Gerald Hurowitz, M.D.·Published 8 March 2012·7 min read
Key points
Anyone who has ever been subject to chronic stress knows that it can take a toll on emotions and the ability to think clearly.
Stress has mental, emotional and physical components.
Stress is often described as a feeling of being overwhelmed, worried or run-down.
The memory loss from stress is not the same as memory loss from a physical head injury.
Anyone who has ever been subject to chronic stress knows that it can take a toll on emotions and the ability to think clearly. Now, new research uncovers a neural mechanism that directly links repeated stress with impaired memory. The study, published by Cell Press in the March 8 issue of the journal Neuron, also provides critical insight into why stress responses can act as a trigger for many mental illnesses.
Stress hormones are known to influence the prefrontal cortex (PFC), a brain region that controls high level "executive" functions such as working memory and decision making. "Previous work has shown that chronic stress impairs PFC-mediated behaviors, like mental flexibility and attention. However, little is known about the physiological consequences and molecular targets of long-term stress in PFC, especially during the adolescent period when the brain is more sensitive to stressors," explains the author this study, Dr. Zhen Yan, from the State University of New York at Buffalo. "
Dr. Yan and colleagues examined whether repeated stress had a negative influence on glutamate receptors in juvenile rats. Glutamate signaling plays a critical role in PFC function. They found that in response to repeated stress, there was a significant loss of glutamate receptors, which resulted in a deficit of PFC-mediated cognitive processes. The researchers went on to identify the molecular mechanisms that linked stress with the decrease in glutamate receptors and demonstrated that if they blocked these mechanisms, the stress-induced decrease in both glutamate receptors and recognition memory could be prevented.
Taken together, the findings identify a loss of glutamate receptors as an important target of repeated stress and link chronic stress with abnormal PFC function. "Since PFC dysfunction has been implicated in various stress-related mental disorders, delineating molecular mechanisms by which stress affects the PFC should be critical for understanding the role of stress in influencing the disease process," concludes Dr. Yan.
High Stress Hormone Levels Impair Memory St. Louis, June 15, 1999 - If it's been a really, really tough week at work and you can't remember where you put your car keys, it may be that high levels of the stress hormone cortisol are interfering with your memory. In the June Archives of General Psychiatry, investigators at Washington University School of Medicine in St. Louis provide the first direct evidence that several days of exposure to cortisol at levels associated with major physical or psychological stresses can have a signifcant negative effect on memory.
"We tested memory and other cognitive functions before treatment, after one day of treatment and again after four days, in individuals receiving either a high dose of cortisol, a lower dose or an inactive substance," explained lead author John W. Newcomer, M.D., assistant professor of psychiatry and psychology. "We saw memory impairment only in the individuals treated with the higher dose and only after four days of exposure. The good news is it appears that it would take several days of stresses like major surgery or severe psychological trauma in order for cortisol to produce memory impairment. And after a one-week wash-out period, memory performance returned to the untreated levels."
Written and revised by
Gerald Hurowitz, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
health.am provides general information, not medical advice. Always consult a qualified health professional about your own health.
Cortisol is produced in the body during stress. It belongs to a family of stress hormones called glucocorticoids that, among other actions, can interfere with energy supply to certain brain cells involved in memory. Newcomer's previous work showed that treatments with a synthetic glucocorticoid called dexamethasone impaired memory. But this is the first study to demonstrate that prolonged exposure to high levels of cortisol-the hormone actually produced in the body in response to high stress- has that same negative effect.
Studies have illustrated the strong link between insomnia and chronic stress and, according to APA’s 2010 Stress in America survey, more than 40 percent of all adults say they lie awake at night because of stress. Experts recommend going to bed at a regular time each night, striving for at least seven to eight hours of sleep and eliminating distractions such as television and computers from the bedroom.
Stress Insomnia
Stress has mental, emotional and physical components. Insomnia is mostly a result of mental tension.
As stress becomes prolonged, the ability to focus becomes a limitation instead. The mind is unable to let go. The conscious mind doesn't see a clear solution for a problematic situation, and basically dumps it on the subconscious, which tries to solve it through brute force.
Constant stress lowers the level of consciousness and affixes it there. If we can raise the level of consciousness, we can look from other perspectives, solve the problem and hopefully release the stress. Insomnia occurs when we don't let it go lower either, in which case we disrupt a natural cycle, rob the body of natural rest and try to force inadequate solutions on the subconscious.
To heal stress related insomnia, there is only one choice: to completely let go of the stressful situation and accept the consequences. By doing so we allow the subconscious to do its recuperative magic, and provide the conscious mind with much needed deep rest.
{pagebreak}
Understanding chronic stress
Stress is often described as a feeling of being overwhelmed, worried or run-down. Stress can affect people of all ages, genders and circumstances and can lead to both physical and psychological health issues. By definition, stress is any uncomfortable "emotional experience accompanied by predictable biochemical, physiological and behavioral changes." Some stress can be beneficial at times, producing a boost that provides the drive and energy to help people get through situations like exams or work deadlines. However, an extreme amount of stress can have health consequences and adversely affect the immune, cardiovascular, neuroendocrine and central nervous systems.
In addition, an extreme amount of stress can take a severe emotional toll. While people can overcome minor episodes of stress by tapping into their body’s natural defenses to adapt to changing situations, excessive chronic stress, which is constant and persists over an extended period of time, can be psychologically and physically debilitating.
Unlike everyday stressors, which can be managed with healthy stress management behaviors, untreated chronic stress can result in serious health conditions including anxiety, insomnia, muscle pain, high blood pressure and a weakened immune system. Research shows that stress can contribute to the development of major illnesses, such as heart disease, depression and obesity. According to a 2010 survey by the American Psychological Association (APA), health care providers are more likely to advise adults to reduce their stress levels when they consider their health as fair or poor than if they rate their health as excellent or good. Some studies have even suggested that unhealthy chronic stress management, such as over-consuming "comfort" foods, has contributed to the growing obesity epidemic. The APA survey also found that obese adults were more than twice as likely as normal-weight adults to have been told by a health professional to reduce their stress levels.
The consequences of chronic stress are serious, particularly as it contributes to anxiety and depression. People who suffer from depression and anxiety are at a heightened risk for heart disease, with depression leading to a two-fold increased risk and anxiety a doubling of increased risk. Additionally, people exposed to chronic stress are at a heightened risk of developing drug addiction.
Stress Memory Loss
The memory loss from stress is not the same as memory loss from a physical head injury.
Stress related memory has to do more with perception. Prolonged stress tends to 'flatten' the perceptive process, you notice only things related to the stressful situation that occupies your mind. The conscious mind tells the subconscious mind "These are the important things," and the subconscious mind does it's best to provide only relevant information and withhold the rest.
It's not that memory loss causes things to be forgotten, but that they are deemed to be not important. When the same stressful state of mind is repeated day after day, the mind becomes conditioned to react to the pressures in specific ways, and that includes selective remembering.
The danger from stress is not simply memory loss, but the fact that the way you think about yourself, your loved ones and the world changes negatively.
Stress Fatigue
Fatigue is the first and most common symptom of stress, and it is also the most curable.
Fatigue is a direct outcome of stress. The mind shifts into a higher gear and consumes more energy, and the body assumes there is a physical threat and goes into a tense state of readiness. When this state is prolonged, the body starts burning the reserves and damaging the 'infrastructure'.
Rest very efficiently cures fatigue. With the conscious mind out of the way, the body is able to restore itself quickly and fully. However, the conscious mind also has to learn to overcome its problems, because the body can go through only so many cycles of high damage and high healing before making a mistake somewhere.
For long term, deep, and healing rest confusion and conflict of the conscious mind have to be let go. Take a five minute rest, get a good night's sleep, take a vacation - or change your daily routine if necessary.
###
Yuen et al.: "Repeated Stress Causes Cognitive Impairment by Suppressing Glutamate Receptor Expression and Function in Prefrontal Cortex."
###
Elisabeth (Lisa) Lyons elyons@cell.com 617-386-2121 Cell Press
Acute psychological stress reduces ability to withstand physical pain
Traffic slows to a crawl, then a stop. You are trapped in a bottleneck nightmare, and late for a meeting. The stress takes a toll on you psychologically - but your body is at risk as well, according to a Tel Aviv…
