Category: Stress

 Bad news articles in the media increase women's sensitivity to stressful situations, but do not have a similar effect on men, according to a study undertaken by University of Montreal researchers at the Centre for Studies on Human Stress of Louis-H. Lafontaine Hospital. The findings were published October 10 in PLOS One. The women who participated in the study also had a clearer recollection of the information they had learned. "It's difficult to avoid the news, considering the multitude of news sources out there, said lead author Marie-France Marin. "And what if all that news was bad for us? It certainly looks like that could be the case."

The researchers asked 60 people divided into four groups to read actual news stories. In order to determine their stress levels, the researchers took samples of the participants' saliva and analyzed them for a hormone called cortisol. Higher levels of this bodily chemical indicate higher levels of stress. A group of men and a group of women read "neutral" news stories, about subjects such as the opening of a new park or the premiere of a new film, while the another two gender segregated groups read negative stories, about events such as murders or accidents. Saliva samples were taken again in order to determine the effect of these news stories. "When our brain perceives a threatening situation, our bodies begin to produce stress hormones that enter the brain and may modulate memories of stressful or negative events," explained Sonia Lupien, Director of the Centre for Studies on Human Stress and a professor at the university's Department of Psychiatry. "This led us to believe that reading a negative news story should provoke the reader's stress reaction."

The participants were then confronted with a series of standardized tasks involving memory and intellect that enable researchers to evaluate and compare how people react to stressful situations. A final round of samples was then taken to determine the effects of this experience. Finally, the next day, the participants were called back to talk about what they had read. The researchers were surprised by what they found. "Although the news stories alone did not increase stress levels, they did make the women more reactive, affecting their physiological responses to later stressful situations," Marin explained. The researchers discovered this when they saw that the level of cortisol in the women who have read the negative news was higher after the "stress" part of the experiment compared to the women who have read the neutral news. "Moreover, the women were able to remember more of the details of the negative stories. It is interesting to note that we did not observe this phenomenon amongst the male participants."

The researchers believe that evolutionary factors may be at play, noting that other scientists have considered whether an emphasis on the survival of offspring may have influenced the evolution of the female stress system, leading women to be more empathetic. This theory would explain why women could be more susceptible to indirect threats. "More studies should be undertaken to better understand how gender, generational differences and other socio-cultural factors affect our experience, as individuals, of the negative information that perpetually surrounds us," Marin said.

— Could the impact of chronic stress explain why American black girls are more likely to be overweight than white girls? According to Dr. Tomiyama of the University of California, Los Angeles in the U.S., and her colleagues, higher levels of stress over 10 years predict greater increases in body weight over time in both black and white girls. However, the experience of chronic stress appears to have a greater negative effect on black girls' weight, which may explain racial disparities in obesity levels.

The work is published online in Springer's journal, Annals of Behavioral Medicine.

In the United States, the prevalence of obesity in black populations is 50 percent higher than in whites. This difference is apparent even in childhood, and particularly in female adolescents. In addition, ethnic minorities tend to experience greater psychological stress than whites due, in part, to perceived racial discrimination.

Tomiyama and team looked at whether the experience of chronic stress in young girls over a 10-year period might have an effect on Body Mass Index (BMI), a measure of obesity. They were also interested in whether this effect might be different in white and black teenage girls.

Using data from the National Heart, Lung and Blood Institute's (NHLBI) Growth and Health Study, the researchers assessed the prevalence of obesity in 2,379 black and white girls beginning at age 10 and followed up for 10 years. They also looked at their experience of psychological stress over that time.

Over 10 years, more black girls were overweight or obese than white girls, who reported more stress than black girls. In addition, levels of chronic stress predicted greater weight in both groups. Even though black girls reported less stress overall, the effect of chronic stress on weight was stronger for these girls with one unit increase in stress leading to 0.8 BMI unit increase every two years. Comparatively, one unit of stress led to 0.55 BMI unit increase in white girls.

The authors conclude: "Our study documents a relationship between chronic perceived stress and BMI over a decade of growth in black and white girls. However, the relationship between perceived stress and BMI is stronger in black girls. Psychological stress may lead to weight gain through behavioral pathways, such as increased food consumption and sedentary lifestyles, but also directly through prolonged exposure to biological stress mediators such as cortisol."

Given how ubiquitous stress is, these findings raise the flag that stress may be playing a major role in the obesity epidemic as well as contributing to racial disparities.

— A new study on the physiological effects of stress has found that expectant parents respond differently to arguments depending on the presence of ongoing individual or relationship difficulties such as anxiety or chronic relationship conflict.

The study by Mark Feinberg and Damon Jones from Pennsylvania State University published online in the British Journal of Psychology on October 12, examined whether anxiety or chronic relationship difficulties altered the way that a 12-minute couple conflict discussion affected partners' cortisol levels.*

Mark Feinberg said: "Relationship conflict has been shown to have a major impact on partners' mental health and well being. It's especially important to understand how relationship conflict may affect stress during pregnancy as maternal stress has previously been linked to health problems for both the mother and child. And men who have difficulty dealing with stress could end up reacting angrily to future disagreements, affecting the quality of the relationship, parent-child relations, and children's adjustment."

As expected, greater hostility in a conflict discussion led to increased levels of cortisol, indicating greater physiological stress, for men. However, the same relation was not found for women — which may be due to the fact that pregnant women's cortisol levels are already high.

One hundred and thirty eight heterosexual couples expecting their first child (82 per cent were married) took part in the study. In their own home, expectant parents separately completed questionnaires regarding their relationship experiences and individual qualities, attitudes, and well-being. Interviewers videotaped two 6-minute interactions of each couple discussing something not related to their relationship. Next the couples were asked to discuss three problems in their relationship (such as money and housework).

During the home interview, three cortisol samples were taken (from saliva). A baseline sample was taken first before the videotaped interactions, the second was taken after the conflict discussion to examine reactivity-that is, whether cortisol levels increased due to the conflict discussion. The third sample was taken 20 minutes after the second sample to assess whether levels of cortisol had gone back down as they typically do after a brief stressor, indicating recovery from the stress of the conflict.

One finding established how anxious men and women reacted differently to arguing: hostility during the conflict discussion led to less cortisol recovery for men, but more cortisol recovery for women. The same pattern was found for men and women who reported high levels of chronic, unresolved relationship conflict.

Mark Feinberg explained: "We found that generally anxious men appeared to find hostility stressful and this elevated stress persisted for a longer period of time. On the other hand, generally anxious women experienced relatively more prolonged stress when there were lower levels of negativity and hostility expressed during the discussion. We speculate that these anxious women, as well as women in relationships of chronic arguing, find the airing of differences, even when the tone turns negative, to be reassuring that the couple is engaged with each other. This may be particular important for women during the vulnerable period of first pregnancy."

Mark Feinberg added: "It would be useful for couples to understand that they need to carefully balance the apparently beneficial effects of discussing difficult relationship topics for some women with the apparently negative effect for some men."

*Cortisol is a hormone released in response to stress and high levels of cortisol may have long-term negative effects on health.

Wayne State University School of Medicine researchers may have discovered why people exposed to war are at increased risk to develop chronic problems like heart disease years later. And the culprit that links the two is surprising.

Beginning in the mid-2000s, WSU researchers interviewed a random sample of 145 American immigrants who left Iraq before the 1991 Gulf War, and 205 who fled Iraq after the Gulf War began. All were residing in metropolitan Detroit at the time of the study. Study subjects were asked about socio-demographics, pre-migration trauma, how they rated their current health, physician-diagnosed and physician-treated obstructive sleep apnea, somatic disorders and psychosomatic disorders. Those who left Iraq after the war began and suffered from mental disorders such as post-traumatic stress disorder (PTSD) and depression, and self-rated their physical health as worse than their actual health, were 43 times more likely than pre-Gulf War immigrants to report obstructive sleep apnea (30.2 percent versus 0.7 percent) and later develop major chronic health issues such as cardiovascular disease.

"I was surprised, but we had a specific theory we wanted to test. Changes in the stress system would contribute to sleep apnea. What happens? Maybe it's the stress that leads to this fractured sleep," said Bengt Arnetz, M.D., Ph.D., M.P.H., School of Medicine professor of occupational and environmental health, deputy director of the Institute of Environmental Health Sciences at Wayne State, and the study's principal investigator and first author. "No one had explored this possible link before, although basic research suggests it as plausible."

The results are featured in the October 2012 issue of Psychosomatic Medicine, the peer-reviewed journal of the American Psychosomatic Society.

According to the article, "Obstructive Sleep Apnea, Post-traumatic Stress Disorder, and Health in Immigrants," obstructive sleep apnea occurs when the muscles supporting the soft palate at the back of the throat relax, but less is known about the reasons behind this neuromuscular malfunctioning.

"It's a known fact that the more exposure to violence you have, the more likely you are to report PTSD and depression, and the worse your self-rated health is, the more likely your actual health will suffer in five to 10 years," Arnetz said.

Hikmet Jamil, M.D., Ph.D., professor of occupational and environmental health in WSU's School of Medicine, and Thomas Templin, Ph.D., research professor in WSU's College of Nursing, also contributed to the article.

The obstructive sleep apnea and chronic disase link has been observed among many trauma-exposed populations, including refugees, Arnetz said.

"Iraqis were exposed to harsh conditions during the entirety of Saddam Hussein's more than 20 years of reign. However, trauma and environmental exposures increased measurably and dramatically after the initiation of the 1991 Gulf War," the article states.

The study can now be used as a model for other populations, including U.S. soldiers returning home from battle.

The multidisciplinary study brought together mental health research, sleep research and chronic disease research, Arnetz said.

He and Jamil were partially supported by the National Institute of Mental Health of the National Institutes of Health (award number R01MH085793).

To further test their ideas, the researchers plan to apply for funding from the National Institutes of Health to collaborate with Safwan Badr, M.D., professor and chief of the School of Medicine's Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, and Thomas Roth, Ph.D., director of the Henry Ford Sleep Disorders and Research Center.

Men and women who are expectant parents have different stress reactions to relationship conflict, according to researchers at Penn State, who studied couples expecting their first child. In addition, recovery from the initial reaction to conflict also can be different for men and women, depending on individual difficulties, such as anxiety, or relationship difficulties, such as chronic relationship conflict.

The researchers found that men's increased stress levels — measured by the amount of the stress hormone cortisol — during a conflict discussion depended on the level of hostility the couple expressed. More hostility led to a larger stress reaction for men, but the stress levels of pregnant women during the discussion were not linked to the amount of hostility expressed.

The team also found that recovery from the conflict discussion — measured by assessing cortisol levels 20 minutes later — did not differ for men and women with low levels of anxiety. However, men with a high level of anxiety recovered less, whereas women with high anxiety recovered more if the couple had expressed a high level of hostility during the discussion. The same pattern was found for men and women who reported low versus high levels of chronic, unresolved relationship conflict.

"Hostility and negativity in a relationship has been shown to have a major impact on mental health and the future well being of the couple," said Mark Feinberg, research professor in the Prevention Research Center for the Promotion of Human Development at Penn State. "It is especially important to understand how relationship conflict may affect stress during pregnancy, as maternal stress has been linked to health problems for both the mother and child. And men who have difficulty dealing with stress could end up reacting angrily to future disagreements, which could affect the quality of the relationship, parent-child relations and children's adjustment."

The researchers recruited 138 heterosexual couples expecting their first child (82 percent were married) to participate in the study. In their own homes, the expectant parents separately completed questionnaires regarding their relationship experiences and individual qualities, attitudes and well-being. Interviewers videotaped two six-minute interactions of each couple discussing something not related to the relationship. Next, the couples were asked to discuss three problems in their relationship, such as money and housework.

During the home interviews, the researchers collected three saliva samples from each of the participants in order to measure the amount of cortisol contained within the saliva. They collected the first baseline sample prior to videotaping the interactions among the participants. They collected the second sample after the conflict discussion to examine the participants' reactivity to the conflict. They collected the third sample 20 minutes after the second sample to assess whether cortisol levels had gone back down as they typically due after a brief stressor, indicating recovery from the stress of the conflict.

As expected, the researchers found that greater hostility in a conflict discussion led to increased levels of cortisol, indicating greater physiological stress, for men. The same pattern was not found for women. However, the researchers noted this may be due to the fact that women's cortisol levels are already high during pregnancy.

In examining the participants' recovery to conflict, men with a high level of anxiety recovered less, whereas women with high anxiety recovered more. The same pattern was found for men and women who reported low versus high levels of chronic, unresolved relationship conflict.

The research findings appeared in the British Journal of Psychology at the end of the week of October 15.

"We found that all men appeared to find hostility stressful," said Feinberg. "For generally anxious men, more expressed hostility was also linked to more persistence of this elevated stress. On the other hand, generally anxious women experienced relatively more prolonged stress when there were lower levels of negativity and hostility expressed during the discussion. We speculate that these anxious women, as well as women in relationships in which chronic arguing is a feature, find the airing of differences, even when the tone turns negative, to be reassuring that the couple is engaged with each other. This may be particularly important for women during the vulnerable period of their first pregnancy. It would be useful for couples to understand that they need to carefully balance the apparently beneficial effects that discussing difficult relationship topics had for some women with the apparently negative effects it has on some men."

The National Institutes of Health provided funding for this research. Damon Jones, research assistant professor in the Prevention Research Center for the Promotion of Human Development at Penn State, and Doug Granger, professor at Johns Hopkins University, also were involved with the work.

— Researchers report new insights into how the brain responds to extreme stress, whether from combat, natural disasters, or repeated violent competition.

The insights offer hope for detecting and treating several widespread and debilitating neuropsychiatric disorders, and were presented at Neuroscience 2012, the annual meeting of the Society for Neuroscience and the world's largest source of emerging news about brain science and health.

Post-traumatic stress disorder (PTSD) is a severe anxiety disorder that can develop after experience of a traumatic or terrifying event, such as those experienced in combat or from sexual aggression. Such events can overwhelm the individual's ability to cope and lead to a long-lasting disorder. Symptoms include re-experiencing the original trauma through flashbacks or nightmares, often triggered by seemingly innocuous events. PTSD can harm an individual's relationships, ability to work, to sleep, and other aspects of life.

The lifetime prevalence of PTSD among adult Americans is 8 percent. Neither drug nor behavioral treatments currently available are consistently effective in treating PTSD. Therefore, scientists are studying brain changes associated with PTSD and related cognitive disorders, looking for clues to help in the development of new treatments.

Today's findings show that:

• A fast-acting antidepressant, ketamine, appears to aid the formation of new nerve connections in the brain, helping to extinguish fearful memories. The mouse study could possibly lead to new PTSD treatments (Neil Fournier, PhD, abstract 399.09).
• In a mouse model, when dopamine neurons in the brain's reward system are turned on and off with a genetically engineered "light switch," depressive symptoms also come and go. The research highlights the importance of this neural circuit as a potential target for new depression treatments (Dipesh Chaudhury, PhD, abstract 522.01).
• Brain images of adolescents taken before and after the 2011 Japanese earthquake reveal that pre-existing weakness in certain brain connections could be a risk factor for intensified anxiety and PTSD after a traumatic life experience (Atsushi Sekiguchi, MD, PhD, abstract 168.12).
• Rodent studies show that repeated violent, competitive encounters drive changes in brain activity that shapes the ongoing behavior of losers and winners in distinct ways, and can contribute to depression and/or anxiety (Tamara Franklin, PhD, abstract 399.10).

Other recent findings discussed show:

• How exposure to stress causes molecular changes that weaken the ability of the prefrontal cortex to regulate behavior, thought, and emotion, while strengthening more primitive brain circuits (Amy Arnsten, PhD, abstract 310).

"New methods for looking deep into the brain are revealing a dynamic landscape that changes as it must to cope with trauma," said press conference moderator Sheena Josselyn, PhD, from the Hospital for Sick Children in Toronto, Ontario, an expert on the neural basis of brain function. "The more we learn about those changes, and how experiences remodel the brain, the more tools we will acquire for treating disorders that affect millions of people."

This research was supported by national funding agencies such as the National Institutes of Health, as well as private and philanthropic organizations.

A new study in animals shows that chronic stress during pregnancy prevents brain benefits of motherhood, a finding that researchers suggest could increase understanding of postpartum depression.

Rat mothers showed an increase in brain cell connections in regions associated with learning, memory and mood. In contrast, the brains of mother rats that were stressed twice a day throughout pregnancy did not show this increase.

The researchers were specifically interested in dendritic spines — hair-like growths on brain cells that are used to exchange information with other neurons.

Previous animal studies conducted by lead author Benedetta Leuner of Ohio State University showed that an increase of dendritic spines in new mothers' brains was associated with improved cognitive function on a task that requires behavioral flexibility — in essence, enabling more effective multitasking. The dendritic spines increased by about 20 percent in these brain regions in new mothers, according to her findings.

The stress in this new study negated those brain benefits of motherhood, causing the stressed rats' brains to match brain characteristics of animals that had no reproductive or maternal experience.

The stressed rats also had less physical interaction with their babies than did unstressed rats, a behavior observed in human mothers who experience postpartum depression.

"Animal mothers in our research that are unstressed show an increase in the number of connections between neurons. Stressed mothers don't," said Leuner, assistant professor of psychology and neuroscience at Ohio State and lead author of the study. "We think that makes the stressed mothers more vulnerable. They don't have the capacity for brain plasticity that the unstressed mothers do, and somehow that's contributing to their susceptibility to depression."

Leuner described the research during a talk on October 13 in New Orleans at Neuroscience 2012, the annual meeting of the Society for Neuroscience.

Previous research has suggested that there are a number of risk factors for postpartum depression, including hormone fluctuations, prior history of mental illness and environmental factors such as smoking or low socioeconomic status. One of the strongest predictors, however, is chronic stress during pregnancy, so Leuner sought to create an animal model that could help explain brain changes linked to postpartum depression.

"It's devastating not only for the mother, because it affects her well-being, but previous research also has shown that children of depressed mothers have impaired cognitive and social development, may have impaired physical development, and are more likely as adults to have depression or anxiety," she said. "A better understanding of postpartum depression is important to help the mother but also to prevent some of the damaging effects that this disorder can have on the child."

The researchers exposed pregnant rats to stress twice a day by limiting their mobility on some days and on other days placing them in water. For three weeks after the rats gave birth, Leuner and colleagues monitored the rats.

The animals showed classic signs of the effects of stress, including lower than normal weight gain and enlarged adrenal glands, a sign of high stress-hormone production. The mothers stressed during pregnancy also gave birth to smaller pups.

"And they were not very good mothers," Leuner said. After separation from pups for 30 minutes, unstressed mothers would gather up their babies, put them in the nest and nurse them. Stressed mother rats left the pups scattered around, wandered around the cage and fed the babies less frequently. The stressed mother rats also exhibited more floating than unstressed rats in a water test; animals that float rather than swim are showing depressive-like symptoms.

"These findings in rats mimic some of the symptoms that are seen in women with postpartum depression," Leuner said.

An examination of the animals' brains showed that the rats exposed to chronic stress did not grow the additional dendritic spines in the hippocampus and prefrontal cortex that the unstressed mother rats did. The stressed rats' brains more closely resembled the brains of control rats that had never been mothers.

"We don't yet know what the exact trigger is for the increase in spines in motherhood, but we know that the increase goes away with stress," Leuner said.

She is continuing the work by investigating whether the beneficial effects of motherhood on cognitive functions are also blocked in mothers who are exposed to pregnancy stress as well as whether hormonal factors play a role.

This work was supported by the National Institute of Mental Health and a Brain & Behavior Research Foundation Young Investigator Award. Leuner co-authored the presentation with Peter Fredericks of Ohio State's Department of Psychology.

A brain pathway that is stimulated by traumatic or fearful experiences can be disrupted by two compounds that show promise for preventing post-traumatic stress disorder, Indiana University researchers reported.

In a presentation prepared for the Neuroscience 2012 scientific conference in New Orleans Oct. 13 to 17, Anantha Shekhar and colleagues from IU reported the results of experiments with rats using a standard methodology called a conditioned fear test.

The neural signaling activated by fearful experiences — a process that also is involved in learning and in memory formation — begins when the neurotransmitter glutamate activates a receptor called NMDA, resulting in a later protein reaction involving production of nitrous oxide, another chemical messenger in the brain.

The two small molecules tested, known as IC87201 and ZL006, are known to disrupt such nitrous oxide production.

In the experiment, rats treated with either of the two compounds showed significantly less fear response than the untreated rats, the researchers reported.

The results, the researchers said, supported their hypothesis that the NMDA-mediated nitrous oxide production is important in successful formation of fear memories, and disrupting that interaction could potentially offer a means of preventing long-term post-traumatic stress disorder symptoms

Repeated intense activation of the brain network for fear makes it vulnerable to developing hypersensitivity, said Shekhar, Raymond E. Houk Professor of Psychiatry and director of the Indiana Clinical and Translational Sciences Institute.

"The majority of people who have a traumatic event, perhaps about 80 percent, will have some post-traumatic stress disorder symptoms for a few days. Only about 20 percent will have long-term problems, but currently there is no way to predict who those people will be," Shekhar said.

With that uncertainty, it would be appropriate to administer the treatment to all traumatized patients within a few hours of the incident, such as when a person arrives at an emergency room after an accident or a field hospital after a military incident, he said.

The next steps would be to optimize compounds and begin drug development efforts, Shekhar said.

Shekhar will discuss "Post-trauma disruption of nNOS-PSD95 protein-protein interaction is an effective means to ameliorate conditioned fear," on October 15.

The ability to anticipate future events allows us to plan and exert control over our lives, but it may also contribute to stress-related increased risk for the diseases of aging, according to a study by UCSF researchers.

In a study of 50 women, about half of them caring for relatives with dementia, the psychologists found that those most threatened by the anticipation of stressful tasks in the laboratory and through public speaking and solving math problems, looked older at the cellular level. The researchers assessed cellular age by measuring telomeres, which are the protective caps on the ends of chromosomes. Short telomeres index older cellular age and are associated with increased risk for a host of chronic diseases of aging, including cancer, heart disease and stroke.

"We are getting closer to understanding how chronic stress translates into the present moment," said Elissa Epel, PhD, an associate professor in the UCSF Department of Psychiatry and a lead investigator on the study. "As stress researchers, we try to examine the psychological process of how people respond to a stressful event and how that impacts their neurobiology and cellular health. And we're making some strides in that."

The researchers also found evidence that caregivers anticipated more threat than non-caregivers when told that they would be asked to perform the same public speaking and math tasks. This tendency to anticipate more threat put them at increased risk for short telomeres. Based on that, the researchers propose that higher levels of anticipated threat in daily life may promote cellular aging in chronically stressed individuals.

"How you respond to a brief stressful experience in the laboratory may reveal a lot about how you respond to stressful experiences in your daily life," said Aoife O'Donovan, PhD, a Society in Science: Branco Weiss Fellow at UCSF and the study's lead author. "Our findings are preliminary for now, but they suggest that the major forms of stress in your life may influence how your respond to more minor forms of stress, such as losing your keys, getting stuck in traffic or leading a meeting at work. Our goal is to gain better understanding of how psychological stress promotes biological aging so that we can design targeted interventions that reduce risk for disease in stressed individuals. We now have preliminary evidence that higher anticipatory threat perception may be one such mechanism."

The study will be published in the May issue of the journal Brain, Behavior and Immunity.

Research on telomeres, and the enzyme that makes them, was pioneered by three Americans, including UCSF molecular biologist and co-author on this manuscript Elizabeth Blackburn, PhD, who co-discovered the telomerase enzyme in 1985. The scientists received the Nobel Prize in Physiology or Medicine in 2009 for this work.

The research related to anticipation was funded by grants from the Division of Behavioral and Social Research at the National Institute of Aging/National Institutes of Health and Bernard and Barbro Foundation as well as by a Society in Science: Branco Weiss Fellowship.