Early trauma may change what children’s cortisol responses reveal about mental health

A study of 189 young people suggests that different cortisol patterns after early trauma may be linked to shifting risks of anxiety and externalising behaviour, though the findings do not prove cause and effect.

Early trauma may shape how children’s bodies respond to stress, with different patterns of cortisol reactivity appearing to point towards different mental-health trajectories, according to research published in Development and Psychopathology and summarised by PsyPost.

The study focused on cortisol, a hormone released as part of the body’s stress response, and examined whether the size of that response during a social stress task was linked to anxiety and externalising problems such as aggression, anger or rule-breaking. Researchers led by Gretchen R. Perhamus at the Medical University of South Carolina looked at 189 children and adolescents aged 8 to 15 from a community sample in Charleston, South Carolina, and compared those who had experienced potentially traumatic events before the age of 6 with those who had not. The trauma group was more likely to come from lower-income households and less likely to be white, according to the report.

In the laboratory task, participants gave a brief speech to a camera while being observed, and saliva samples were collected before and after the speech and during recovery. Among young people with early trauma exposure, a larger overall cortisol output during the task was associated with more externalising symptoms at the same time and with externalising problems being more prominent than anxiety. By contrast, a higher cortisol increase during the task was linked over the following two years to a shift towards anxiety, while a smaller rise predicted movement towards externalising symptoms, according to the study summary and the PubMed abstract.

The findings add to earlier research suggesting that cortisol does not map neatly on to children’s emotional difficulties. One older study in early adolescence found that persistent anxiety was not tied to higher morning cortisol, but was linked instead to lower evening cortisol, while another review of previously institutionalised children and young adults argued that early adversity can alter stress reactivity in ways that may shape later emotional development. The new study’s authors said the pattern of results was complex and depended on whether they examined current symptoms or changes over time, as well as whether they looked at anxiety and externalising problems separately or in relation to one another.

Researchers also noted important limits. Trauma histories were reported retrospectively, the study could not prove that early trauma caused later changes in stress biology, and other aspects of the body’s stress system were not measured. Even so, the work suggests that the same cortisol response may carry different meaning depending on a child’s early experiences, underscoring the need for clinicians and researchers to look beyond one-size-fits-all models when assessing anxiety and behavioural difficulties.