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Childhood Aggression Linked to Deficits in Executive Function

Sat, 03/17/2018 - 9:00am

A new study has found that elementary school children with reduced cognitive skills for planning and self-restraint are more likely to show increased aggression in middle childhood.

Children with lower executive function — a measure of cognitive skills that allow a person to achieve goals by controlling their behavior — were more likely to show physical, relational, and reactive aggression in later years, but not proactive aggression, according to the study.

The increased aggression, which was observed in both boys and girls, may be partly due to an increased tendency for anger in these children, researchers noted.

The findings suggest that helping children to increase their executive function could reduce their aggression, researchers add.

In the new study, researchers at the University of Potsdam in Germany investigated the relationship between childhood executive function and different types of aggression to see if deficits in executive function could predict aggressive behavior in later years.

The research team assessed German primary school children between the ages of six and 11 at three time points: the start of the study, about a year later, and around three years later. The children completed behavioral tasks to reveal different aspects of their executive function, including memory, planning abilities, and self-restraint, researchers reported.

The researchers also asked the children’s teachers to record their tendency for different types of aggression. These included physical aggression, relational aggression (where a child might socially exclude someone or threaten to end a friendship), reactive aggression (where a child reacts aggressively to provocation), and proactive aggression (where a child is aggressive in “cold blood” without being provoked).

Finally, the children’s parents completed a survey detailing how easily the children tended to get angry.

“We found that deficits in executive function affected later physical and relational aggression,” said Dr. Helena Rohlf, the lead author on the study. “The more deficits children showed at the start of the study, the higher their aggression one and three years later.”

Rohlf and her colleagues also found that an increased tendency for anger in children with reduced executive function may partly explain their increased aggression in later years. Furthermore, deficits in executive function were related to increased reactive aggression over time, but not proactive aggression, she noted.

“This ties in with the idea of proactive aggression as cold-blooded, planned aggression,” said Rohlf. “Executive function allows children to behave in a planned and deliberate fashion, which is characteristic of proactive aggression.”

The research team also found that executive function had similar effects on aggression in girls and boys.

“We found that although aggressive behavior was more common among boys, the links between executive function, anger, and aggression seem to be similar for girls and boys,” said Rohlf.

The results suggest that training programs that help children increase their executive function and manage their anger could reduce their aggression.

The researchers said they plan to conduct further studies to see if their results also apply to children with serious levels of aggression.

The study was published in the open-access journal Frontiers in Behavioral Neuroscience.

Source: Frontiers in Behavioral Neuroscience

AI Can Determine Gender by Smile Motion

Sat, 03/17/2018 - 8:00am

The difference between how men and women form their mouths to smile has allowed artificial intelligence (AI) to automatically determine gender by analyzing the underlying muscle movements alone, according to new research by the University of Bradford in the U.K.

Although automatic gender recognition is already in existence, current methods analyze static images and compare fixed facial features. The new study is the first to use the dynamic movement of the smile to automatically distinguish between men and women.

For the study, the researchers mapped 49 points on the face, primarily around the eyes, mouth, and down the nose. They used this information to study how the face changes as we smile caused by the underlying muscle movements. This involves two types of movements: the change in distance between the different points as well as the ‘flow’ of the smile — how much, how far, and how fast the different points on the face moved as the smile was formed.

Next, the researchers looked at whether there were any notable differences between men and women. They found that there were, with women’s smiles being more expansive.

“Anecdotally, women are thought to be more expressive in how they smile, and our research has borne this out. Women definitely have broader smiles, expanding their mouth and lip area far more than men,” said lead researcher Professor Hassan Ugail from the University of Bradford.

Based on this analysis, the researchers developed a new algorithm and tested it on video footage of 109 people as they smiled. The computer was able to correctly determine gender in 86 percent of cases, and the team believes the accuracy could easily be improved.

“We used a fairly simple machine classification for this research as we were just testing the concept, but more sophisticated AI would improve the recognition rates,” said Ugail.

Although the underlying purpose of this research was to enhance machine learning capabilities, the new findings have raised a number of intriguing questions that the team hopes to investigate in future projects: One is how the machine might respond to the smile of a transgender person and the other is the impact of plastic surgery on recognition rates.

“Because this system measures the underlying muscle movement of the face during a smile, we believe these dynamics will remain the same even if external physical features change, following surgery for example,” said Ugail. “This kind of facial recognition could become a next-generation biometric, as it’s not dependent on one feature, but on a dynamic that’s unique to an individual and would be very difficult to mimic or alter.”

The study is published in The Visual Computer: International Journal of Computer Graphics.

Source: University of Bradford


Ketamine Nasal Spray for Depression Runs Into Problems

Sat, 03/17/2018 - 7:00am

Many studies have shown ketamine to be a promising treatment for those suffering from severe depression, but figuring out how to safely administer the drug has been a challenge for researchers. One hopeful delivery method was a nasal spray device because of its ease-of-use and the fact that it is less invasive than other methods such as injection.

But a new Australian study published in the Journal of Psychopharmacology reveals some unexpected problems with the nasal spray method. In particular, the study shows the unpredictable nature of intranasal ketamine tolerance from one person to the next.

“It’s clear that the intranasal method of ketamine delivery is not as simple as it first seemed,” said lead author Professor Colleen Loo at the University of New South Wales (UNSW), who is based at Black Dog Institute.

“Many factors are at play when it comes to nasal spray ketamine treatments. Absorption will vary between people and can fluctuate on any given day within an individual based on such things as mucous levels in the nose and the specific application technique used.”

The pilot trial aimed to analyze the effectiveness of repeated doses of ketamine through an intranasal device amongst 10 volunteers with severe depression, ahead of a larger randomized controlled trial.

First, the participants were given extensive training in proper self-administration techniques before receiving either a course of eight ketamine treatments or an active control over a period of four weeks, under supervision at the study center.

Following the observation of each patients’ initial reaction to the nasal spray, the dosages were adjusted to include longer time intervals between sprays.

However, the trial had to be put on hold after testing with five participants resulted in unexpected problems with tolerability. Side effects included high blood pressure, psychotic-like effects, and motor incoordination which left some participants unable to continue to self-administer the spray.

“Intranasal ketamine delivery is very potent as it bypasses metabolic pathways, and ketamine is rapidly absorbed into the bloodstream,” said Loo. “But as our findings show, this can lead to problems with high peak levels of ketamine in some people causing problematic side effects.”

“Other recent studies have questioned whether changes to ketamine’s composition after being metabolised into derivative compounds may actually deliver useful therapeutic effects. It remains unclear whether ketamine nasal sprays can be safely relied upon as a treatment for patients with severe depression.”

Previous research led by Loo last year revealed the success of ketamine’s antidepressant effects in elderly patients when delivered in repeated doses, which were adjusted on an individual basis and given by the subcutaneous method (injections under the skin).

“Our prior research has shown that altering the dose on an individual patient basis was important. However, we wanted to see if a simpler approach using a set dose of ketamine for all people and administered by nasal spray could work just as well in this latest pilot,” said Loo.

“More research is needed to identify the optimal level of ketamine dosage for each specific application method before nasal sprays can be considered a feasible treatment option.”

The researchers are now recruiting participants for the world’s largest independent trial of ketamine to treat depression, to determine the safety and effects of repeated dosing using subcutaneous injections.

Source: University of New South Wales

Very Fit Middle-Aged Women May Reduce Risk of Later Dementia

Sat, 03/17/2018 - 6:00am

Women with a high level of physical fitness at middle age were 88 percent less likely to develop dementia decades later, compared to women who were moderately fit, according to a new study.

Published in Neurology, the medical journal of the American Academy of Neurology, the study also found that when highly fit women did develop dementia, they developed the disease an average of 11 years later than women who were moderately fit, or at age 90 instead of age 79.

“These findings are exciting because it’s possible that improving people’s cardiovascular fitness in middle age could delay or even prevent them from developing dementia,” said study author Helena Hörder, Ph.D., of the University of Gothenburg in Gothenburg, Sweden.

“However, this study does not show cause and effect between cardiovascular fitness and dementia, it only shows an association. More research is needed to see if improved fitness could have a positive effect on the risk of dementia and also to look at when during a lifetime a high fitness level is most important.”

For the study, 191 women with an average age of 50 took a bicycle exercise test until they were exhausted to measure their peak cardiovascular capacity. The average peak workload was measured at 103 watts.

According to researchers, 40 women met the criteria for a high fitness level at 120 watts or higher. Another 92 women were in the medium fitness category, while 59 women were in the low fitness category. That was defined as a peak workload of 80 watts or less, or having their exercise tests stopped because of high blood pressure, chest pain, or other cardiovascular problems.

Over the next 44 years, the women were tested for dementia six times. During that time, 44 of the women developed dementia.

According to the study’s findings, five percent of the highly fit women developed dementia, compared to 25 percent of moderately fit women and 32 percent of the women with low fitness.

The highly fit women were 88 percent less likely to develop dementia than the moderately fit women, researchers discovered.

Among the women who had to stop the exercise test due to problems, 45 percent developed dementia decades later.

“This indicates that negative cardiovascular processes may be happening in midlife that could increase the risk of dementia much later in life,” Hörder said.

Limitations of the study include the relatively small number of women involved, all of whom were from Sweden, so the results may not be applicable to other populations, Hörder said. Also, the women’s fitness level was measured only once, so any changes in fitness over time were not captured, she noted.

Source: The American Academy of Neurology 

Structural Brain Differences for Transgender People

Fri, 03/16/2018 - 7:45am

A new study reveals that transgender people have variations in the size or volume of certain brain areas. Researchers at the University of São Paulo’s Medical School (FM-USP) in Brazil used magnetic resonance imaging (MRI) to assess the brain composition of transgender individuals.

The investigators performed a structural analysis in search of differences in gray and white matter volume based on MRI scans of the brains of 80 individuals between 18 and 49 years of age and found biological differences.

For the study, investigators created four groups of 20 each: cisgender women, cisgender men, transgender women who had never used hormones, and transgender women who had used hormones for at least a year.

The descriptor cisgender means or relates to a person whose sense of personal identity and gender corresponds with their birth sex.

Variations in the volume of the brain region called the insula in both hemispheres for both groups of transgender women. This discovery is insightful as the insula plays a key role in body image and self-awareness, among other things. Autonomic control, homeostatic information, and visceral sensations are processed within the central nervous system by the insula.

“It would be simplistic to make a direct link with transgender, but the detection of a difference in the insula is relevant since trans people have many issues relating to their perception of their own body because they don’t identify with the sex assigned at birth, and in addition, they unfortunately suffer discrimination and persecution,” said Professor Geraldo Busatto , an associate researcher in the study.

The study was supported by the São Paulo Research Foundation and appears in the journal Scientific Reports.

An important finding from the study is that it shows transgender “doesn’t just refer to different kinds of behavior that people develop”, according to Carmita Abdo, coordinator of the Sexuality Research Program (ProSex) at the Psychiatry Institute of Hospital das Clínicas and principal investigator of the study.

“We observed specificities in the brains of trans individuals, an important finding in light of the idea of gender ideology. The evidence is building up that it’s not a matter of ideology. Our own research based on MRI scans points to a detectable structural basis,” Abdo said.

Because both groups of trans women presented a variation of the insula volume, the authors hypothesized that this finding might to be a characteristic of trans women. Another conclusion of the study was that this particular feature could not be explained by hormone treatment.

Previous studies have found that sexual differentiation of the brain in transgender individuals does not accompany differentiation in the rest of the body.

“We found that trans people have characteristics that bring them closer to the gender with which they identify and [that] their brains have particularities, suggesting that the differences begin to occur during gestation,” said Giancarlo Spizzirri, first author of the study.

The study showed that the size of the insula was not smaller in transgender women than in cisgender men, but its volume was reduced in transgender women compared to cisgender women.

The researchers stressed that reduced gray matter volume in a brain region does not necessarily mean the region in question contains fewer nerve cells.

“The various gray matter brain regions contain a mass of synapses and nerve endings (called neuropils) that can change volume dynamically. For example, at any time during one’s life, a brain region’s density may increase owing to more activity, leading to a subtle rise in the volume of local gray matter,” said Busatto.

The finding cannot be seen as indicating specificity, however. “The insula is a region with multiple elements,” he stressed.

Spizzirri explains that “there’s no such thing as a typically female or male brain.” “There are slight structural differences, which are far more subtle than the difference in genitals, for example. Brain structures vary greatly among individuals,” he noted.

The study is expected to stimulate interest in research on the brain structure of transgender people.

Although the use of MRI scans has increased in recent decades few such studies have focused on transgender people. “It’s a new research field, and this study puts Brazil among the pioneers,” Abdo said.

“On the other hand, the Federal Board of Medicine in Brazil has had guidelines on how to work with the needs of transgender individuals in clinical and surgical practice since 1997. These guidelines are periodically updated and adapted in response to new knowledge.”

“We hope this study will be replicated with larger samples, but right now, it can be said that the hypothesis of transgender development is supported and merits investigation,” she added.

The researchers plan to conduct more studies. A key interest is determining the stage of development in which differences occur.

“Having detected these differences, we should try to find out when they begin to emerge. Among other points, it would be interesting to study [the] brain scans of children and young adults with transgender characteristics and compare them with the scans of adult trans women.”

Source: University of São Paulo

Educational Achievements Overcome Effects of Child Abuse

Fri, 03/16/2018 - 7:00am

When youth experience emotional or child abuse they have an elevated risk to commit crimes later in life. New research discovers education and academic achievement can lessen this risk of crime.

Researchers at the University of Michigan and University of Washington found that when formerly abused children achieve good grades and don’t skip school, the likelihood of self-reported, chronic criminal behaviors declines significantly.

This new ongoing study is one of the few in the nation to follow the same individuals over several decades to learn about how child maltreatment — described as physical, emotional, and sexual abuse, as well as neglect — impacts development and how some are resilient.

“Child abuse is a risk factor for later antisocial behavior,” said study co-author Todd Herrenkohl, the Marion Elizabeth Blue Professor of Child and Family at the University of Michigan School of Social Work.

The study, whose other authors are University of Washington researchers Martie Skinner and Ashley Rousson, appears in the Journal of Interpersonal Violence.

“Education and academic achievement can lessen the risk of crime for all youth, including those who have been abused (encountered stress and adversity).”

In addition to crime/antisocial behavior, the researchers also investigated effects on physical and mental health, drug and alcohol abuse, intergenerational transmission of violence, and socioeconomic disadvantage.

Previous studies about child maltreatment have not distinguished youth and adult chronic offenders from non-offenders and those who only perform antisocial behavior in adolescence — individuals called desisters.

“Given that offending in adolescence can persist into adulthood if left unaddressed, it is important to identify and act on factors that predispose individuals to ongoing patterns of antisocial behavior,” said Hyunzee Jung, the study’s lead author.

Researchers studied data from 356 people in childhood (ages 18 months to six years) in 1976-1977, school-age (eight years) in 1980-1982, adolescent (18 years) in 1990-1992 and adulthood (36 years) in 2010.

Parent reports, self-reports — which included crime/antisocial behavior — and parent-child interactions measured various types of abuse and neglect, and responses also factored educational experiences and criminal behavior against others or property.

Researchers discovered the abuse led to people more likely to commit crimes, but this was not the case for those who had been neglected in their early years.

Successful school experiences kept teens from both committing crimes and having antisocial behaviors. But for youths suspended in grades seven to nine, the chronic offending habits and antisocial behaviors continued later in life, the investigators report.

Herrenkohl said the primary prevention of child abuse is a critical first step to reducing antisocial behavior at the transition from adolescence into adulthood.

“Strategies focused on helping school professionals become aware of the impacts of child abuse and neglect are critical to building supportive environments that promote resilience and lessen risk for antisocial behavior,” he said.

Source: University of Michigan

Nightmares Relatively Common Among Military Personnel

Fri, 03/16/2018 - 6:15am

New research reveals that a high percentage of military personnel with sleep disturbances met the criteria for nightmare disorder. However, few of them reported nightmares as a reason for sleep evaluation. The presence of a nightmare disorder increases the risk of other sleep and mental health disorders.

Investigators found that 31 percent of military participants with reported sleep issues had clinically significant nightmares, and trauma-related nightmares occurred in 60 percent of them.

Participants who met criteria for nightmare disorder were five times more likely to have post-traumatic stress disorder (PTSD), four times more likely to have depression, three times more likely to have anxiety, and two times more likely to have insomnia.

Despite their common presence, nightmares were reported as a sleep-related concern by only 3.9 percent of military personnel.

“This research provides a basis for furthering the study and knowledge of nightmares in survivors of traumatic experiences,” said principal investigator Dr. Jennifer Creamer, medical director of the Sleep Medicine Center at Martin Army Medical Center in Fort Benning, Georgia.

“Treatment of nightmares can lead to improvement in sleep, quality of life, and other disorders such as suicidality.”

The study results appear in the Journal of Clinical Sleep Medicine.

Nightmares are vivid, realistic, and disturbing dreams typically involving threats to survival or security, which often evoke emotions of anxiety, fear, or terror. A nightmare disorder may occur when repeated nightmares cause distress or impairment in social or occupational functioning.

According to the authors, this was the largest study to assess clinically significant nightmares in an active duty population referred for the evaluation of sleep disorders. The study involved 493 active duty U.S. military personnel. Participants had a mean age of 38 years, and 78.5 percent were men. Participants predominantly served in the Army (45.6 percent) and Air Force (45.2 percent); 9.2 percent served in the Navy/Marines. Approximately 74 percent of them had been deployed.

Researchers found that those with trauma-related nightmares were more likely to have traumatic brain injury, PTSD, anxiety, and depression.

Nightmares beginning within three months of a trauma are present in up to 80 percent of patients with PTSD, and these post-traumatic nightmares may persist throughout life. Post-traumatic nightmares may take the form of a realistic reliving of a traumatic event or may depict only some of its elements or emotional content.

“Nightmare disorder is highly prevalent but under-recognized in military personnel with sleep disturbances,” said Creamer.

A best practice guide from the American Academy of Sleep Medicine indicates that treatment options for nightmare disorder include medications, most prominently prazosin. Several behavioral therapies also can be effective, such as image rehearsal therapy and other nightmare-focused cognitive behavioral therapy variants.

“Military personnel and health care providers require education that nightmares are not normal and there are treatments available,” added Creamer.

Source: The American Academy of Sleep Medicine/EurekAlert

Teens More Likely to Plead Guilty to Crimes They Didn’t Commit

Fri, 03/16/2018 - 5:30am

Experts are calling for major changes to the juvenile justice system after finding that teenagers are far more likely to plead guilty to crimes they did not commit compared to adults.

New study findings suggest that teens should not be allowed to make deals where they face a lesser charge in return for pleading guilty, because they are less capable of making mature decisions and more likely to be enticed by such an offer — even when they have done nothing wrong.

This is consistent with previous research showing that adolescents are less able to perceive risk and resist the influence of peers because of developmental immaturity.

“It is important to ensure the people accused of crimes have the capacity and freedom to make sensible decisions about whether to plead guilty,” said researcher Dr. Rebecca Helm from the University of Exeter Law School in the U.K..

“Where systems allow defendants to receive a reduced sentence or charge by pleading guilty they need to ensure that defendants are suitably developed to make such decisions and that they have the necessary levels of understanding, reasoning, and appreciation.”

In fact, in both the U.S. and U.K., most criminal convictions occur as the result of guilty pleas, rather than trial. This means that most convictions are the result of decisions made by people accused of crimes rather than jurors.

The study was conducted in the U.S., where a system known as “plea bargaining” is used, but the researchers say their discovery has implications for countries across the world that allow young people accused of crimes to receive a sentence or charge reduction by pleading guilty.

The researchers recommend restricting reductions that may essentially bribe innocent teenagers into pleading guilty. It should also be easier for teens to change pleas after they have been entered.

“We hope this research will lead to plea systems becoming fairer and less coercive for adolescents,” said Helm. “Any restrictions on guilty pleas for adolescents would have to be introduced in a way that avoids harsher average sentences being imposed on adolescents.”

“However, research increasingly suggests that in the same way as they are too young to vote, too young to drink alcohol, and too young to rent a home, perhaps adolescents are too young to plead guilty.”

For the study, Helm and Valerie F. Reyna, Allison A. Franz, and Rachel Z. Novick from Cornell University tested decision-making among people of different ages. They recruited 149 adolescents aged nine to 17 from high schools and middle schools in New York, 200 students from Cornell University aged 18 to 22, and 187 adults from across America.

All participants were given the same hypothetical situation in which they were asked to indicate the decisions they would make if accused of a crime. They were either asked to imagine they were guilty or not guilty of the crime, and were told the approximate likelihood of conviction at trial and the reductions that could be gained by pleading guilty as opposed to being convicted at trial.

The findings show that as people become older, those who are innocent are less likely to plead guilty. For example, innocent teens said they would plead guilty in roughly one-third of cases, while innocent adults indicated that they would plead guilty in just 18 percent of cases.

Importantly, the teens were significantly less influenced in their decision-making by whether or not they were guilty compared to adults. The results also suggest that adolescents are making decisions that do not reflect their values and preferences, including those relating to admitting guilt when innocent, due to developmental immaturity.

Although this was an experiment, the researchers believe the findings have important implications for the juvenile justice system.

Source: University of Exeter

ADHD Meds May Improve Mood in Healthy Humans

Thu, 03/15/2018 - 7:00am

New research finds that when healthy people take attention-deficit hyperactivity disorder (ADHD) drugs, the medication stimulates the release of a chemical in the brain associated with positive emotion.

ADHD medications cause a surge in the neurotransmitter glutamate in key parts of the brain. Subsequently, this increase is associated with changes in positive emotion.

The findings not only provide clues about how these drugs affect healthy brains, they also hint at a previously undiscovered link between glutamate and mood.

“This is the first time that an increase in brain glutamate in response to psychostimulant drugs has been demonstrated in humans,” said Dr. Tara White, an assistant professor in the Brown University School of Public Health and lead author of the new study.

“That’s important since glutamate is the major neurotransmitter responsible for excitation in the brain, and affects learning and memory.”

Even more interesting, White said, the rise in glutamate predicted the magnitude and the duration of positive emotional responses to the drug.

“Given the timing of these effects — the glutamate effect comes first, and the positive emotion comes later — this could indicate a causal link between glutamate and positive emotion,” White said. “I think what we’re seeing here is not just a drug effect, it’s how positive emotion works in humans.”

The research appears in the journal Neuropsychopharmacology.

Millions of kids nationwide take prescription medication to treat ADHD. But in addition to prescribed usage, there’s a thriving black market for these drugs, which young people use to improve attention, mood, and work and school performance. Yet little is known about what effects these drugs have on healthy brains, White said.

In this new study, subjects were first screened for mental and physical health and then underwent MRI spectroscopy scans designed to detect the concentration of neural compounds in specific regions of their brain.

From the medical literature on psychostimulants, White and her team wanted to look in the anterior cingulate cortex, which is a “hub” brain region that connects multiple brain networks involved in emotion, decision-making, and behavior.

They found that two ADHD medications, d-amphetamine and Desoxyn, significantly increased the overall amount of glutamate in the right dorsal anterior cingulate cortex, even after controlling for possible alternative contributing factors, such as volume of gray matter in the region.

The rise in brain glutamate predicted both the duration and the intensity of positive emotion, measured by participant ratings about whether they liked the drug or felt high after consuming it.

Researchers caution that while this was a placebo-controlled study, the findings only suggest an association between glutamate and positive mood, and not necessarily a causal relationship.

However, the fact that the mood changes consistently followed changes in glutamate is suggestive of a cause and effect relationship, though more research is necessary.

Glutamate is the most abundant neurotransmitter in the brain, White said, and its roles in learning and memory are well established. A potential link between glutamate and mood would be a novel finding.

“This is the first time we’ve seen a link between increases in brain glutamate and increases in positive emotion in healthy people, with both changes happening in real time,” said White. “I think it’s going to open up a whole new way of thinking about emotion in humans.”

The research also found evidence of gender differences in drug effects. Women in the sample showed a larger increase in glutamate compared to the men in the sample. Women also responded more strongly to Desoxyn, compared to d-amphetamine.

The gender difference is consistent with prior studies in animals, which show greater stimulant drug effects in females compared to males. The differences between the two drugs also indicate that ADHD medications can have different effects on glutamate and other compounds in the brain.

White and her colleagues believe the medications influence the development of more or new glutamate, rather than just improving the uptake of what is already available. With further research, new data could help scientists to better understand how individuals respond differently to drugs, and changes in positive emotion over time.

“[The] present findings provide the first evidence in humans that drug-induced changes in [glutamate] correlate with subjective experiences of drug liking and drug high following drug ingestion,” White and colleagues wrote.

Source: Brown University

Study Finds No Link Between Teen Suicide Risk and Flu Drug

Thu, 03/15/2018 - 6:15am

In a new study, researchers did not find an increased risk of suicide among adolescent patients taking the drug oseltamivir (Tamiflu), the only commercially available medication approved by the U.S. Food and Drug Administration (FDA) to treat the flu.

After the drug’s approval in 1999, case reports began to emerge of abnormal behavior in adolescents who had taken the drug. This led the FDA to require that the medication come with a warning label of potential neuropsychiatric side effects, such as hallucinations, delirium, self-harm, and suicide.

So far, clinical studies examining a link between Tamiflu and neuropsychiatric side effects in children, including suicide, have been inconclusive, however. They have also been limited by methodology and potential confounding factors, according to researchers.

In an effort to fill this gap, researchers from the University of Illinois at Chicago (UIC) College of Pharmacy retrospectively studied the association between the use of Tamiflu and the most consequential of those reported side effects: suicide.

“I think physicians will welcome a large, rigorous study on this topic and factor this information into their decision-making process,” said corresponding author Dr. James Antoon, assistant professor of clinical pediatrics in the UIC College of Medicine.

“While this study addresses suicide, there are still many other questions about other possible neuropsychiatric side effects of the drug, which we plan to study in the future. There are also other reasons to use caution when prescribing the drug, including resistance and efficacy in children.”

First, the researchers identified 21,047 children and teens between the ages of one and 18 who attempted suicide during five recent flu seasons (2009-2013) from a national administrative claims database. Of these, 251 had been exposed to Tamiflu, which was determined based on outpatient pharmacy dispensing data.

The mean age of this group was 15 years, 61 percent were female, and 65 percent had an underlying mental health diagnosis.

“For each of the 251 patients, we assigned the 10-day period immediately before the suicide attempt as the case period and we identified up to four earlier control periods of the same length, in the same flu season,” Antoon said. “This helped us to account for within-person confounders, like depression, mental health, trauma and abuse, and other factors, like race or ethnicity.”

The research team repeated the analysis with flu diagnosis alone (without the use of Tamiflu) to determine whether the infection itself could have been a confounding factor associated with suicide risk.

“The potential link between a drug and suicide is a particularly difficult topic to study,” Antoon said. “Many events, which can happen simultaneously or over time, can influence a person to attempt suicide, as can an illness itself, so it can be difficult to study scientifically.

“That’s why we used a novel method called a case-crossover design,” Antoon said. “This analysis is different because it allowed us to use each individual subject as his or her own comparison — we retrospectively studied how patients behaved when on Tamiflu and compared it to their behavior when they were not taking the drug.”

“We did not find any association between exposure to Tamiflu and suicide in pediatric patients,” Antoon said.

While Antoon believes the study may alleviate some fears health care providers have about prescribing the medication in healthy children, he says doctors will likely continue to prescribe Tamiflu with caution.

The findings are published in the Annals of Family Medicine.

Source: University of Illinois at Chicago

Study: Violent Video Games Do Not Up Adult Aggression

Thu, 03/15/2018 - 5:30am

German researchers have discovered that playing violent action adventure games for prolonged periods does not make adults more aggressive. The finding challenges prior research endorsed by prominent organizations including the American Psychological Association.

Investigators from the Max Planck Institute for Human Development and the University Clinic Hamburg-Eppendorf say the study is the first to investigate the effects of long-term violent video game play. Researchers compared the video-game experience with playing a life simulation game or not playing a video game at all.

The study appear in the journal Molecular Psychiatry.

Previous experimental investigations have shown that a few minutes’ worth of violent video game play can influence a person’s levels of aggression and willingness to help others. But there is reason to believe that these effects were mostly the results of exposure to specific stimuli and subsequent priming that formed part of these studies.

Seventy-seven participants were divided into three groups. The first group of 25 played the violent video game Grand Theft Auto V daily for two months. The second group of 24 played the simulation game The Sims 3 every day for two months, while the final group of 28 did not play any video games for two months.

Before and after the two-month period, lead researcher Dr. Simone Kühn and her team noted the participants’ level of aggression and empathy, interpersonal competencies, impulsivity, anxiety, mood and executive control. These characteristics were all determined using a battery of tests consisting of questionnaires and computerized behavioral assessments.

The researchers found no significant changes in any of the variables assessed, particularly not in the aggression levels over time in any of the three groups. Only three of the 208 statistical tests performed showed any significant changes that could allude to more violent behavior, and these are explained through coincidence.

Two months after the participants stopped playing daily video games, there was still no difference in their aggression levels. This was also true for their measures of empathy, interpersonal competencies, impulsivity, anxiety, mood, and executive control.

“We did not find relevant negative effects in response to violent video game playing,” explained Kühn. “The fact that we assessed multiple domains, not finding an effect in any of them, makes the present study the most comprehensive in the field.”

The results provide strong evidence against the frequently debated negative effects of playing violent video games in adults. Kühn hopes it will provide a more realistic scientific perspective on the effects of violent video gaming in real life, and that similar studies will be done using children as participants.

“The American Psychological Association recently summarized the previous findings on violent video games as indicating that they pose a risk factor for adverse outcomes, including increased aggression and decreased empathy. The present findings of this study clearly contradict this conclusion,” added Kühn.

Source: Springer

Men and Women With Depression Show Opposite Molecular Changes

Wed, 03/14/2018 - 7:45am

New research finds that men and women with major depressive disorder (MDD) have opposite changes in the expression of the same genes. If true, the discovery suggests that men and women may need different types of treatment for depression.

Researchers at the University of Pittsburgh and Centre for Addiction and Mental Health (CAMH), Toronto, Canada, base their conclusion on a new postmortem brain study.

The findings, published in Biological Psychiatry, indicate distinct pathology for men and women.

“This important paper highlights the divergent molecular mechanisms contributing to depression in men and women. It challenges the assumption that a similar diagnosis across people has the same biology,” said John Krystal, M.D., editor of Biological Psychiatry.

This is the first time this unique opposing pathology has been reported.

“While researchers have been examining the brains of depressed subjects for decades, many of these studies included only men,” said lead author Marianne Seney, Ph.D., of University of Pittsburgh. This is despite the differences in MDD between men and women: Women are twice as likely to be diagnosed with MDD, and report greater illness severity and different types of symptoms than men.

The study combined eight published datasets (four in men and four in women) in a meta-analysis. Senior author Etienne Sibille, Ph.D., of CAMH, and colleagues analyzed gene expression levels, which indicate how much protein a gene is producing, in postmortem brain tissue of 50 people with MDD (26 men and 24 women) and the same number of unaffected men and women for comparison.

Most of the genes that had altered expression were changed in only men or only women. However, genes that were altered in both men and women were changed in opposite directions.

Women had increased expression of genes affecting synapse function, whereas men had decreased expression of the same genes. Women had decreases in genes affecting immune function, whereas men had increased expression of these genes.

Additionally, the researchers applied their methods to data from a different set of subjects and replicated the opposing changes.

The analysis focused on three different brain regions that regulate mood — the anterior cingulate cortex, dorsolateral prefrontal cortex, and amygdala — and that are dysfunctional in MDD.

Investigators discovered opposite changes in gene expression were specific to the different brain regions. So if women had increased expression of a particular gene in one region and decreased in another, men showed just the opposite.

Because the study used postmortem brain tissue, the effect of the opposite molecular signatures on how MDD affects men and women differently could not be studied. But the findings support sex-specific pathology in the disorder.

“These results have significant implications for development of potential novel treatments and suggest that these treatments should be developed separately for men and women,” said Seney.

For example, in the paper the authors suggest that new treatments targeting the sex-specific pathology in MDD might suppress immune function in men, or boost its function in women.

Source: Elsevier

Gender Differences Found in Brains of Sleep Apnea Patients

Wed, 03/14/2018 - 7:00am

A new brain imaging study reveals structural brain changes in patients with sleep apnea as well as distinct differences between males and females with the condition.

Obstructive sleep apnea, a disorder which involves disruption of the upper airway, affects about 10 percent of adults. Men are twice as likely to have the condition as women, and symptoms and brain function appear to vary between sexes. When left untreated, the effects of sleep apnea on brain damage increases over time. Its cause is still unknown.

For the study, researchers from the University of California, Los Angeles (UCLA) School of Nursing looked at the brain scans and clinical records of patients who recently had been diagnosed with sleep apnea.

Using high-resolution magnetic resonance imaging (MRI) scans, the researchers analyzed the cortex thickness of 12 women and 36 men who had diagnoses of mild to severe obstructive sleep apnea (who were not being treated for their condition), and compared those findings to 40 male and 22 female healthy controls. The researchers then compared clinical findings of each patient with evidence of cortex thinning.

Not only did they discover several connections between apnea symptoms and thinning of the brain’s cerebral cortex, but they also found distinct differences between men and women when it came to brain structure and concurrent symptoms.

For example, more regions of the superior frontal lobe were thinner in women with apnea than in men with apnea or control groups, which might explain the greater cognitive deficits often found among women with the condition.

In addition, overall cortical thinning could potentially result in poor regulation of the autonomic nervous system and the associated upper-airway breathing dysfunction typically seen in these patients. No sleep apnea patients showed any thickening of the cerebral cortex.

Although previous research has shown a link between brain structure changes and general clinical signs, no studies have definitively linked gender differences in brain structure with apnea symptoms.

The current study is one of the first to reveal significant clinical differences between men and women with sleep apnea, and points to the need for different treatment approaches in addressing these varied symptoms.

Overall, the greater cortex injury in the cognitive centers of women’s brains may help explain why female apnea patients tend to have more severe cognitive problems than men with the condition. In addition, the thinning associated with both men and women who have sleep apnea may be behind the disordered breathing seen in both sexes.

It is still unclear, however, whether these physical brain changes precede the sleep apnea disorder, or worsen sleep apnea’s symptoms as the disorder progresses.

Source: University of California, Los Angeles Health Sciences

Meditation Can Keep Depressive Symptoms from Worsening

Wed, 03/14/2018 - 6:15am

A new primary care study finds that mindfulness meditation training for individuals with subthreshold depression reduces the incidence of major depression and improves depression symptoms.

When a person has subthreshold depression they typically display a group of depressive symptoms but the number, duration, or quality of the symptoms are not present in a sufficient scale to meet the criteria for a diagnosis of major depression.

In the new study, adults with subthreshold depression were randomly assigned to receive either usual care in which there was no psychological intervention (n=116) or a behavioral activation focused on mindfulness training (n=115).

Intervention participants were invited to attend weekly two-hour mindfulness training sessions for eight consecutive weeks.

After a year of training, there was a statistically significant difference in the incidence of major depressive disorder between groups (11 percent in the mindfulness group compared to 27 percent in usual care).

Investigators also discovered mindfulness training had a small effect in reducing depression symptoms (between-group mean difference = 3.85). Other secondary outcomes demonstrated no significant change.

Researchers suggest that, for patients with subthreshold depression who have not had a major depressive episode in the past six months, mindfulness training is a feasible method of preventing major depression.

Future research will compare cost-effectiveness, health service use implications, and acceptability of mindfulness training.

The study appears in the journal Annals of Family Medicine.

Source: Annals of Family Medicine

Suppression of Emotions Can Reduce Negative Memories

Wed, 03/14/2018 - 5:30am

Functional brain imaging has helped scientists understand how emotional regulation influences negative feelings and memories. The technology has allowed researchers to study brain responses when a subject is prompted to suppress negative emotions.

Researchers hope the findings will lead to new methods to combat depression.

Investigators from the University of Illinois used functional MRI to track activity in the brains of 17 individuals undergoing an image-rating task. A control group of 17 performed the same activities without functional MRI.

The study revealed similarities and differences between those who were explicitly told to suppress negative feelings while rating the negativity of negative images and those unconsciously prompted to do so.

The research appears in the journal Neuropsychologia.

Investigators discovered both overt and covert emotional suppression reduced participants’ memory of the negative images one week later. But the two approaches had different effects on participants’ immediate experience of emotions associated with the images, and on how their brains processed the images.

“Our interest in conducting this study started with a desire to identify alternative ways to help people with depression,” said University of Illinois psychology professor Dr. Sanda Dolcos, who conducted the research with graduate student Yuta Katsumi.

“Friends and family of depressed people often say, ‘Get yourself together and control your emotions,’ but this is not so easy,” Dolcos said. “That’s why we are interested in implicit, or unconscious, emotional suppression.”

“People with depression or other mood disorders tend to have trouble distancing themselves from their negative memories,” Katsumi said. “If we can help them remember less or forget those negative memories, then maybe they can reallocate that attention to something more positive in their lives.”

At the beginning of the study, researchers asked participants to rate 180 negative and neutral photos. They then repeated the activity — some after being instructed to dampen their negative emotional responses to negative photos, and some after reading materials designed to unconsciously prompt emotional control.

Both conscious (explicit) and unconscious (implicit) emotional suppression reduced participants’ ability to remember the negative images one week later. However, compared with how they felt when viewing negative images initially, only those explicitly told to inhibit their negative emotions felt less negative when viewing negative photos.

The functional MRI data revealed that explicit, but not implicit, emotional suppression lessened activity in in the amygdala, a brain region that aids in emotional processing.

However, both forms of emotional suppression were associated with reduced functional connectivity in brain regions that help encode emotional memories, the researchers found. This may explain why both explicit and implicit emotional suppression reduced participants’ memory of negative photographs.

“Suppressing emotions appears to reduce negative memories, whether you do that consciously or unconsciously,” Katsumi said.

“But explicit emotional suppression takes effort. You have to have enough cognitive resources to do that, and people with clinical conditions might not be able to afford those resources.”

Source: University of Illinois-Champaign

Therapy Dogs May Ease Stress of College Students

Tue, 03/13/2018 - 7:45am

A new study from the University of British Columbia (UBC) shows that some one-on-one time with a therapy dog can do the trick of boosting student wellness.

Some believe college students are more stressed than ever before. As such, academic centers are taking proactive strategies to provide healthy avenues for students.

“Therapy dog sessions are becoming more popular on university campuses, but there has been surprisingly little research on how much attending a single drop-in therapy dog session actually helps students,” said Emma Ward-Griffin, the study’s lead author and research assistant in the UBC department of psychology.

“Our findings suggest that therapy dog sessions have a measurable, positive effect on the wellbeing of university students, particularly on stress reduction and feelings of negativity.”

In the study, researchers surveyed 246 students before and after they spent time in a drop-in therapy dog session. Students were free to pet, cuddle, and chat with seven to 12 canine companions during the sessions. They also filled out questionnaires immediately before and after the session, and again about 10 hours later.

The researchers found that participants reported significant reductions in stress as well as increased happiness and energy immediately following the session, compared to a control group of students who did not spend time at a therapy dog session. While feelings of happiness and life satisfaction did not appear to last, some effects did.

The study appears in Stress and Health.

“The results were remarkable,” said Dr. Stanley Coren, study co-author and professor emeritus of psychology at UBC.

“We found that, even 10 hours later, students still reported slightly less negative emotion, feeling more supported, and feeling less stressed, compared to students who did not take part in the therapy dog session.”

While previous research suggested that female students benefit from therapy dog sessions more than male students, the researchers found the benefits were equally distributed across both genders in this study.

Since the strong positive effects of the therapy dog session were short-lived, the researchers concluded that universities should be encouraged to offer them at periods of increased stress.

“These sessions clearly provide benefits for students in the short-term, so we think universities should try to schedule them during particularly stressful times, such as around exam periods,” said Dr. Frances Chen, the study’s senior author and an assistant professor of psychology at UBC.

“Even having therapy dogs around while students are working on their out-of-class assignments could be helpful.”

The therapy dog sessions were organized in partnership with UBC’s Alma Mater Society and Vancouver ecoVillage, a non-profit organization that provides therapeutic services, including therapy dog sessions, and mental health wellness services.

Source: University of British Columbia

Smoking Tied to Higher Risk of Psychosis in Youth

Tue, 03/13/2018 - 7:00am

New research suggests that a young person smoking at least 10 cigarettes a day increases the risk of psychosis when compared to non-smoking young people.

The risk is also raised if the smoking starts before the age of 13.

Finnish researchers analyzed a comprehensive database of over 9,000 individuals born in North Finland in 1986. The results were recently published in the journal Acta Psychiatrica Scandinavica.

“This was an extensive longitudinal study based on the general population. It revealed that daily and heavy smoking are independently linked to the subsequent risk of psychoses, even when accounting for previous psychotic experiences, the use of alcohol and drugs, substance abuse, and the parents’ history of psychoses.

Smoking begun at an early age was a particularly significant risk factor. Based on the results, prevention of adolescent smoking is likely to have positive effects on the mental health of the population in later life,” said study leader and Academy Research Fellow, Professor Jouko Miettunen.

The aim of the study was to investigate whether young people’s daily cigarette smoking is associated with a risk of psychoses, after accounting for several known, confounding factors, such as alcohol and drug use, the hereditary taint of psychoses and early symptoms of psychosis.

Fifteen-sixteen year-old members of the 1986 cohort were invited to participate in a follow-up study carried out in 2001-2002. The final sample included 6,081 subjects who answered questions on psychotic experiences and alcohol and drug use. The follow-up continued until the subjects had reached the age of 30.

The research team has also conducted a study on cannabis use, which has been published in The British Journal of Psychiatry. That study found that teenage cannabis use is associated with an increased risk of psychosis. It also showed that people who had used cannabis and had psychotic experiences early in life experienced more psychoses during the period of study.

“We found that young people who had used cannabis at least five times had a heightened risk of psychoses during the follow-up, even when accounting for previous psychotic experiences, use of alcohol and drugs and the parents’ history of psychoses.

“Our findings are in line with current views of heavy cannabis use, particularly when begun at an early age, being linked to an increased risk of psychosis. Based on our results, it’s very important that we take notice of cannabis-using young people who report symptoms of psychosis. If possible, we should strive to prevent early-stage cannabis use,” says Antti Mustonen, Lic. Med.

The two studies were part of Jouko Miettunen’s research project “Trends and interactions of risk factors in psychotic disorders – Northern Finland birth cohort studies 1966 and 1986”, which was funded by the Academy of Finland.

The published articles are part of Antti Mustonen’s forthcoming doctoral thesis on the link between alcohol and drug use and the risk of psychoses. In addition to researchers from the University of Oulu, the investigative team included members from the University of Cambridge and the University of Queensland.

Source: Academy of Finland/EurekAlert

Mix of Some Personality Traits May Up Risk of Compulsive Social Media Use

Tue, 03/13/2018 - 6:30am

In a new study, researchers explored how the interaction of specific personality traits can impact the likelihood of developing compulsive Internet use, in particular to social networking sites.

“There has been plenty of research on how the interaction of certain personality traits affects addiction to things like alcohol and drugs,” said Binghamton University School of Management assistant professor Dr. Isaac Vaghefi.

“We wanted to apply a similar framework to social networking addiction.”

Vaghefi, and co-researcher Dr. Hamed Qahri-Saremi of DePaul University in Chicago, collected self-reported data from nearly 300 college-aged students. They found that three personality traits in particular — neuroticism, conscientiousness, and agreeableness — were related to social network addiction.

These three personality traits are part of the five-factor personality model, a well-established framework for  understanding the human personality.

Researchers found that the two other traits in the model — extraversion and openness to experience — did not play much of a role in the likelihood of developing a social network addiction.

In addition to testing the effect the singular traits had, the investigators studied how the traits interact with one another as they relate to social network addiction.

“It’s a complex and complicated topic. You can’t have a simplistic approach,” said Vaghefi.

Study authors note that on their own, the personality traits of neuroticism and conscientiousness have direct negative and positive effects on the likelihood of developing a social network addiction.

Researchers found that neuroticism (the extent to which people experience negative emotions such as stress and anxiety) seemed to increase the likelihood of developing an addiction to social network sites.

On the other hand, higher amounts of conscientiousness (having impulse control and the drive to achieve specific goals) seemed to decrease the likelihood of developing a social network addiction.

But when tested together, they found that neuroticism seemed to moderate the effect of conscientiousness as it relates to social network addiction.

The finding is complex because someone can simultaneously be highly neurotic and conscientious. Researchers found that even if someone is able to practice self-discipline and regularly persists at achieving goals, the fact that they may also be a stressful and anxious person often overrides the perceived control they may have over social network use.

This moderation effect could cause a conscientious person to be more likely to develop an addiction to social networking sites.

Researchers found that agreeableness alone, the degree to which someone is friendly, empathetic, and helpful, didn’t have a significant effect on social network addiction — but this changes when combined with conscientiousness.

A combination of low levels of both agreeableness and conscientiousness (someone can be both generally unsympathetic and irresponsible) often are related to a higher likelihood of social network addiction. Paradoxically, the opposite combination of high levels of both agreeableness and conscientiousness also increase risk of social network addiction.

Vaghefi said this unexpected finding could be explained from a “rational addiction” perspective, meaning some users are intentionally using more of a social network to maximize the perceived benefits of it.

For example, he said an agreeable and friendly person may be making a very conscientious decision to use social networks more in order to interact with their friends, as they make it a deliberate goal to flourish those relationships through the use of social networks.

This is unique because this addiction would not be a result of irrationality or a lack of impulse control, as is often associated with addiction. Rather, a person would be developing an addiction through a rational and well-meaning process.

Vaghefi hopes that based on this research, people will look at the “whole picture” when it comes to how personality traits impact social networking addiction.

“It’s more of a holistic approach to discover what kind of people are more likely to develop an addiction,” said Vaghefi.

“Rather than just focusing on one personality trait, this allows you to look at an all-inclusive personality profile.”

Vaghefi’s paper was presented at the 51st Hawaii International Conference on Systems Science.

Source: Binghamton University/EurekAlert

Pursuing Happiness May Make You Unhappy

Tue, 03/13/2018 - 5:30am

People who pursue happiness tend to feel like they don’t have enough time in the day, and this paradoxically makes them feel unhappy, according to a new study published in the journal Psychonomic Bulletin & Review.

Researchers from the U.S. and Canada conducted four experiments in which they studied how the pursuit of happiness, as well as the state of being happy, influenced people’s perception of time. They discovered that the act of pursuing happiness caused the participants to think of time as scarce.

“Time seems to vanish amid the pursuit of happiness, but only when seen as a goal requiring continued pursuit,” said researchers Aekyoung Kim of Rutgers University and Sam Maglio, Ph.D., of the University of Toronto Scarborough. “This finding adds depth to the growing body of work suggesting that the pursuit of happiness can ironically undermine well-being.”

For the study, some participants were encouraged to think of happiness as a goal they needed to attain. These participants were either asked to make a list of things that would make them happy, or they were prompted to try to make themselves feel happy while watching a dull movie about building bridges.

The rest of the participants came to think of happiness as a goal that they had already achieved, by watching a slapstick comedy (rather than the bridge movie) or by listing items in their lives that have already brought them happiness. Next, all participants reported how much free time they felt they had.

The findings reveal that a person’s perception of time scarcity is influenced by their pursuit of (often unattainable) happiness. Participants who felt they had attained their goal of being happy were less likely to feel that time was scarce.

According to the researchers, the findings suggest that while happiness can impair positive emotions, it need not necessarily do so. Instead, if someone believes they have achieved happiness, they are left with the time to appreciate this, for instance by keeping a gratitude journal.

The study also highlights the fact that people have different concepts of happiness, which in turn may well influence how they perceive the time they have to achieve happiness.

“Because engaging in experiences and savoring the associated feelings requires more time compared with merely, for instance, buying material goods, feeling a lack of time also leads people to prefer material possessions rather than enjoying leisure experiences,” said the researchers, who add that feeling pressed for time often also makes people less willing to spend time helping others or volunteering.

“By encouraging people to worry less about pursuing happiness as a never-ending goal, successful interventions might just end up giving them more time and, in turn, more happiness.”

Source: Springer

Mice Study Shows How Others’ Stress Can Alter Brain Just Like Real Thing

Mon, 03/12/2018 - 7:45am

New Canadian research using mice shows that stress transmitted from others can change the brain in the same way as real stress does. The study also shows that the effects of stress on the brain are reversed in female mice — but not males — following a social interaction.

Jaideep Bains, Ph.D., and his team at the University of Calgary studied the effects of stress in pairs of male or female mice. They removed one mouse from each pair and exposed it to a mild stress before returning it to its partner.

They then examined the responses of a specific population of cells, specifically CRH neurons which control the brain’s response to stress, in each mouse. Networks in the brains of both the stressed mouse and naïve partner were altered in the same way.

“Brain changes associated with stress underpin many mental illnesses including PTSD, anxiety disorders, and depression,” said Bains, professor in the Department of Physiology and Pharmacology and member of the Cumming School of Medicine’s Hotchkiss Brain Institute (HBI).

“Recent studies indicate that stress and emotions can be ‘contagious’. Whether this has lasting consequences for the brain is not known.”

Toni-Lee Sterley, Ph.D., a postdoctoral associate in Bains’ lab and the study’s lead author comments, “What was remarkable was that CRH neurons from the partners, who were not themselves exposed to an actual stress, showed changes that were identical to those we measured in the stressed mice.”

The team then used optogenetic approaches to engineer these neurons so that they could either turn them on or off with light. When the team silenced these neurons during stress, they prevented changes in the brain that would normally take place after stress.

When they silenced the neurons in the partner during its interaction with a stressed individual, the stress did not transfer to the partner. Remarkably, when they activated these neurons using light in one mouse, even in the absence of stress, the brain of the mouse receiving light and that of the partner were changed just as they would be after a real stress.

The team discovered that the activation of these CRH neurons causes the release of a chemical signal, an “alarm pheromone,” from the mouse that alerts the partner.

The partner who detects the signal can in turn alert additional members of the group. This propagation of stress signals reveals a key mechanism for transmission of information that may be critical in the formation of social networks in various species.

Another advantage of social networks is their ability to buffer the effects of adverse events. The Bains team also found evidence for buffering of stress, but this was selective.

They noticed that in females the residual effects of stress on CRH neurons were cut almost in half following time with unstressed partners. The same was not true for males.

Bains suggested these findings may also be present in humans. “We readily communicate our stress to others, sometimes without even knowing it. There is even evidence that some symptoms of stress can persist in family and loved ones of individuals who suffer from PTSD. On the flip side, the ability to sense another’s emotional state is a key part of creating and building social bonds.”

The study, which appears in the journal Nature Neuroscience, indicates that stress and social interactions are intricately linked. The consequences of these interactions can be long-lasting and may influence behaviors at a later time.

Source: University of Calgary/EurekAlert