Stress is an integral part of all of our lives, so much so, in fact, that we tend to shrug off our racing pulses and insomnia and constant angst as nothing unusual. But researchers say that even everyday stress can be leading to changes in the brain that make us more vulnerable to mental as well as social disorders ranging from depression to addiction and behavioral conditions.
Dr. Rajita Sinha, a professor of psychiatry and neurobiology at Yale University School of Medicine and director of the Yale Stress Center, reports in the journal Biological Psychiatry that even among healthy individuals, adverse life events that cause stress can lead to shrinkage in parts of the brain responsible for regulating emotions and metabolism. In addition, she and her team found that it’s not individual traumatic events that have the most impact, but the cumulative effect of a lifetime’s worth of stress that might cause the most dramatic changes in brain volume.
Sinha imaged the brains of 100 healthy participants who had provided information on traumatic and stressful events in their lives, including divorce, death of a loved one, loss of a home or loss of a job. Even very recently affect subjects showed smaller grey matter in their brains in the prefrontal cortex, a region that is responsible for self-control, emotions and physiological functions such as maintaining proper glucose and insulin levels.
“The key take home message is that across the board the area that is most vulnerable to stress of any kind is the prefrontal cortex,” says Sinha. “It’s important for top-down regulation of our emotions, cognition, desires, and impulse control.” As nerve tissue in this region disappears due to constant battering from repeated stressful events, our ability to counteract potentially dangerous desires, such as for addictive substances, or control our impulsive behaviors to do dangerous things, may wane. “The prefrontal cortex is important for metabolic homeostasis and for our survival and adaptation to life’s challenges,” says Sinha.
Interestingly, by analyzing the brain scans, Sinha and her team were also able to distinguish how different types of stress affect different regions of the brain. Recent life events, such as a traumatic accident, a job loss or a difficult medical diagnosis seem to predominantly affect our emotional awareness. As this part of the brain shrinks, we may start to lose touch with our emotions, and act in inappropriate or even unfeeling ways to both situations as well as in our interactions with other people.
Life traumas, such as living with a chronic condition such as cancer or losing a loved one, seems to affect our mood centers most acutely, skewing our ability to regulate pleasure and reward. Smaller brain volumes in these centers have been linked to depression and other mood disorders such as anxiety.
Finally, chronic stress, the kind that we seem to all live with day in and day out — making deadlines at work, and juggling work and family life — doesn’t seem to affect brain volumes on its own. But, says Sinha, people experiencing chronic stress may be more vulnerable to suffering from brain shrinkages in key areas when they are faced with a life trauma or sudden adverse event. That’s because chronic stress may erode parts of the brain gradually, just enough so it’s not perceptible but, enough that when a truly stressful event occurs, its effects are magnified and our ability to cope is compromised “Over time, as the number of cumulative stressors increases, chronic stress can interact with that and worsen the effect,” says Sinha.
That’s important since understanding that stresses can build up may help more people to address the adversity in their lives and steer their brains away from its negative effects. “The brain is plastic, and there are ways to bring back and perhaps reverse some of the effects of stress and rescue the brain somewhat,” she says. Relieving stress through exercise or meditation is an important way to diffuse some of the potentially harmful effects it can have on the brain. Maintaining strong social and emotional relationships can also help, to provide perspective on events of experiences that may be too overwhelming to handle on your own.