In a new study from Emory University, researchers found a novel biomarker indicating resilience to chronic stress.
But this biomarker is largely absent in people suffering from major depressive disorder, and this absence is further linked to pessimism in daily life.
Around 16% to 20% of the U.S. population will meet the criteria for a major depressive disorder during their lifetimes. Experts are predicting rates of depression to climb even further in the wake of the ongoing COVID-19 pandemic.
It’s long been known that stress is a major risk factor for depression, one of the most common and debilitating mental illnesses. In many ways, depression is a stress-linked disorder.
It’s estimated that 80% of first-time depressive episodes are preceded by significant, chronic life stress.
Although the link between stress and depression is clearly established, the mechanisms underlying this relationship are not.
In the study, the team used brain imaging to identify differences in the neurotransmitter glutamate within the medial prefrontal cortex before and after 88 participants underwent stressful tasks.
They then followed the participants for four weeks, using a survey protocol to regularly assess how participants rated their expected and experienced outcomes for daily activities.
They found that glutamate in the human medial prefrontal cortex shows adaptive habituation to a new stressful experience if someone has recently experienced a lot of stress.
Importantly, this habituation is strongly altered in patients with depression.
The researchers believe this may be one of the first biological signals of its kind to be identified in relation to stress and people who are clinically depressed.
They say the decrease in the glutamate response over time appears to be a signal, or a marker, of a healthy adaptation to stress.
And if the levels remain high that appears to be a signal for maladaptive responses to stress. It may predict an increased pessimistic outlook—a hallmark for depression.
If you care about depression and your health, please read studies about 9 high blood pressure drugs could lower depression risk and findings of this supplement may reduce depression.
For more information about depression and mental health, please see recent studies about anxiety, depression should not be taken as mental diseases and results showing that using these drugs to treat depression may cause higher death risk.
The study is published in Nature Communications. One author of the study is Michael Treadway.
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