mental health

Long-Term Discrimination Messes With the Body's Ability to Manage Stress

A new study shows how internalised pain is inhibiting the release of stress-relieving cortisol in Indigenous Australians.

by Katherine Gillespie
07 February 2017, 1:59am

According to new research from James Cook University, young Indigenous Australians may experience greater mental health difficulties after their biological stress responses are recalibrated by long-term discrimination. Scientists found that the stress hormone cortisol was functioning inefficiently within the young Indigenous participants in their study—many of whom had internalised harmful ethnic stereotypes.

To examine the variation between biological stress responses of Indigenous and non-Indigenous university students, the James Cook researchers subjected both groups to laboratory-induced stresses, then swabbed their tongues to measure their levels of cortisol.

In healthy adults, daily stresses and struggles are kept in check by a daily "awakening" release of cortisol, released into the body every morning. A safe level of cortisol concentration within the bloodstream helps keep stress at bay and contributes to good mental health. Too little or too much cortisol can lead to significant mental health issues.

Both groups of participants had reported similar stress and depression levels prior to commencing the study, but the researchers found that the bodies of Indigenous students were failing to release adequate levels of cortisol to cope with the artificial "stressful" environment. Those participants whose biological response to stress was inhibited were also those who reported feelings of internalised racism. 

"Self-reported racial discrimination was strongly associated with flattened cortisol response to stress," the study reads.

According to the study, it's highly unlikely that the observed abnormalities in cortisol functioning within Indigenous participants are due to genetic factors, since the non-Indigenous control group of participants was comprised of an "ethnically diverse group of individuals." A direct relationship between racial discrimination and poorly functioning biological stress mechanisms was much more likely.

It was also proposed by the study that transgenerational traumas experienced by Indigenous people might have inhibited the functioning of their stress relief mechanisms. "We cannot rule out that cumulative stressful experiences between childhood and adulthood that were not covered by our instruments or exposure to traumatic events in previous generations," it reads.

We already know that Australia's Indigenous people, and particularly young Indigenous people, are at a much more severe mental health risk than their non-Indigenous peers. So the research gives us a biological angle on the mental health gap. Indeed, lead author Professor Zoltan Sarnyai was optimistic about the potential of these findings to give our approach to Indigenous mental health issues a more biological bent.

"It may allow us in the future to objectively monitor efficacy of programs and policies to reduce the Indigenous health gap," he said in a statement released alongside the study.

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