Research from the University of Cincinnati College of Medicine suggests a specific stress hormone pattern may signal vulnerability to post-traumatic stress disorder - at least in female animal models - and could help explain why women are diagnosed with PTSD at roughly twice the rate of men.
What did the UC PTSD study discover about stress hormones?
Researchers exposed both male and female animal models to a mild stressor and measured stress hormone levels in their blood. Researchers then exposed the animals to a more intense stress model to induce PTSD-like behavioral changes.
Weeks later, the animals underwent behavioral testing that measured anxiety, fear learning and fear extinction, or the ability to "unlearn" a fear response.
In females, those with a stronger hormonal reaction to the mild stressor were significantly more likely to develop PTSD-like deficits after the prolonged stressor, including increased anxiety, impaired fear extinction and enhanced reinstatement of fear. Specifically, low resting corticosterone combined with a higher stress-evoked spike predicted the worst outcomes - a measurable biological signature that may identify at-risk individuals before trauma occurs.
PTSD patients lose the ability to extinguish their fear.
James Herman, PhD Study's corresponding author, professor and co-chair of the Department of Biomedical Sciences
"PTSD patients lose the ability to extinguish their fear," said Herman, who is also director of UC's Neurobiology Research Center and associate director of UC's Gardner Neuroscience Institute . "They are too good at remembering factors associated with negative events."
In males, stress reactivity did not predict outcomes in the same way, confirming that stress hormone dynamics operate differently across sexes.
"This tells us that the way stress is processed is different in males and females," said Herman.
How could the findings help humans in the future?
The findings raise the possibility that a simple stress provocation test could one day serve as a clinical biomarker for PTSD risk and point toward early interventions.
"If we can identify people whose physiological stress response puts them at risk, we may be able to intervene earlier," Herman said. "There may be ways to block the stress response during the post-exposure period." He added that therapeutic approaches and future drug development could reduce the likelihood of developing lasting stress deficits after trauma.
Herman cautions that the research is preclinical and that the hormone pattern is a candidate biomarker, not a diagnostic test. Next, the team must determine whether similar patterns appear in women who have experienced trauma and whether they predict who goes on to develop PTSD.
"We want to understand what is happening in the brains of susceptible females that distinguishes them from resilient females and from males," he said. "Can we use that knowledge of their brain circuitry to develop better treatments?"
Research collaborators include Devine, a neuroscience graduate student in Herman's lab, along with others from UC: James B. Chambers, Taylorae Dunn, Ava Musarra, Sophie Porter, Christine E. Moore, Marissa Smail, Nawshaba Nawreen and Ben A. Packard.
The U.S. Department of Veterans Affairs partially funded the study.
Featured image at the top: UC neuroscientist James Herman, PhD, and colleagues report that a specific pattern of stress hormones in female animal models may signal vulnerability to PTSD, offering a potential biomarker that could help explain why women are diagnosed at roughly twice the rate of men. Photo/iStock/martin-dm.
Frequently asked questions about UC's PTSD biomarker research:
What biomarker did UC researchers identify for PTSD risk? right arrow down arrow
In female animal models, the team found a specific stress hormone pattern associated with PTSD-like behavior, suggesting it may be a biomarker of PTSD susceptibility.
Why focus on females in this study? right arrow down arrow
Women are diagnosed with PTSD at roughly twice the rate of men, and the researchers wanted to explore whether sex-specific differences in stress physiology help explain the increased vulnerability.
Does this mean there is a blood test for PTSD? right arrow down arrow
Not yet. The findings are from animal models, and more research is needed to see whether similar hormone patterns in humans could help predict PTSD risk or guide prevention.
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