Early trauma may shape how children’s stress responses relate to anxiety and behavioral problems, according to a study published in Development and Psychopathology. Among youth who experienced potentially traumatic events before age 6, a smaller cortisol increase during a social stress task predicted a shift over the next two years toward externalizing symptoms rather than anxiety, while a larger increase predicted a shift toward anxiety.
Cortisol is a hormone involved in the body’s response to stress. It can rise when someone faces a challenge, such as speaking in front of an audience. Researchers can measure the total amount of cortisol released across a task, which reflects starting levels, as well as how much cortisol rises during the task. These two measures may capture different aspects of the body’s stress response.
Anxiety and externalizing problems, such as aggression, anger, or rule-breaking, often overlap in children and adolescents. Previous studies have found mixed links between cortisol and these symptoms, with some tying externalizing problems to heightened cortisol responses and others to blunted ones.
Led by Gretchen R. Perhamus of the Medical University of South Carolina, the research team examined whether a history of early trauma helped explain those varying patterns. Their predictions were guided by the adaptive calibration model, a theory proposing that the stress system adjusts to the level of threat in a child’s environment, so that the same stress response may relate to symptoms differently depending on a child’s experiences. They also considered whether cortisol was related to overall symptom levels or to which type of problem was more prominent.
The study included 189 youth ages 8 to 15 (average age about 11; 99 girls and 89 boys) from a larger community study in Charleston, South Carolina. Caregivers and youth were separately interviewed about a wide range of potentially traumatic experiences, including serious accidents, violence, abuse, neglect, separation from a caregiver, and natural disasters.
The researchers classified 107 participants as having experienced at least one such event before age 6, based on either the youth’s or the caregiver’s report, and 82 as having never experienced one at any age, based on both reports. Youth in the early trauma group came from households with lower average incomes and were less likely to be white.
During a laboratory visit, each young person gave a three-minute speech to a camera, as if auditioning for a TV show about kids their age, while a judge watched. The researchers collected saliva samples before and after the speech and during the following recovery period to measure cortisol, and usable cortisol data were available for 145 participants. The youth reported their own anxiety and externalizing symptoms at that visit and again two years later.
For youth with early trauma exposure, higher overall cortisol output during the task was linked with more externalizing symptoms at the same time, and with externalizing problems being more prominent than anxiety. Unexpectedly, higher overall cortisol output was linked with less anxiety in both groups.
Over the following two years, among youth with early trauma, a smaller cortisol increase during the task predicted a shift toward externalizing problems relative to anxiety, while a larger increase predicted a shift toward anxiety. Among youth with no trauma history, a larger cortisol increase predicted a decrease in anxiety over time.
The findings depended on which cortisol measure and symptom comparison the researchers examined. Overall cortisol output was linked to current symptoms, while the rise in cortisol was more informative about later changes in symptom patterns. Several associations among trauma-exposed youth emerged only when the researchers looked at which type of problem was more prominent, rather than at anxiety and externalizing symptoms separately.
The two groups did not differ in their cortisol responses. Among youth with early trauma, the number of early traumatic experiences did not change the links between cortisol and symptoms, although most of these youth had experienced only one or two such events.
Perhamus and colleagues summarized: “the specific pattern of findings was complex and depended on whether models examined concurrent or longitudinal associations, and whether they examined symptom domains or directionality.” In other words, the results did not point to one simple relationship between cortisol and mental health.
Some limitations should be noted. Trauma histories were reported retrospectively, and the researchers did not examine whether youth in the early-trauma group experienced additional traumatic events later in childhood or during the study. Because of the study design, the researchers could not test whether early trauma altered stress responses, which in turn shaped symptoms.
Puberty can also affect the stress system, and although the researchers accounted for pubertal development, it may still have influenced the results. The study measured cortisol without examining other parts of the body’s stress response, used broad measures of anxiety and externalizing problems, and drew on a relatively small community sample, so the authors say the findings need to be replicated.
The study, “Early trauma exposure moderates associations between cortisol reactivity and youth anxiety and externalizing symptoms,” was authored by Gretchen R. Perhamus, Rachel E. Siciliano, Tiffany Phu, Christopher T. Sege, Zachary W. Adams, Jane E. Joseph, Jason E. Chapman, Colleen A. Halliday, Colin Bowyer, Donte L. Bernard, Benjamin L. Hankin, Lisa M. McTeague and Carla Kmett Danielson.