Posts tagged adolescents
Articles and news from the latest research reports.
Caffeine affects boys and girls differently after puberty
Caffeine intake by children and adolescents has been rising for decades, due in large part to the popularity of caffeinated sodas and energy drinks, which now are marketed to children as young as four. Despite this, there is little research on the effects of caffeine on young people.
One researcher who is conducting such investigations is Jennifer Temple, PhD, associate professor in the Department of Exercise and Nutrition Sciences, University at Buffalo School of Public Health and Health Professions.
Her new study finds that after puberty, boys and girls experience different heart rate and blood pressure changes after consuming caffeine. Girls also experience some differences in caffeine effect during their menstrual cycles.
The study, “Cardiovascular Responses to Caffeine by Gender and Pubertal Stage,” will be published online June 16 in the July 2014 edition of the journal Pediatrics.
Past studies, including those by this research team, have shown that caffeine increases blood pressure and decreases heart rate in children, teens and adults, including pre-adolescent boys and girls. The purpose here was to learn whether gender differences in cardiovascular responses to caffeine emerge after puberty and if those responses differ across phases of the menstrual cycle.
Temple says, “We found an interaction between gender and caffeine dose, with boys having a greater response to caffeine than girls, as well as interactions between pubertal phase, gender and caffeine dose, with gender differences present in post-pubertal, but not in pre-pubertal, participants.
“Finally,” she says, “we found differences in responses to caffeine across the menstrual cycle in post-pubertal girls, with decreases in heart rate that were greater in the mid-luteal phase and blood pressure increases that were greater in the mid-follicular phase of the menstrual cycle.
“In this study, we were looking exclusively into the physical results of caffeine ingestion,” she says.
Phases of the menstrual cycle, marked by changing levels of hormones, are the follicular phase, which begins on the first day of menstruation and ends with ovulation, and the luteal phase, which follows ovulation and is marked by significantly higher levels of progesterone than the previous phase.
Future research in this area will determine the extent to which gender differences are mediated by physiological factors such as steroid hormone level or by differences in patterns of caffeine use, caffeine use by peers or more autonomy and control over beverage purchases, Temple says.
This double-blind, placebo-controlled, dose-response study was funded by a grant from the National Institute on Drug Abuse of the National Institutes of Health.
It examined heart rate and blood pressure before and after administration of placebo and two doses of caffeine (1 and 2 mg/kg) in pre-pubertal (8- to 9-year-old; n = 52) and post-pubertal (15- to 17-year-old; n = 49) boys (n = 54) and girls (n = 47).
Depression top cause of illness in world’s teens, WHO report
Depression is the top global cause of illness and disability for adolescents, with suicide the third-biggest cause of death, the World Health Organization said on Wednesday.
The finding is in a new report by the UN agency, which has pulled together a wealth of published evidence with direct consultations with 10 to 19-year-olds around the world to assess the health issues that affect them.
“The world has not paid enough attention to the health of adolescents,” says Flavia Bustreo, head of the WHO’s family, women and children’s health division.
Brain development provides insights into adolescent depression
Lead research Professor Nick Allen from the Melbourne School of Psychological Sciences said, “It is well known that the brain continues to change and remodel itself during adolescence as part of healthy development.”
“In this study, we found that the pattern of development (such as changes in brain structure between ages twelve to sixteen) in several key brain regions differed between depressed and non-depressed adolescents,” Professor Allen said.
The brain regions involved include areas associated with the experience and regulation of emotion, as well as areas associated with learning and memory.
“The findings are an important breakthrough for exploring possible causes of depression in adolescence. They also suggest that both prevention and treatment for depression (even for early signs and symptoms of depression) in adolescence is essential, especially targeting those in the early years of adolescence aged twelve to sixteen,” he said.
“We also observed some differences between males and females. For males, less growth in an area of the brain involved in processing threat and other unexpected events that is a critical part of the brain’s fear circuitry, was associated with depression. On the other hand, for females, greater growth of this area was found to be associated with depression.”
“This is important information because depression becomes much more common amongst girls during adolescence, and these findings tell us about some of the neurobiological factors that might play a role in this gender difference,” he said.
Professor Allen says adolescence is a period during the lifespan where risk for developing depression dramatically increases.
The study examined eighty-six adolescents (41 female) with no history of depressive disorders before age 12 by using a Magnetic Resonance Imaging (MRI) scanner, which allowed researchers to measure the volume of particular brain regions of interest. Participants underwent an MRI scan first at age twelve and again at age sixteen, when rates of depression were beginning to increase. Researchers also conducted detailed interviews with each of the participants at four different time points between age twelve and age eighteen. Thirty participants experienced a first episode of a depressive disorder during the follow-up period.
These findings have recently been published in the American Journal of Psychiatry.
Prolonged Exposure Therapy Found Beneficial in Treating Adolescent Girls with PTSD
Researchers at Penn Medicine report in the December 25 issue of JAMA that a modified form of prolonged exposure therapy – in which patients revisit and recount aloud their trauma-related thoughts, feelings and situations – shows greater success than supportive counseling for treating adolescent PTSD patients who have been sexually abused.
Despite a high prevalence of posttraumatic stress disorder (PTSD) in adolescents, evidence-based treatments like prolonged exposure therapy for PTSD in this population have never been established.
“We hypothesized that prolonged exposure therapy could fill this gap and were eager to test its ability to provide benefit for adolescent patients,” says Edna Foa, PhD, professor of Clinical Psychology in the department of Psychiatry in the Perelman School of Medicine at the University of Pennsylvania, who developed prolonged exposure therapy.
The concern has been that prolonged exposure therapy, while the most established evidence-based treatment for adults with PTSD, could exacerbate PTSD symptoms in adolescent patients who have not mastered the coping skills necessary for this type of exposure to be safely provided.
Adolescence is often a time when children begin to test limits and are in and out of situations, both good and bad – situations that often determine the path their lives take into adulthood.
The six-year (2006-2012) study examined the benefit of a prolonged exposure program called prolonged exposure-A (PE-A), that was modified to meet the developmental stage of adolescents, and compared it with supportive counseling in 61 adolescent girls, ages 13-18, with sexual abuse-related PTSD. In the single-blind randomized clinical trial, 31 received prolonged exposure-A, and 30 got supportive counseling.
Each received 14 60- to- 90 minute sessions of either therapy in a community mental health setting. The counselors were familiar with supportive counseling but naïve to PE-A before the study; their PE-A training consisted of a 4-day workshop followed by supervision every second week.
Outcomes were assessed before treatment, mid-treatment and after treatment and at three, six and 12-month follow up. During treatment, patients receiving PE-A demonstrated greater decline in PTSD and depression symptom severity, and improvement in overall functioning. These differences were maintained throughout the 12-month follow up period.
“Another key finding of this research was that prolonged therapy can be administered in a community setting by professionals with no prior training in evidence-based treatments and can have a positive impact on this population,” Foa says.
(Source: uphs.upenn.edu)
Brain size may signal risk of developing an eating disorder
New research indicates that teens with anorexia nervosa have bigger brains than teens that do not have the eating disorder. That is according to a study by researchers at the University of Colorado’s School of Medicine that examined a group of adolescents with anorexia nervosa and a group without. They found that girls with anorexia nervosa had a larger insula, a part of the brain that is active when we taste food, and a larger orbitofrontal cortex, a part of the brain that tells a person when to stop eating.
Guido Frank, MD, assistant professor of psychiatry and neuroscience at CU School of Medicine, and his colleagues report that the bigger brain may be the reason people with anorexia are able to starve themselves. Similar results in children with anorexia nervosa and in adults who had recovered from the disease, raise the possibility that insula and orbitofrontal cortex brain size could predispose a person to develop eating disorders.
"While eating disorders are often triggered by the environment, there are most likely biological mechanisms that have to come together for an individual to develop an eating disorder such as anorexia nervosa," Frank says.
The researchers recruited 19 adolescent girls with anorexia nervosa and 22 in a control group and used magnetic resonance imaging (MRI) to study brain volumes. Individuals with anorexia nervosa showed greater left orbitofrontal, right insular, and bilateral temporal cortex gray matter compared to the control group. In individuals with anorexia nervosa, orbitofrontal gray matter volume related negatively with sweet tastes. An additional comparison of this study group with adults with anorexia nervosa and a healthy control group supported greater orbitofrontal cortex and insula volumes in the disorder across this age group as well.
The medial orbitofrontal cortex has been associated with signaling when we feel satiated by a certain type of food (so called “sensory specific satiety”). This study suggests that larger volume in this brain area could be a trait across eating disorders that promotes these individuals to stop eating faster than in healthy individuals, before eating enough.
The right insula is a region that processes taste, as well as integrates body perception and this could contribute to the perception of being fat despite being underweight.
This study is complementary to another that found adults with anorexia and individuals who had recovered from this illness also had differences in brain size, previously published in the American Journal of Psychiatry.
(Source: eurekalert.org)
Food commercials excite teen brains
Watching TV commercials of people munching on hot, crispy French fries or sugar-laden cereal resonates more with teens than advertisements about cell phone plans or the latest car.
A new University of Michigan study found that regardless of body weight, teens had high brain activity during food commercials compared to nonfood commercials.
"It appears that food advertising is better at getting into the mind and memory of kids," said Ashley Gearhardt, U-M assistant professor of psychology and the study’s lead author. "This makes sense because our brains are hard-wired to get excited in response to delicious foods."
Children see thousands of commercials each year designed to increase their desire for foods high in sugar, fat and salt. Researchers from U-M, the Oregon Research Institute and Yale University analyzed how the advertising onslaught affects the brain.
Thirty teenagers (ages 14-17) ranging from normal weight to obese watched a television show with commercial breaks. Their brain activity was measured with a functional magnetic resonance imaging scanner.
The video showed 20 food commercials and 20 nonfood commercials featuring major brands such as McDonald’s, Cheerios, AT&T and Allstate Insurance. Study participants were asked to list five commercials they saw and to rate how much they liked the product or company featured in the ads.
Regions of the brain linked to attention, reward and taste were active for all participants, especially when food commercials aired. Overall, they recalled and liked food commercials better than nonfood commercials.
Teens whose weight was considered normal had greater reward-related brain activity when viewing the food commercials compared to obese adolescents. Gearhardt said this suggests that all teenagers, even those who are not currently overweight, are affected by food advertising and that exposure could lead to future weight gain in normal weight youth.
The study concluded that obese participants may attempt to control their response to food commercials, which might alter the way their brain responds. But if these teens are bombarded with frequent food cues, their self-control might falter—especially if they feel stressed, hungry or depressed.
Gearhardt said brain regions that are more responsive in lean adolescents during food commercials have been linked with future weight gain. These findings, which appear in the current issue of Social Cognitive and Affective Neuroscience, may inform the current debates about the impact of food advertising on minors.
Scientists identify depression and anxiety biomarker in youths
Scientists have discovered a cognitive biomarker – a biological indicator of a disease – for young adolescents who are at high risk of developing depression and anxiety. Their findings were published in the journal PLOS ONE.
The test for the unique cognitive biomarker, which can be done on a computer, could be used as an inexpensive tool to screen adolescents for common emotional mental illnesses. As the cognitive biomarker may appear prior to the symptoms of depression and anxiety, early intervention (which has proven to be one of the most effective ways of combatting mental illness) could then be initiated.
For the study, 15-18 year old participants underwent genetic testing and environmental assessment, an exercise which would currently be too expensive and take too long to use as a widespread method of screening. The adolescents were then given a computer test to gauge how they process emotional information. The test had the participants evaluate whether words were positive, negative or neutral (examples included ‘joyful’ for positive, ‘failure’ for negative, and ‘range’ for neutral).
Those adolescents with a variation of one gene (the short form of the serotonin transporter) as well as exposure to intermittent family arguments for longer than six months and violence between parents before the age of six were shown to have marked difficulty in evaluating the emotion within the words, indicating an inability to process emotional information. Previous research associated a maladjusted perception and response to emotions, as seen here, with a significantly increased risk of depression and anxiety.
Professor Ian Goodyer, Principal Investigator on the study from the University of Cambridge, said: “Whether we succumb to anxiety and depression depends in part on our tendencies to think well or poorly of ourselves at troubled times. How it comes about that some people see the ‘glass half full’ and think positively whereas other see the ‘glass half empty’ and think negatively about themselves at times of stress is not known.
The evidence is that both our genes and our early childhood experiences contribute to such personal thinking styles. Before there are any clinical symptoms of depression or anxiety, this test reveals a deficient ability to efficiently and effectively perceive emotion processes in some teenagers – a biomarker for low resilience which may lead to mental illnesses.”
Early stress may sensitize girls’ brains for later anxiety
High levels of family stress in infancy are linked to differences in everyday brain function and anxiety in teenage girls, according to new results of a long-running population study by University of Wisconsin-Madison scientists.
The study highlights evidence for a developmental pathway through which early life stress may drive these changes. Here, babies who lived in homes with stressed mothers were more likely to grow into preschoolers with higher levels of cortisol, a stress hormone. In addition, these girls with higher cortisol also showed less communication between brain areas associated with emotion regulation 14 years later. Last, both high cortisol and differences in brain activity predicted higher levels of adolescent anxiety at age 18.
The young men in the study did not show any of these patterns.
"We wanted to understand how stress early in life impacts patterns of brain development which might lead to anxiety and depression,” says first author Dr. Cory Burghy of the Waisman Laboratory for Brain Imaging and Behavior. "Young girls who, as preschoolers, had heightened cortisol levels, go on to show lower brain connectivity in important neural pathways for emotion regulation — and that predicts symptoms of anxiety during adolescence."
To test this, scans designed by Dr. Rasmus Birn, assistant professor of psychiatry in the UW School of Medicine and Public Health, showed that teenage girls whose mothers reported high levels of family stress when the girls were babies show reduced connections between the amygdala or threat center of the brain and the ventromedial prefrontal cortex, a part of the brain responsible for emotional regulation. Birn used a method called resting-state functional connectivity (fcMRI), which looks at the brain connections while the brain is at a resting state.
The study was published in Nature Neuroscience.
Research shows binge drinking inhibits brain development
Teenagers who binge drink risk inhibiting part of their brain’s development and many are laying the groundwork for alcoholism down the track a Queensland University of Technology (QUT) researcher has found.
Professor Selena Bartlett, from QUT’s Institute for Health and Biomedical Innovation (IHBI), studied the effect excessive binge drinking during adolescence had on a particular receptor in the brain and discovered teen bingeing altered it irreversibly, keeping the brain in an adolescent state.
"The human brain doesn’t fully develop until around age 25 and bingeing during adolescence modifies its circuits, preventing the brain from reaching maturity," she said.
"During adolescence, the brain undergoes massive changes in the prefrontal cortex and areas linked to drug reward but alcohol disrupts this.
"The research, which was carried out on rats, suggests that during ageing, the brain’s delta opioid peptide receptor (DOP-R) activity turns down, but binge drinking causes the receptors to stay on, keeping it in an adolescent stage.
"The younger a child or teenager starts binge drinking and the more they drink, the worse the possible outcome for them."
Professor Bartlett said recent trends to mix high-caffeine drinks such as Red Bull with alcohol were making the binge drinking problem worse.
"Blue" Light Could Help Teenagers Combat Stress
Adolescents can be chronically sleep deprived because of their inability to fall asleep early in combination with fixed wakeup times on school days. According to the CDC, almost 70 percent of school children get insufficient sleep—less than 8 hours on school nights. This type of restricted sleep schedule has been linked with depression, behavior problems, poor performance at school, drug use, and automobile accidents. A new study from the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute shows that exposure to morning short-wavelength “blue” light has the potential to help sleep-deprived adolescents prepare for the challenges of the day and deal with stress, more so than dim light.
The study was a collaboration between Associate Professor and Director of the LRC Light and Health Program Mariana Figueiro and LRC Director and Professor Mark S. Rea. Results of the study titled “Short-Wavelength Light Enhances Cortisol Awakening Response in Sleep-Restricted Adolescents,” were recently published in the open access International Journal of Endocrinology. The full text is available at http://www.hindawi.com/journals/ije/2012/301935/.