stress and mental illness
August 2, 2014

The Role That Biological Methods And Pathways Play In Stress And Schizophrenia

Rayshell Clapper for - Your Universe Online

People suffer from stress under a litany of situations. Some situations are temporarily stressful and then dissipate while others lead to long-term psychological problems including post-traumatic stress disorder (PTSD). It seems that more people these days suffer from the consequences of stress, which leads to many studies about the mental illness.

In one study completed by Duke University, the study's senior author Dr. Kafui Dzirasa, assistant professor of psychiatry and behavioral sciences at Duke University Medical Center and Duke Institute for Brain Sciences member, noted that his team wanted to research possibilities of how to locate and control stress triggers in order to help not only with stress but also with other mental illnesses.

The research team found some exciting hope in their study. They analyzed two interconnected biological pathways in two brain areas that control fear and stress responses in mice that use the same areas as humans. These two focused brain areas were the prefrontal cortex (involved in planning and higher-level functions) and the amygdala (involved in the flight-fight-freeze functions). The prefrontal cortex suppresses the amygdala's reaction to danger in order to allow the mind and body to function in stressful situations.

The team implanted electrodes in the rodents' brains in order to listen to and analyze how the prefrontal cortex and the amygdala fired as well as to understand how they related to each other. This helped them to understand how the mice would respond in stressful situations. First, the researchers studied the firings in mice not under stressful situations in order to recognize just how the two brain areas worked together. Then, they put the mice in intentionally stressful situations such as daily exposure to an aggressive male mouse for about two weeks. At this point, researchers looked closely at the prefrontal cortex and amygdala of the stressed mice. They found that "the degree to which the prefrontal cortex seemed to control the amygdala activity was related to how well the animals coped with the stress."

Additionally, the team found that the initial stressful contact proved to harm mice more sensitive to stressful situations more, or at the very least the more sensitive mice showed that the interaction between the prefrontal cortex and the amygdala increased.

"We were really both surprised and excited to find that this signature was present in the animals before they were chronically stressed," Dzirasa said, further postulating that if researchers can pair the signatures with treatments, then perhaps they can prevent symptoms from emerging. This could even lead to greater understanding of other mental illnesses as Dzirasa indicated was one of the long-term goals.

One such mental illness that this research could benefit is schizophrenia, which has been studied but still leaves researchers with many questions. As reported in a recent article, scientists have discovered over 100 genetic risk factors to schizophrenia. They have also "revealed biological methods and pathways that may be linked to schizophrenia, and could lead to the first significant method of treating the disorder in more than six decades."

What Dzirasa and his team found about stress in relation to the prefrontal cortex and the amygdala is one such biological method that just might be able to help researchers and doctors who focus on schizophrenia.

Sir Michael Owen, Director of the Cardiff University School of Medicine MRC Centre for Neuropsychiatric Genetics and Genomics, said, "Detecting biological risk factors on this scale shows that schizophrenia can be tackled by the same approaches that have already transformed outcomes for people with other diseases." Both stress and schizophrenia have biological methods that may prove to help doctors teach those who suffer from them to control the illnesses, but these studies also bring hope to help prevent such mental illnesses as these.

For more on the Duke University study on stress, see the publication in the July 29, 2014, edition of Nature Communications. For more on the Cardiff University study on schizophrenia, see the journal Nature from earlier in July 2014.