Certain markers in the brain can predict an individual’s risk of developing depression and anxiety, Duke researchers have found.
The study conducted by Duke researchers concludes that the brain’s amygdala—an area associated with memory, emotions and decision-making—plays a major role in depression. High amygdala reactivity in response to high levels of stress can be indicative of a person’s vulnerability to developing depression and other mental illnesses, according to the recent article authored by Duke scientists in the journal "Neuron."
“We were able to predict several years out,” said Johnna Swartz, lead author of the study and post-doctorate associate in Hariri lab in the psychology and neuroscience department. “That was surprising because nobody had looked at if brain function could predict someone’s psychological vulnerability to depression, and if so, how far out in time brain function could predict.”
Swartz’s research is part of the lab's Neurogenetics study started by senior author Ahmad Hariri, professor in Psychology & Neuroscience, and aims to find genetic and brain markers associated with various mental illnesses.
The study found that individual amygdala responses to stress did predict a person’s higher risk of depression, even four years in the future.
Previous studies have concluded that the amygdala is a predictive biomarker for post-traumatic stress disorder in soldiers who were deployed in war-zone combat. Swartz' research, however, was the first study to demonstrate amygdala’s role in more common stressful life events.
“Rather than severe trauma, we wanted to look at the life events that a lot of people deal with,” Swartz said.
The 753 participants of the study—all Duke undergraduates aged 18 and 22 years old—had to provide genetic data and do an functional Magnetic Resonance Imaging scan, where they were shown faces with fearful or angry expressions. This measured the amygdala’s response to potentially threatening faces and stress, Swartz explained.
One year later, the participants were asked to fill out an online questionnaire that included a checklist of common life events that they might have experienced and questions about what impact these events had on them.
“Going through a breakup, failing a class, losing a job—those are the types of things that were on the questionnaire and that students experience,” Swartz said.
The follow-ups, which were sent out for several years, determined if an individual was exhibiting symptoms of depression and whether those symptoms correlated with stressful events.
“We found that high amygdala response and high stress led to high levels of anxiety,” she explained. “There had to be a combination of both.”
Because amygdala reactivity indicates someone’s inherent risk of developing depression or anxiety, a major implication of this study is an increased ability to predict and treat these disorders.
Due to the high expenses of the fMRI scan, Swartz' team is working on identifying gene markers for amygdala function—a much easier and cheaper tool for analytics.
"[Gene markers] would also predict for depression risk,” Swartz explained. “By screening people, we can guide those at risk to seek treatment earlier on, rather than waiting for the problem to get really severe and chronic before they enter treatment.”
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