Even in the healthy, stress causes brain to shrink, Yale study shows

The brain imaging study of more than 100 healthy subjects suggests these differences are apparent soon after stressful events occur and may serve as warning signals of future psychiatric disorders and chronic diseases, such as hypertension and diabetes, said Rajita Sinha, the Foundations Fund Professor of Psychiatry, and professor in the Department of Neurobiology and the Yale Child Study Center.

Chronic abuse, trauma, and stress have been linked to changes in brain structure and function in animals and to psychiatric disorders such as addiction, depression, and anxiety in humans. However, the effects of stress on brains of healthy individuals have been unclear. Yale researchers decided to look at the volume of gray matter - the tissue containing nerve cells and their branching projections called dendrites - in a group of community participants.

The highlighted area indicates a critical region of the brain, the prefrontal cortex, where gray matter volume decreased with every additional stressful life event an individual had experienced. This region is important for regulation of emotions, desires and impulses, and physiology.

The team conducted magnetic resonance imaging scans of 103 healthy subjects who had been interviewed about traumatic stress and adverse life events, such as the death of a loved one, loss of a home to natural disaster, job loss or divorce. They found that even the brains of subjects who had only recently experienced a stressful life event showed markedly lower gray matter in portions of the medial prefrontal cortex, an area of the brain that regulates not only emotions and self-control, but physiological functions such as blood pressure and glucose levels.

"The accumulation of stressful life events may make it more challenging for these individuals to deal with future stress, particularly if the next demanding event requires effortful control, emotion regulation, or integrated social processing to overcome it," said Emily Ansell, assistant professor of psychiatry and lead author of the study.

Sinha said that the study illustrates the need to address causes of stress in life "and find ways to deal with the emotional fallout."

"The brain is dynamic and plastic and things can improve - but only if stress is dealt with in a healthy manner," Sinha said. "If not, the effects of stress can have a negative impact on both our physical and mental health."

Other Yale-affiliated authors of the study are Kenneth Rando, Kerit Tuit, and Joseph Guarnaccia.

The study was funded by the National Institutes of Health