Double burden of paid and unpaid labor leading to poorer mental health in women
New research reveals unpaid labor is associated with poorer mental health in employed women, but the effects are less apparent for men
September 1, 2022
University of Melbourne
Women still do the bulk of unpaid work at home while also holding down a job. A new review finds this double burden is taking a toll on their mental health.
New research reveals unpaid labour is associated with poorer mental health in employed women, but the effects are less apparent for men.
Published in the Lancet Public Health, University of Melbourne researchers have conducted a review -- the first of its kind -- to bring together and assess the existing evidence examining the gendered association between unpaid labour and mental health.
Of the 14 studies included -- totalling more than 66,800 participants worldwide -- five examined unpaid labour (inclusive of care), nine examined housework time and, of these, four also examined childcare.
Researchers found that in addition to the economic penalty women experience shouldering most of the world's unpaid labour load, there is a mental health cost as well.
Overall, in 11 of the 14 studies examined, women self-reported increased depressive or psychological distress symptoms with increasing unpaid labour demands. For men, only three out of a possible 12 studies reported any negative association.
"We found substantial gender differences in exposure to unpaid labour, with women uniformly doing more in every geographical and time setting -- in more than 35 countries -- around the world," research lead Jen Ervin said.
"This double burden of paid and unpaid work exposures women to greater risk for overload, time poverty and poorer mental health. Crucially, women are also routinely trading off paid work hours to meet their disproportionally high unpaid labour responsibilities."
Ms Ervin said the study highlights the need for greater attention and meaningful action to drive greater equity in the division of unpaid labour.
"There is an undeniable mental load that accompanies unpaid labour and family responsibilities. Reducing the disproportionate unpaid labour burden on women, by enabling men to take on their equal share, has the potential to improve women's mental health," she said.
In addition, researchers say substantive policy changes, such as universal childcare and normalising flexible working arrangements for men are urgently required to enable real change.
Researchers conclude that this review highlights the need for further high-quality longitudinal research in this area, the need to better understand nuances within different dimensions of unpaid labour, as well as the need for a consistent approach in how unpaid labour is defined and measured.
https://www.sciencedaily.com/releases/2022/08/220831210017.htm
Babies born to older paternal cry differently, mouse pup study shows
August 23, 2022
Science Daily/Tohoku University
A baby's cry is a form of communication used to attract attention from adult caregivers, and every baby cries in a similar but distinct way. An international research team has studied the vocal behavior of baby mice, called pups, to determine how the age of the father affects the pups' vocal communication and body weight development. Their study will help them better understand vocal development in human babies.
The team published their findings in the journal iScience on August 10, 2022.
Research suggests that infant crying can serve as a marker of a baby's development. Altered crying in a baby may indicate a risk for autism spectrum disorder or other neurodevelopmental disorders. Researchers know that children with these disorders show particular crying patterns.
However, scientists do not fully understand what makes the crying patterns of these children different. Recent studies have shown that advanced paternal age is a risk factor for neurodevelopmental disorders and lower body weight in the offspring.
Wanting to better understand the connection between a father's age and vocal behavior in their offspring, a research team led by Professor Noriko Osumi, Tohoku University Graduate School of Medicine has conducted a study, using mice, to determine how paternal aging influences the vocal behavior of offspring.
One of the team's main findings was that the advanced paternal age causes alterations in early vocal behavior and increases the number of offspring with atypical developmental patterns. "This vocal feature of pups born to aged fathers is similar to that of pups from autism spectrum disorder model mice. Moreover, pups born to young fathers showed a rich repertoire, while those born to aged fathers exhibited a limited repertoire," said Professor Osumi.
In recent years, scientists have studied ultrasonic vocalizations in mice to learn more about the neurobiology of vocal communication. They know that when a pup is separated from its mother and littermates, it emits ultrasonic vocalizations consisting of various sound elements. When the mother hears these sounds, she responds by coming to retrieve the pup. This type of behavior in mice is similar to that of a human infant and mother.
The Tohoku University research team conducted a series of computational analyses of ultrasound vocalizations, comparing the pups of females who mated with young males and females who mated with older males. They separated the young pups from their mother and littermates, one by one, and recorded the ultrasonic vocalizations that occurred. Then the researchers analyzed the ultrasonic vocalization sonograms using machine learning tools.
The researchers examined the ultrasonic vocalization consisting of syllables. Their analyses showed that in pups with advanced age fathers, the syllables were reduced in number and duration. The syllable composition was also altered, with a more limited syllable repertoire in the pups with advanced age fathers. In addition, they measured the body weight of the pups after they completed each ultrasound vocalization recording. Comparing the weights, the team discovered that the pups with the advanced age fathers had consistently lower body weight gain than pups with young fathers.
In modern societies where humans are marrying and giving birth at older ages, advanced paternal age may represent a risk factor for neurodevelopmental disorders. This finding reiterates the clinical evidence that advanced paternal age is a risk factor for the atypical development observed in children with neurodevelopmental disorders and suggests that the effect of advanced paternal age could be detected in early infancy. As a next step, the team will be working to identify the neural basis governing ultrasound generation and the mechanisms by which advanced paternal age affects the offspring.
https://www.sciencedaily.com/releases/2022/08/220823162739.htm
Preterm birth's link with educational attainment explored in U.K. primary and secondary schoolchildren
Preterm children experience higher rates of poor school attainment, but only kids born very preterm remain at risk by the end of secondary school
August 17, 2022
Science Daily/PLOS
All children born before full term are more likely to have poorer attainment during primary school compared with children born full term (39-41 weeks), but only children born very preterm -- before 32 weeks -- remain at risk of poor attainment at the end of secondary schooling, according to a new study published this week in the open-access journal PLOS ONE by Neora Alterman, Maria Quigley of Oxford Population Health, U.K., and colleagues.
Preterm birth, defined as birth before 37 complete weeks of gestation, accounts for approximately 11% of births globally. Previous studies have shown that children born preterm are at higher risk of poorer academic attainment in primary school compared with children born at full term. However, few studies have followed these children through secondary school, or examined the full spectrum of gestational ages at birth.
In the new study, the researchers used data on children born in England from 2000-2001 who were surveyed in the population-based UK Millennium Cohort Study. Of 11,695 children in that sample, the authors analyzed data on attainment in primary school (at age 11) for 6,950 pupils, and information on secondary school attainment (at age 16) for 7,131 pupils.
At the end of primary school, 17.7% of children had not achieved the expected level in both English and Mathematics. Compared to full term children, children born before 32 weeks or at 32-33 weeks were more than twice as likely not to meet these benchmarks (adjusted relative risk; aRR=2.06, 95% CI 1.46-2.92; aRR=2.13, 95% CI 1.44-3.13). Children born late preterm, at 34-36 weeks, or early term, at 37-38 weeks, were at smaller increased risk of not achieving expected attainment (aRR=1.18, 95% CI 0.94-1.49; aRR=1.21, 95% CI 1.05-1.38).
At the end of secondary school, 45.2% of pupils had not passed at least five General Certificate of Secondary Education (GCSE) examinations including English and Mathematics. Following adjustment, children born very preterm, before 32 weeks, had a 26% elevated risk of not passing five GCSEs (aRR=1.26, 95% CI 1.03-1.54), with 60% of students in this group not achieving five GCSEs. However, children born at any gestation between 32 and 38 weeks were not at elevated risk compared to children born at full term. Further studies are needed in order to confirm this result.
The authors conclude that children born very preterm may benefit from screening for cognitive and language difficulties prior to school entry to guide the provision of additional support during schooling.
The authors add: "Our study showed that birth at any gestational age earlier than full term was associated with poorer attainment at the end of primary school. However, at the end of compulsory education, these pupils had similar outcomes to their peers, except for pupils born at less than 32 weeks, who remained at risk of low attainment."
https://www.sciencedaily.com/releases/2022/08/220817144026.htm
Deciphering a baby's cries of pain is not an innate ability and must be learned
August 8, 2022
Science Daily/Cell Press
Before young children learn to speak, crying is their only means of vocal communication. But do adults know when a baby is in pain as opposed to being mildly uncomfortable? A new study reported in Current Biology on August 8, 2022 finds that the answer to this question is that it depends.
"We found that the ability to detect pain in cries -- that is, to identify a pain cry from a mere discomfort cry -- is modulated by experience of caring for babies," says Nicolas Mathevon, University of Saint-Etienne, France. "Current parents of young babies can identify a baby's pain cries even if they have never heard this baby before, whereas inexperienced individuals are typically unable to do so."
The findings show that humans' ability to interpret babies' cries isn't innate but learned from experience. Parenting young babies shapes our ability to decode the information conveyed by babies' communication signals.
Mathevon and his University of Saint-Etienne colleagues including David Reby and Roland Peyron made this discovery as part of a broader research program investigating how information is encoded in babies' cries and how human listeners extract this information. In the new study, they wanted to find out how prior caregiving experience with babies shaped the ability to identify when they were in pain.
They recruited people with different amounts of experience caring for babies, ranging from people with no experience at all to current parents of young children. They also included people with occasional experience babysitting and non-parents with more extensive professional experience in caregiving.
Next, they gave everyone in the study a short training phase in which they heard eight discomfort cries from one baby over a couple of days. Next, their ability to decode the cries as discomfort or pain was put to the test.
And it turned out that experience was everything. People with little to no experience couldn't tell the difference between cries any better than chance. Those with a small amount of experience performed slightly better.
Current parents and professionals did better than chance. But parents of younger babies were the clear winners. They were able to identify the crying contexts of babies even when they'd never heard the cries of that youngster before. Parents of older kids and those with professional experience didn't do well with unfamiliar cries.
"Only parents of younger babies were also able to identify the crying contexts of an unknown baby they had never heard before," says first author of the study Siloe Corvin.
"Professional pediatric caregivers are less successful at extending this ability to unknown babies," says study co-author Camille Fauchon. "This was surprising at first, but it is consistent with the idea that experienced listeners may develop a resistance that decreases their sensitivity to acoustic cues of pain."
The findings show that babies' cries contain important information that's encoded in their acoustic structure. While adults are attuned to that information, our ability to decode it and identify when a baby is in pain gets better with exposure and experience.
The researchers hope that learning more about how babies communicate pain may help parents learn how to recognize and respond to it even better. They're now conducting neuroimaging studies to further explore how experience and parenthood shape brain activity when babies cry.
https://www.sciencedaily.com/releases/2022/08/220808161630.htm
Inflammatory bowel disease increases risks for pregnant women
Study of 8 million pregnancies shows greater likelihood of poor maternal and fetal outcomes
August 3, 2022
Science Daily/University of Missouri-Columbia
Pregnant women with inflammatory bowel disease (IBD) and their babies face increased risks and complications compared to pregnant women without IBD. Those are the findings from a new University of Missouri School of Medicine study that examined outcomes of more than 8 million pregnancies.
IBD is a term used for Crohn's disease and ulcerative colitis, which are characterized by chronic inflammation of the gastrointestinal tract. IBD mainly affects young people, which includes women who are in their peak reproductive years.
"IBD is an incurable disease, and its relapsing and remitting nature is stressful for the estimated 3 million U.S. men and women diagnosed," said senior author Yezaz Ghouri, MD, assistant professor of clinical medicine. "Because this disease tends to affect women during their peak fertility period, we wanted to know the impact of IBD on maternal and fetal outcomes. To our knowledge, this study is the most comprehensive of its kind, using data from multiple institutions in 48 states."
The research team reviewed more than 8 million pregnancies between 2016 and 2018. Of those, 14,129 mothers had IBD. Results showed the pregnant women with IBD had higher incidence of gestational diabetes, postpartum hemorrhage, hypertensive complications, preterm delivery, fetal growth restriction and fetal death. Pregnant women with IBD also had longer hospital stays after delivering. They averaged an additional half-day length of stay and faced more than $2,700 in associated medical costs.
"Based on our findings, we suggest that women who have moderate to severe IBD should get pre-conceptional counseling and be treated aggressively to achieve remission prior to getting pregnant," Ghouri said. "Our study results illustrate the importance that IBD be optimally controlled prior to conception."
https://www.sciencedaily.com/releases/2022/08/220803112620.htm
Women urged to eat potassium-rich foods to improve their heart health
July 21, 2022
Science Daily/European Society of Cardiology
Women who eat bananas, avocados and salmon could reduce the negative effects of salt in the diet, according to a study published today in European Heart Journal, a journal of the European Society of Cardiology (ESC).1 The study found that potassium-rich diets were associated with lower blood pressure, particularly in women with high salt intake.
"It is well known that high salt consumption is associated with elevated blood pressure and a raised risk of heart attacks and strokes," said study author Professor Liffert Vogt of Amsterdam University Medical Centers, the Netherlands. "Health advice has focused on limiting salt intake but this is difficult to achieve when our diets include processed foods. Potassium helps the body excrete more sodium in the urine. In our study, dietary potassium was linked with the greatest health gains in women."
The study included 24,963 participants (11,267 men and 13,696 women) of the EPIC-Norfolk study, which recruited 40 to 79 year olds from general practices in Norfolk, UK, between 1993 and 1997. The average age was 59 years for men and 58 years for women. Participants completed a questionnaire on lifestyle habits, blood pressure was measured, and a urine sample was collected. Urinary sodium and potassium were used to estimate dietary intake. Participants were divided into tertiles according to sodium intake (low/medium/high) and potassium intake (low/medium/high).
The researchers analysed the association between potassium intake and blood pressure after adjusting for age, sex and sodium intake. Potassium consumption (in grams per day) was associated with blood pressure in women -- as intake went up, blood pressure went down. When the association was analysed according to sodium intake (low/medium/high), the relationship between potassium and blood pressure was only observed in women with high sodium intake, where every 1 gram increase in daily potassium was associated with a 2.4 mmHg lower systolic blood pressure. In men, there was no association between potassium and blood pressure.
During a median follow-up of 19.5 years, 13,596 (55%) participants were hospitalised or died due to cardiovascular disease. The researchers analysed the association between potassium intake and cardiovascular events after adjusting for age, sex, body mass index, sodium intake, use of lipid lowering drugs, smoking, alcohol intake, diabetes and prior heart attack or stroke. In the overall cohort, people in the highest tertile of potassium intake had a 13% lower risk of cardiovascular events compared to those in the lowest tertile. When men and women were analysed separately, the corresponding risk reductions were 7% and 11%, respectively. The amount of salt in the diet did not influence the relationship between potassium and cardiovascular events in men or women.
Professor Vogt said: "The results suggest that potassium helps preserve heart health, but that women benefit more than men. The relationship between potassium and cardiovascular events was the same regardless of salt intake, suggesting that potassium has other ways of protecting the heart on top of increasing sodium excretion."
The World Health Organization recommends that adults consume at least 3.5 grams of potassium and less than 2 grams of sodium (5 grams of salt) per day.2 High potassium foods include vegetables, fruit, nuts, beans, dairy products and fish. For example, a 115 gram banana has 375 mg of potassium, 154 grams of cooked salmon has 780 mg, a 136 gram potato has 500 mg, and 1 cup of milk has 375 mg.
Professor Vogt concluded: "Our findings indicate that a heart healthy diet goes beyond limiting salt to boosting potassium content. Food companies can help by swapping standard sodium-based salt for a potassium salt alternative in processed foods. On top of that, we should all prioritise fresh, unprocessed foods since they are both rich in potassium and low in salt."
https://www.sciencedaily.com/releases/2022/07/220721204852.htm
Seven-month-old babies already have a sense of symmetry
August 8, 2022
Science Daily/University of the Basque Country
A collaborative study examined the spontaneous looking patterns of 7-month-old babies when presented with mosaic-like sequences with a symmetrical and asymmetrical structure. The results show that these babies quickly detect whether a mosaic has a symmetrical structure, suggesting a robust, automatic ability to extract structure from complex images.
The UPV/EHU's Gogo Elebiduna research group is a pioneer in the field of psycholinguistics; it conducts research of various kinds to obtain knowledge about how the language faculty is acquired, represented and organised in the brains of speakers, and about the nature of the universal characteristics of language representation and processing.
The group's Ikerbasque research fellow Irene de la Cruz-Pavía conducted a study in collaboration with the University of Padua researcher Judit Gervain and which was recently published in the journal PLOS ONE; it explores the ability of 7-month-old infants to perceive structural symmetry in abstract, mosaic-like visual patterns. This research was carried out at the University of Paris. "We examined the spontaneous looking patterns of almost 100 infants when presented with mosaic-like sequences displaying symmetrical and asymmetrical structures," the researchers explained.
These mosaics comprised two categories of square tiles (A and B) that differed in terms of their colour scheme and internal shape. These tiles were arranged to create mosaics with symmetrical (e.g. ABA, ABABA) or asymmetrical (e.g. AAB, AABBA) structures. The study found that the infants "discriminated between structurally symmetrical and asymmetrical mosaics, and that the length of the sequence (3 or 5 tiles) or the level of symmetry did not significantly modulate their behaviour." These results suggest that infants quickly detect structural symmetry in complex visual patterns: "Babies as young as 7 months have a robust, automatic ability to detect that a structure is symmetrical. This ability coincides with those found in studies we conducted using other stimuli, such as sign language or speech, demonstrating that babies are simply very good at detecting structures and regularities," said the researcher in the UPV/EHU's Department of Linguistics and Basque Studies.
Ability of babies to extract structure and rules from various media
As the Ikerbasque research fellow pointed out, "the grammar of a language consists of the set of structures and rules of a language. I want to understand to what extent infants' abilities to extract structures, detect regularities and learn rules are specific to language or whether they are found in other areas." "We conducted this study using information that is visual but which is not language. With these mosaics, we were able to see how babies were capable of extracting structure from different media."
The researchers stress that this study allows them to better understand "these infants' fundamental skills, which will enable them to start initially with some of the more accessible parts of grammar and gradually build up to something as complex as the grammar of a language. What we want to understand is this: what are the fundamental abilities of babies when it comes to detecting structure?"
"We have many more questions to answer," they concluded. "In this study we were able to determine that babies are able to detect structures spontaneously and quickly. Now we want to understand when this ability begins, and the degree of detail with which they analyse that structure and what aspects of the mosaics allow them to detect its structure (the shape, the colour, both...)."
https://www.sciencedaily.com/releases/2022/08/220808162226.htm
Moms' problems linked to adolescent attachment issues
Mothers' own experiences with caregivers may be important driver within this relationship
August 9, 2022
Science Daily/University of Houston
Psychology research finds that moms with personality disorder symptoms impact their adolescent children who subsequently show a higher likelihood of insecure attachment which can impact their socio-emotional development and mental health.
It should come as no great surprise that mothers have profound influence on their children. But what about mothers who have their own personality disorder symptoms, such as problems getting along with others? New research finds, for the first time, that maternal personality disorder symptoms impact their adolescent children who subsequently show a higher likelihood of insecure attachment.
Secure attachment is the goal -- it is when children feel comforted by the presence of their parent of caregiver and is a significant factor for socio-emotional development and mental health in youth. Previous research has shown that insecure attachment is associated with depression and anxiety, delinquency and substance use problems, and poorer social competence in children.
"When mothers struggle in their own interpersonal relationships, the passing on of secure attachment and healthy relationship functioning to adolescent offspring seem to be impeded," reports Carla Sharp, professor of psychology and director of the University of Houston Developmental Psychopathology Lab, in the journal Borderline Personality Disorder and Emotion Dysregulation. "Maternal interpersonal problems were associated with higher levels of insecure attachment in adolescent offspring such that adolescents would either dismiss the need for attachment with their moms or show angry preoccupation with the relationship with their moms."
While mothers' problems have long been shown to be associated with maladaptive adult attachment in close or romantic relationships, this is the first study to examine relationships with offspring attachment. The research could inform interventions to prevent or reduce youth psychopathology and other negative outcomes.
Parent-child attachment security continues to play an important role through adolescence, which is thought to be the second most critical developmental window after infancy and early childhood.
Sharp and team interviewed 351 psychiatric inpatient adolescents (average age of 15 and 64% female) and their biological mothers. Participants were asked about distressing interpersonal behaviors that they find "hard to do" (e.g., "It is hard for me to feel close to other people") or "do too much" (e.g., "I try to please other people too much"). Children were assessed on their ability to describe their attachment experiences coherently and collaboratively and to reflect on these experiences and their impact on them.
The team also examined whether mothers' recalled bonding with their own mothers to explain the relationship with their children. It did.
"The way that parents recalled their experiences with their caregivers is likely impacted by their own interpersonal functioning and may impact the relationship that they build with their children," said Sophie Kerr, first author of the article and graduate student of Sharp's.
Those results will drive researchers to further examine mechanisms of intergenerational risk to tailor interventions aimed to improve parent-child relations and attachment.
"Findings highlight the mediating role of the mothers' recalled experiences with caregivers in the impact of their interpersonal problems on adolescents, suggesting interventions that enhance interpersonal function such as mentalization-based interventions may be helpful for mothers with interpersonal problems and personality pathology," said Sharp.
https://www.sciencedaily.com/releases/2022/08/220809141259.htm
Link between air pollution and child brain development strengthened
July 14, 2022
Science Daily/University of Washington
Air pollution is not just a problem for lungs. Increasingly, research suggests air pollution can influence childhood behavioral problems and even IQ. A new study led by the University of Washington has added evidence showing that both prenatal and postnatal exposure to air pollution can harm kids.
The study, published in Environmental Health Perspectives, found that children whose mothers experienced higher nitrogen dioxide (NO2) exposure during pregnancy, particularly in the first and second trimester, were more likely to have behavioral problems.
Researchers also reported that higher exposures to small-particle air pollution (PM2.5) when children were 2 to 4 years old was associated with poorer child behavioral functioning and cognitive performance.
"Even in cities like Seattle or San Francisco, which have a lot of traffic but where the pollution levels are still relatively low, we found that children with higher prenatal NO2 exposure had more behavioral problems, especially with NO2exposure in the first and second trimester," said Yu Ni, lead author and a postdoctoral scholar in the Department of Environmental & Occupational Health Sciences.
The study involved data gathered from 1,967 mothers recruited during pregnancy from six cities: Memphis, Tennessee; Minneapolis; Rochester, N.Y.; San Francisco; and two in Washington, Seattle and Yakima. Originally, these participants were enrolled as part of three separate studies: CANDLE, GAPPS and TIDES. The three studies have been combined under a major NIH initiative called ECHO, which brings together multiple pregnancy cohorts to address key child health concerns. These three combined cohorts are known as the ECHO PATHWAYS consortium.
The study employed a state-of-the-art model of air pollution levels in the United States over time and space that was developed at the University of Washington. Using participant address information, the researchers were able to estimate each mother and child's exposures during the pregnancy period and early childhood.
Exposure to NO2 and PM2.5 pollution in early life is important to understand, Ni said, because "there are known biological mechanisms that can link a mother's inhalation of these pollutants to effects on placenta and fetal brain development."
Furthermore, once the child is born, the first few years are a critical time of ongoing brain development as the number of neural connections explodes and the brain reaches 90% of its future adult size, the researchers write. For young children, inhaled pollutants that invade deep in the lung and enter the central nervous system can cause damage in areas relevant for behavioral and cognitive function.
"This study reinforces the unique vulnerability of children to air pollution -- both in fetal life where major organ development and function occurs as well as into childhood when those processes continue. These early life perturbations can have lasting impacts on lifelong brain function. This study underscores the importance of air pollution as a preventable risk factor for healthy child neurodevelopment," said senior author Dr. Catherine Karr, a professor in the UW School of Public Health and School of Medicine.
More specifically, the researchers found that exposure to PM2.5pollution was generally associated with more behavioral problems in girls than in boys, and that the adverse effect of PM2.5 exposure in the second trimester on IQ was stronger in boys.
"We hope the evidence from this study will contribute to informed policymaking in the future," Ni said. "In terms of reducing air pollution, the U.S. has gone a long way under the Clean Air Act, but there are threats to continued improvement in the nation's air quality. The evidence suggests there is reason to bring the level of air pollution down even further as we better understand the vulnerability of pregnant women and children."
Co-authors include Christine Loftus, Michael Young and Marnie Hazlehurst, UW Department of Environmental and Occupational Health Sciences; Sheela Sathyanarayana, UW School of Public Health and School of Medicine; Adam Szpiro, UW Department of Biostatistics; Laura Murphy, Frances Tylavsky and W. Alex Mason, University of Tennessee; Kaja LeWinn and Nicole Bush, University of California San Francisco; and Emily Barrett, Rutgers University. This research was funded by the National Institutes of Health through the ECHO-PATHWAYS consortium.
https://www.sciencedaily.com/releases/2022/07/220714145232.htm
Scientists pinpoint reason why women may not respond to depression treatments the same as men
July 13, 2022
Science Daily/University of California - Davis
Although treatments for depression exist, sometimes these treatments don't work for many who use them. Furthermore, women experience higher rates of depression than men, yet the cause for this difference is unknown, making their illnesses, at times, more complicated to treat.
University of California, Davis, researchers teamed up with scientists from Mt. Sinai Hospital, Princeton University, and Laval University, Quebec, to try to understand how a specific part of the brain, the nucleus accumbens, is affected during depression. The nucleus accumbens is important for motivation, response to rewarding experiences and social interactions -- all of which are affected by depression.
Previous analyses within the nucleus accumbens showed that different genes were turned on or off in women, but not in men diagnosed with depression. These changes could have caused symptoms of depression, or alternatively, the experience of being depressed could have changed the brain. To differentiate between these possibilities, the researchers studied mice that had experienced negative social interactions, which induce stronger depression-related behavior in females than males.
"These high-throughput analyses are very informative for understanding long-lasting effects of stress on the brain. In our rodent model, negative social interactions changed gene expression patterns in female mice that mirrored patterns observed in women with depression," said Alexia Williams, a doctoral researcher and recent UC Davis graduate who designed and led these studies. "This is exciting because women are understudied in this field, and this finding allowed me to focus my attention on the relevance of these data for women's health."
The study "Comparative transcriptional analyses in the nucleus accumbens identifies RGS2 as a key mediator of depression-related behavior," was published this month in the journal Biological Psychiatry.
After identifying similar molecular changes in the brains of mice and humans, researchers chose one gene, regulator of g protein signaling-2, or Rgs2, to manipulate. This gene controls the expression of a protein that regulates neurotransmitter receptors that are targeted by antidepressant medications such as Prozac and Zoloft. "In humans, less stable versions of the Rgs2 protein are associated with increased risk of depression, so we were curious to see whether increasing Rgs2 in the nucleus accumbens could reduce depression-related behaviors," said Brian Trainor, UC Davis professor of psychology and senior author on the study. He is also an affiliated faculty member with the Center for Neuroscience and directs the Behavioral Neuroendocrinology Lab at UC Davis.
When the researchers experimentally increased Rgs2 protein in the nucleus accumbens of the mice, they effectively reversed the effects of stress on these female mice, noting that social approach and preferences for preferred foods increased to levels observed in females that did not experience any stress.
"These results highlight a molecular mechanism contributing to the lack of motivation often observed in depressed patients. Reduced function of proteins like Rgs2 may contribute to symptoms that are difficult to treat in those struggling with mental illnesses," Williams said.
Findings from basic science studies such as this one may guide the development of pharmacotherapies to effectively treat individuals suffering from depression, the researchers said.
"Our hope is that by doing studies such as these, which focus on elucidating mechanisms of specific symptoms of complex mental illnesses, we will bring science one step closer to developing new treatments for those in need," said Williams.
https://www.sciencedaily.com/releases/2022/07/220713154246.htm