August 15, 2012
Shrinking Of The Brain Linked To Depression And Stress
Connie K. Ho for redOrbit.com — Your Universe Online
Sad. Blue. Unhappy. Miserable. Down in the dumps. These are all different ways to describe depression. People can feel like this at least once in their life or in short periods. Since the exact cause of depression is unknown, scientists set out to better understand the factors that may play a role in depression like the chemical changes that take place in the brain. Researchers recently found that depression and chronic stress can block the creation of new nerve connections, causing the brain to shrink.
To begin, the research findings are particularly important as the shrinking of the brain can interrupt circuits related to emotional and mental functioning. The study could help explain why people who have major depressive disorder (MDD) have difficulty concentrating, suffer from memory loss, and display blunted emotional responses. Scientists also discovered that several genes associated with building synapses were limited in people who had MMD and could affect the shrinking of the brain´s prefrontal cortex. The findings are featured in a current edition of the journal Nature Medicine.
“We wanted to test the idea that stress causes a loss of brain synapses in humans,” commented study leader Professor Ronald Duman of the Yale School of Medicine commented in a Daily Mail article.” We show that circuits normally involved in emotion, as well as cognition, are disrupted when this single transcription factor is activated.”
In the project, scientists looked at brain tissue from patients who had passed away after diagnosis of MDD. They discovered molecular signs of reduced activity in genes that were needed for the function and structure of brain synapses. It may be due to a protein called GATA1, which also acts as a single genetic “switch” and transcription factor. According to Fox News, transcription factors can help manage which genetic instructions will be copied from the DNA when producing the body´s proteins. GATA1 can decrease the activity of genes and initiate a loss of brain connections.
Other studies with rats demonstrated that, when GATA1 was turned on, the animals´ demonstrated signs of depression. Researchers believe that loss of brain synapses could be connected to symptoms of depression and mental impairment. Symptoms of depression include irritability and agitation, fatigue and lack of energy, as well as feelings of hopelessness. Genetic variations in GATA1 could possibly help doctors identify people who are at risk for severing depression or sensitivity to stress.
“We hope that by enhancing synaptic connections, either with novel medications or behavioral therapy, we can develop more effective antidepressant therapies,” concluded Duman in the Daily Mail article.
Funding from the National Institutes of Health and Connecticut Department of Mental Health and Addiction Services supported the study.
According to the Huffington Post, in a previous study, Yale researchers also discovered that other stressful life moments could cause brain gray matter to shrink. These stressful moments may include getting a divorce, failing a class, or losing a job. Researchers plan to look into how brain matter is connected to emotional and physiologic functions as well as the impact it has on future psychiatric problems.