain continues to remodel in important ways clear through the late 20s.
Every bit as ambiguously amorphous as adolescence is the concept of “stress.” It can mean anything from flunking a physics test to years of sexual abuse. Its downstream consequences include everything from mood disorders to heart disease.
In 1904, psychologist G. Stanley Hall pegged the transition years between childhood and adulthood as a bona fide developmental period—one characterized by “storm and stress.”
“If you look at stress as a demand that the brain needs to adapt to, and then, by virtue of adapting, it’s better at problem solving or memorizing or whatever skills matter, then the goal isn’t to eliminate stress but to get the right amount,” says Giedd. He proposes there’s likely a “sweet spot” of stress that’s unique to each individual, beyond which that person is either underwhelmed or overwhelmed.
Figuring out what to measure, as well as when and how to measure it, is a key question in stress research. Some investigators ask study subjects to document life events—in the recent past, have you lost a pet? witnessed a murder? had a child? started a new job?—in an attempt to quantify stress based on how many stressors individuals are exposed to, how often they happen and the nature of those stressors.
Others are more interested in how individuals perceive those stressors. Glass-half-full types who are good at reframing expectations and adjusting attitudes probably experience less stress than those who don’t have innate coping skills or haven’t learned any.
And increasingly, investigators are measuring stress by assessing its physiological effects on individuals.
“Imagine the body as a stress sifter,” says Sara Johnson, PhD ’05, MPH ’01, a PFRH assistant professor. “The size of the holes in an adolescent’s sifter depends on his coping resources and buffers. Forget what he thinks about stress, or what he remembers about it. What shakes out at the bottom is the stress that’s left; the stuff that gets past all the buffers, or lack thereof, is important because this is what affects developing biological systems.”
Douglas Granger shakes a plastic vial filled with spit. A psycho-neuroendocrinologist, Granger has much-sought-after expertise in collecting and analyzing saliva. He’s the go-to guy for behavioral researchers across the country who want to incorporate the biology of stress into their studies.
Spit, it so happens, contains a lovely assortment of chemicals, some of which serve as important biomarkers related to stress.
“Stress happens when the environment requires a person to adjust—something adolescents have to do all the time,” says Granger, PhD, director of the Center for Interdisciplinary Salivary Bioscience Research at the School of Nursing. “Adolescents have a ton of biological changes going on as they transition through puberty and at that same time, all these contextual changes. Sometimes those changes cause a person to alter how he behaves or thinks; other times, they activate his physiology.”
The body reacts in complex ways to new or challenging exposures or experiences—by activating the stress hormone cortisol, for instance—in order to help a person adjust. But if stress signals occur too often, at improper times, in great quantities, or over a prolonged period, they can wear and tear down minds and bodies.
To assess the psychobiological stress response, spit makes good clean sense. Saliva can be collected painlessly anywhere and anytime a stressful event or stress-reduction intervention is happening; in context, as scientists say, such as before and after taking an SAT test or yoga class, or discussing problems with a counselor or best friend.
Although the focus in the field traditionally was on measuring cortisol, known as the “stress hormone,” researchers increasingly are considering new biomarkers of stress reactivity; notably, the enzyme alpha amylase—a marker of the fight-or-flight response.
Jacinda Dariotis is investigating a “black box problem.” What’s happening in the gap between adolescents’ intentions and their behaviors?
Because people respond to stress behaviorally and biologically, investigators who consider only one kind of stress measurement may miss a vital part of the story. Whether an adolescent is aware of being stressed and how well he can coordinate behavioral and biological responses to stress are important bits of information that might have enormous therapeutic potential, adds Granger, a professor of Nursing, Medicine and PFRH.
As an example, he points to a research paper on which he recently collaborated. It challenges the popular opinion that it’s always a good thing for adolescents to discuss problems, revealing that biologically measured stress actually worsened when adolescents talked over their problems with co-ruminating peers. “There is real treasure in being able to assess the efficacy of interventions, to know what works best for whom and when,” he says.
The Bloomberg School’s Jacinda Dariotis couldn’t agree more. That’s why she’s turning to Granger’s spit lab for help investigating a “black box problem” among adolescents.
“There are intentions on one side and behaviors on the other and we don’t really know what’s going on between them; there’s a real disconnect for some,” says Dariotis, PhD, MAS, MA, MS, a PFRH assistant professor. “I’m looking for that missing link.”
She’s gearing up for a yearlong project in which she’ll be monitoring the risk-taking and substance-abuse behaviors among a sample of 100 inner-city 18- to 24-year-old males and females who are at risk for acquiring or transmitting sexually transmitted diseases. She’ll be collecting spit samples at four time points at the beginning of the study, and then again a year later, as well as using surveys, taking fMRIs (images) of brains and issuing random text messages that will query her subjects: Did you have sex in the past 24 hours? Use a condom? Take any illegal substances? Her neuroscience–social science perspective will incorporate aspects of her subjects’ biology, endocrinology, brain activity, attitudes, perceptions, behaviors, planfulness and goals.
“I don’t think the brain is all there is to it,” Dariotis says. “I’m really interested to see if testosterone levels are somehow predictive of sexual risk-taking behaviors.”
Testosterone and the stress hormone cortisol tend to be inversely related, but there are exceptions, she explains: Individuals chronically under stress may be high in cortisol and high in testosterone.
Curious about how a person’s perception of stress relates to his actual biology, Dariotis and Granger want to understand the mechanisms of stress—the biological processes underlying outcomes. “It’s all about finding out who’s at risk and who would benefit from intervention,” Dariotis says. “I’m planning more projects to look earlier in the lifespan, but I had to start somewhere, so I started with the riskiest time.”