Patricia Adams

Living Abroad Tied to Clearer Sense of Self

A new study reveals that living abroad can help clarify one’s sense of self. According to the findings, living in other parts of the world encourages us to reflect on the various cultural values and norms that we encounter both at home and in the host cultures.

In turn, these reflections can help us discover which values define us personally and which simply reflect our cultural upbringing. This is particularly true for those who live abroad for a long period of time.

The research was conducted by a team of social scientists from Rice University, Columbia University and the University of North Carolina. Their paper is published in the journal Organizational Behavior and Human Decision Processes.

Previous research has shown that transitional experiences, such as getting divorced or losing a job, typically decrease individuals’ self-concept clarity. In contrast, this study looks at the possibility that living abroad is a rare kind of transitional experience that actually increases self-concept clarity.

“In a world where living-abroad experiences are increasingly common and technological advances make cross-cultural travel and communication ever easier, it is critical that research keeps pace with these developments and seeks to understand how they affect people,” the authors wrote.

“In this vein, our studies demonstrate that living abroad affects the fundamental structure of the self-concept by enhancing its clarity. The German philosopher Hermann von Keyserling wrote in the epigraph to his 1919 book ‘The Travel Diary of a Philosopher,’ ‘The shortest path to oneself leads around the world.’ Almost 100 years later, our research provides empirical evidence in support of this idea.”

The researchers conducted six studies involving 1,874 participants who were recruited from online panels as well as from U.S. and international MBA programs. The participants, including those who have and have not lived abroad, completed surveys.

Most research on foreign experiences has focused on whether people have lived abroad or not, but this new study takes a more nuanced approach to distinguish between the depth and the breadth of international experiences. The findings suggest that depth (the length of time lived abroad) rather than breadth (the number of foreign countries lived in) enhances a clear sense of self.

The authors found that the longer people live abroad, the more self-discerning reflections they accumulate. As a result, they are more likely to develop a better understanding of themselves and show increased clarity about career decision-making, the authors said.

Understanding the impact of living abroad has practical implications for organizations as they operate across national borders and recruit foreign talent.

Extended periods of time spent in a foreign country can yield a myriad of benefits, including greater life satisfaction, decreased stress, improved job performance and enhanced clarity regarding a fulfilling career. Having a clearer sense of self is increasingly important in today’s world with its unprecedented range of available career options, according to the authors.

Source: Rice University

 

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Family Behavioral Therapy for Obesity May Work Best for Impulsive Kids

Although impulsivity may increase the risk for obesity in children, the trait appears to be linked to better outcomes during family-based behavioral treatment (FBT) for weight loss.

FBT is designed to change parent and child behaviors and is currently the recommended intervention for children with obesity. The new study was presented, at ENDO 2018, the 100th annual meeting of the Endocrine Society in Chicago, Ill.

“Our novel results indicate that impulsivity may be a risk factor for uncontrolled eating and excessive weight gain,” said lead study author Christian L. Roth, M.D., professor of pediatrics at the Seattle Children’s Research Institute in Washington.

“Children who rated high in impulsivity had higher body mass index (BMI) measures and greater body fat mass compared to those who rated lower in impulsivity.”

“However, we found that children with obesity who were rated as more impulsive prior to starting FBT had greater weight-loss success in the program compared to children with obesity who were rated as less impulsive,” added co-author Kelley Scholz, M.S.W., research supervisor at Seattle Children’s Research Institute.

Researchers assessed the impact of a six-month long FBT obesity intervention delivered to 54 children with obesity and 22 healthy-weight children, all between 9 and 11 years of age.

The authors rated the children for impulsivity using attention and inhibition tasks from a standardized test — the Developmental NEuroPSYchological Assessment — NEPSY-II.

The healthy-weight children did not take part in the FBT program but were tested at the beginning and end of the study along with the participants who had obesity.

At baseline, a larger proportion of children with obesity scored as high-impulsivity compared with healthy-weight children. Among children with obesity, those who scored high in impulsivity had higher BMI and greater fat mass.

The children with obesity and their families took part in 24 weekly FBT session that involved a meeting between the family and a staff member in a private room for about 30 minutes with discussion of issues specifically related to that family. Also, 45-minute parent and child group sessions were held in a large conference room.

Therapy meetings focused on food, physical activity education and behavioral skills such as self-monitoring and environmental control, using praise and rewards to reinforce positive eating and physical activity.

The NEPSY-II inhibition test results predicted weight loss. Of the 40 children with obesity who completed the study, the 18 who were rated high-impulsivity had a greater drop in BMI than the lower-impulsivity obese children.

Inhibition scores improved at the end of the FBT program, and the children whose inhibition scores improved most had greater drops in BMI and fat mass.

Although the results look promising, the researchers recommend further related research.

Source: The Endocrine Society/EurekAlert

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Kids’ Personality Traits Tied to Later Political Leanings

Kids’ Personality Traits Tied to Later Political Leanings

New research finds that adults’ political tendencies can be traced back to early childhood temperament, those aspects of personality that are thought to be biologically based, or innate, rather than learned.

Researchers in the U.K. looked at data from more than 16,000 participants in two longitudinal studies. Their analysis revealed links between conduct problems at ages 5 and 7 and economic and political discontent 25 years later.

The findings are published in Psychological Science, a journal of the Association for Psychological Science.

“Findings from both studies indicate that children who showed higher levels of conduct problems – that is, aggression, fighting, stealing from peers – were more likely to be economically left-leaning and distrustful of the political system as adults,” said study author Dr. Gary J. Lewis of Royal Holloway, University of London. “Some, but not all, of this link was explained by educational attainment and socioeconomic status in adulthood.”

The findings shed light on the relationship between personality traits and political sentiment, suggesting a link that spans more than two decades.

Lewis investigated this link by analyzing data from the British Cohort Study and the National Child Development Study, two longitudinal cohort studies following individuals in the United Kingdom.

Participants’ parents completed an assessment of their children’s behavior when the children were either 5 or 7 years old, reporting on behaviors related to anxiety, conduct problems and hyperactivity.

At age 30 or 33, the participants completed measures that gauged their economic conservatism, political cynicism, racism, authoritarianism and attitudes about gender inequality. These measures cohered into two broad factors: economic/political discontent and social conservatism.

The studies also included data about the parents’ social class and the participants’ childhood intelligence, educational attainment and social class in adulthood.

Modeling the relationships among these variables, Lewis found that childhood conduct problems were associated with economic/political discontent in adulthood, even after parental social class and childhood intelligence were taken into account. It is possible, Lewis noted, that conduct problems in childhood may reflect difficulty with self-control and long-term planning or early rejection of authority, either of which could lead to economic/political discontent.

The models also indicated indirect pathways in both cohorts, by which conduct problems were associated with lower educational attainment and adult social class and, ultimately, greater economic/political discontent.

These associations may be modest in strength, said Lewis, but they are stable over a 25-year span, suggesting early foundations of later political attitudes. Future research with more detailed and frequent assessments will help to illuminate the exact nature of these long-term associations.

“We all wonder from time to time why it is that those on the other side of the fence came to be that way,” Lewis said. “These findings take us a little further down the road to answering that question.”

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Study Finds Delay in Initial Dementia Diagnosis

Study Finds Delay in Initial Dementia Diagnosis

A new study has found that dementia patients are not undergoing evaluation at the onset of the dementia process, a delay that prevents early, beneficial treatment.

The study, conducted by a multidisciplinary Spectrum Health neurology team, also found that home-based, patient-centered care may improve early screening and detection of dementia.

For the new study, researchers reviewed 110 randomly-chosen initial evaluations from the Spectrum Health Medical Group Neurocognitive Clinic in Grand Rapids, Michigan, from 2008 to 2015.

They discovered that 78.9 percent of the patients evaluated already had moderate or severe dementia at the time of diagnosis.

“The findings indicate that people are living with dementia for significant periods of time before seeking diagnosis and treatment,” said Timothy Thoits, M.D., lead author and neurology division chief, Spectrum Health Medical Group. “The earlier the diagnosis, the earlier treatment can begin and the earlier the benefit to the patient and his or her family and caregivers.”

The researchers reviewed the initial diagnostic patient evaluations, which included a neurological examination, Montreal Cognitive Assessment, and a battery of neuropsychological testing. They determined dementia stage and severity by correlating it with the number of lifestyle changes recommended at the time of diagnosis, which they say is a novel study method that has not previously been used.

Lifestyle changes included medication assistance, financial assistance, driving restrictions, and institutional care. At the time of diagnosis, providers recommended lifestyle changes in 75.8 percent of patients with dementia.

The study concludes that “an increase in home-based, patient-centered medical care, regardless of the patient’s living status, may be one way to improve recognition of cognitive deficits and increase the frequency of important and necessary early cognitive evaluations.”

The World Health Organization (WHO) defines home-based care as “any form of assistance provided to a sick person referred to as the patient directly in the home by family, friends, and members of the local community, cooperating with the advice and support from the trained health workers.”

The study was published in The American Journal of Alzheimer’s Disease & Other Dementias.

Source: Spectrum Health

Photo: Timothy Thoits, M.D., lead author and neurology division chief, Spectrum Health Medical Group. Credit: Spectrum Health.

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New Clues on Why Sense of Direction Fades With Age

New Clues on Why Sense of Direction Fades With Age

A new study has found a possible explanation for the difficulty in spatial orientation sometimes experienced by elderly people.

During the study, researchers detected unstable activity in the brains of older adults in an area that is central for spatial navigation.

In the long term, these findings might open up new ways for detecting Alzheimer’s disease, according to researchers at the German Center for Neurodegenerative Diseases (DZNE).

To guide us through space in a goal-directed manner, the brain has to process a flood of information, ranging from visual stimuli to cues provided by the muscular system and our sense of balance. This means spatial orientation and navigation are among the most complex abilities of the human mind, researchers note.

Unfortunately, these skills often deteriorate as we grow older, which can severely compromise independence and quality of life.

“When you move around an unfamiliar environment, it is perfectly normal to get lost. Yet, this tends to happen more often to older people. So far, we know very little about the underlying neuronal mechanisms of these navigation problems,” said Matthias Stangl, a researcher at the DZNE’s Magdeburg site and first author of the study.

“We had the hypothesis that so-called grid cells might be implicated. A major part of the navigational processing is done by these cells. They are specialized neurons located in the brain’s entorhinal cortex. Therefore, we guessed that deficits in grid cell function might be a cause for problems in navigation.”

To test this assumption, Stangl and his colleagues performed experiments with 41 healthy young and older adults, who were split in two groups. The group of “young adults” consisted of 20 participants between the ages of 19 and 30, while the group of older adults was made up of 21 individuals between the ages of 63 and 81. Both groups included men and women.

One of the experiments combined functional brain imaging (fMRI) and virtual reality, according to the researchers. Participants had to navigate through a computer-generated scenery while their brain activity patterns were monitored.

A second experiment tested the ability for “path integration.” In this experiment, participants moved along predefined curved paths. At intermediate stops, they had to estimate their distance and orientation relative to their starting point, but without being able to see or pinpoint its location. Since this test was carried out in two versions, it took place both in real space and in a virtual environment, researchers explained.

“All things considered, young participants did better in navigation, which is in line with previous studies. However, we found an association between decreased navigational performance and deficits in grid cell activity,” said Professor Thomas Wolbers, a DZNE senior scientist and supervisor of the study.

“Grid cells fired differently when comparing young and old adults. Specifically, firing patterns were less stable over time in older individuals, which indicates that these brain circuits are compromised in old age. This might be a cause of why many senior people tend to have troubles with spatial navigation.”

“Grid cells play a central role not just in navigation but also in other cognitive functions,” Wolbers added. “Therefore, our findings might indicate a key mechanism underlying cognitive deficits in old age. Not only does this provide insights into neurophysiological changes due to aging, it may also help in designing therapies against age-related cognitive decline.”

While weakening navigational skills might occur in healthy adults, such a decline is also considered as one of the earliest symptoms of Alzheimer’s.

“Assessing navigation performance and grid cell function could possibly facilitate early diagnosis of Alzheimer’s and other neurodegenerative disorders,” Wolbers said.

“To this end, it would be necessary to develop diagnostic methods that distinguish between an age-related decline in navigational ability and a decline caused by disease. This might be a challenging task. However, our findings lay the foundation for future studies on such topics.”

The study was published in the journal Current Biology.

Source: German Center for Neurodegenerative Diseases

 
Photo: Soil patterns, as used in one of the experiments: a virtual, computer-generated scene was used to test the ability of young and older adults to orient themselves spatially. Credited to DZNE.

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Childhood Aggression Linked to Deficits in Executive Function

Childhood Aggression Linked to Deficits in Executive Function

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

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Ketamine Nasal Spray for Depression Runs Into Problems

Ketamine Nasal Spray for Depression Runs Into Problems

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

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Structural Brain Differences for Transgender People

Structural Brain Differences for Transgender People

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

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Nightmares Relatively Common Among Military Personnel

Nightmares Relatively Common Among Military Personnel

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

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ADHD Meds May Improve Mood in Healthy Humans

ADHD Meds May Improve Mood in Healthy Humans

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

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