Excessive screen time among adolescents negatively impacts multiple aspects of sleep, which in turn increases the risk of depressive symptoms – particularly among girls. That is the conclusion of a new study published in the open-access journal PLOS Global Public Healthby Sebastian Hökby of Karolinska Institutet, Sweden, and colleagues.
Recently, the Swedish Public Health Agency published recommendations that adolescents use no more than two-to-three hours of daily leisure screen time, partly to promote better sleep. Previous studies have suggested associations between screen time, sleep disruptions, and depression in teens. However, sleep problems and depression often coincide, and the direction of these associations has been unclear.
In the new study, researchers tracked 4,810 Swedish students aged 12-16, collecting data on sleep quality and quantity, depressive symptoms, and screen usage at three timepoints over the course of a year.
The researchers found that increased screen time led to deteriorated sleep within three months, impacting both the duration and quality of sleep. Screen time was also found to postpone sleep times towards later hours – disrupting multiple aspects of the human sleep-wake cycle at once. Among boys, screen time had a direct adverse effect on depression after twelve months, while among girls the depressive effect was mediated through sleep disturbances. Sleep could explain about half (38%-57%) of the association between screen time and depression in girls. Boys who spent more time on screens also experienced sleep disruptions, but these were not strongly associated to later depression.
The authors summarize: “In this study, we found that adolescents who reported longer screen times also developed poorer sleep habits over time. In turn, this led to increased depression levels, especially among girls.”
They add: “Our results do suggest that less[…] screen time seems healthier, in line with previous World Health Organization statements…if screen times were somehow reduced, for example through public health policies, our results imply that the high burden of depressive states among young Swedish women, and maybe young men, would likely decrease.”
Adolescents who sleep for longer – and from an earlier bedtime – than their peers tend to have improved brain function and perform better at cognitive tests, researchers from the UK and China have shown.
But the study of adolescents in the US also showed that even those with better sleeping habits were not reaching the amount of sleep recommended for their age group.
Sleep plays an important role in helping our bodies function. It is thought that while we are asleep, toxins that have built up in our brains are cleared out, and brain connections are consolidated and pruned, enhancing memory, learning, and problem-solving skills. Sleep has also been shown to boost our immune systems and improve our mental health.
During adolescence, our sleep patterns change. We tend to start going to bed later and sleeping less, which affects our body clocks. All of this coincides with a period of important development in our brain function and cognitive development. The American Academy of Sleep Medicine says that the ideal amount of sleep during this period is between eight- and 10-hours’ sleep.
Professor Barbara Sahakian from the Department of Psychiatry at the University of Cambridge said: “Regularly getting a good night’s sleep is important in helping us function properly, but while we know a lot about sleep in adulthood and later life, we know surprisingly little about sleep in adolescence, even though this is a crucial time in our development. How long do young people sleep for, for example, and what impact does this have on their brain function and cognitive performance?”
Studies looking at how much sleep adolescents get usually rely on self-reporting, which can be inaccurate. To get around this, a team led by researchers at Fudan University, Shanghai, and the University of Cambridge turned to data from the Adolescent Brain Cognitive Development (ABCD) Study, the largest long-term study of brain development and child health in the United States.
As part of the ABCD Study, more than 3200 adolescents aged 11-12 years old had been given FitBits, allowing the researchers to look at objective data on their sleep patterns and to compare it against brain scans and results from cognitive tests. The team double-checked their results against two additional groups of 13-14 years old, totalling around 1190 participants. The results are published today in Cell Reports.
The team found that the adolescents could be divided broadly into one of three groups:
Group One, accounting for around 39% of participants, slept an average (mean) of 7 hours 10 mins. They tended to go to bed and fall asleep the latest and wake up the earliest.
Group Two, accounting for 24% of participants, slept an average of 7 hours 21 mins. They had average levels across all sleep characteristics.
Group Three, accounting for 37% of participants, slept an average of 7 hours 25 mins. They tended to go to bed and fall asleep the earliest and had lower heart rates during sleep.
Although the researchers found no significant differences in school achievement between the groups, when it came to cognitive tests looking at aspects such as vocabulary, reading, problem solving and focus, Group Three performed better than Group Two, which in turn performed better than Group One.
Group Three also had the largest brain volume and best brain functions, with Group One the smallest volume and poorest brain functions.
Professor Sahakian said: “Even though the differences in the amount of sleep that each group got was relatively small, at just over a quarter-of-an-hour between the best and worst sleepers, we could still see differences in brain structure and activity and in how well they did at tasks. This drives home to us just how important it is to have a good night’s sleep at this important time in life.”
First author Dr Qing Ma from Fudan University said: “Although our study can’t answer conclusively whether young people have better brain function and perform better at tests because they sleep better, there are a number of studies that would support this idea. For example, research has shown the benefits of sleep on memory, especially on memory consolidation, which is important for learning.”
The researchers also assessed the participants’ heart rates, finding that Group Three had the lowest heart rates across the sleep states and Group One the highest. Lower heart rates are usually a sign of better health, whereas higher rates often accompany poor sleep quality like restless sleep, frequent awakenings and excessive daytime sleepiness.
Because the ABCD Study is a longitudinal study – that is, one that follows its participants over time – the team was able to show that the differences in sleep patterns, brain structure and function, and cognitive performance, tended be present two years before and two years after the snapshot that they looked at.
Senior author Dr Wei Cheng from Fudan University added: “Given the importance of sleep, we now need to look at why some children go to bed later and sleep less than others. Is it because of playing videogames or smartphones, for example, or is it just that their body clocks do not tell them it’s time to sleep until later?”
The research was supported by the National Key R&D Program of China, National Natural Science Foundation of China, National Postdoctoral Foundation of China and Shanghai Postdoctoral Excellence Program. The ABCD Study is supported by the National Institutes of Health.
A recent study reveals that age plays a significant role in the outcomes of intermittent fasting. Researchers from Technical University of Munich (TUM), LMU Hospital Munich, and Helmholtz Munich discovered that chronic intermittent fasting disrupted the development of insulin-producing beta cells in young mice. The findings, published in Cell Reports, raise concerns about potential risks for humans, especially teenagers.
“Intermittent fasting is known to have benefits, including boosting metabolism and helping with weight loss and heart disease. But until now, its potential side effects weren’t well understood,” says Alexander Bartelt, the Else Kröner Fresenius Professor and Chair of Translational Nutritional Medicine at TUM. In a recently published study, the team shows that intermittent fasting during adolescence could have long-term negative effects on metabolism.
Fasting improves metabolism in older mice, but not in the young
The researchers studied three groups of mice: adolescent, adult, and older animals. The mice remained without food for one day and were fed normally on two days. After ten weeks, insulin sensitivity improved in both the adult and older mice, meaning that their metabolism responded better to insulin produced by the pancreas. This is key to regulating blood sugar levels and preventing conditions like type 2 diabetes.
However, the adolescent mice showed a troubling decline in their beta cell function, the insulin-producing cells of the pancreas. Insufficient insulin production is linked to diabetes and disrupted metabolism. “Intermittent fasting is usually thought to benefit beta cells, so we were surprised to find that young mice produced less insulin after the extended fasting,” explains Leonardo Matta from Helmholtz Munich, one of the study’s lead authors.
Defective beta cells resemble those of type 1 diabetes patients
The researchers used the latest single-cell sequencing to uncover the cause of the beta cell impairment. By examining the blueprint of the pancreas, the team found that the beta cells in the younger mice failed to mature properly. “At some point, the cells in the adolescent mice stopped developing and produced less insulin,” says Peter Weber from Helmholtz Munich, also a lead author. Older mice, whose beta cells were already mature before the fasting began, remained unaffected.
Beta cells from an older mouse.
The team compared their mouse findings to data from human tissues. They found that patients with type 1 diabetes, where beta cells are destroyed by an autoimmune response, showed similar signs of impaired cell maturation. This suggests that the findings from the mouse study could also be relevant to humans.
“Our study confirms that intermittent fasting is beneficial for adults, but it might come with risks for children and teenagers,” says Stephan Herzig, a professor at TUM and director of the Institute for Diabetes and Cancer at Helmholtz Munich. “The next step is digging deeper into the molecular mechanisms underlying these observations. If we better understand how to promote healthy beta cell development, it will open new avenues for treating diabetes by restoring insulin production.”
Empathy responses to others in pain peak in young adulthood according to a new study led by Kent’s School of Psychology. Psychologists have discovered that young adults are especially sensitive to social pain, such as situations of embarrassment, grief and sadness, and empathise more strongly with others experiencing social pain than adolescents or older adults do.
Empathy is a critical component of social interaction that enables individuals to understand and share the emotions of others.
The research, published in the journal Social Cognitive and Affective Neuroscience, explored how empathy responses differ between adolescents (10-19 years old), young adults (20-40 years old) and older adults (60+ years old), by recording brain activity while participants viewed photographs of people in physically or socially painful situations. Findings showed that brain responses to painful situations increased from adolescence to young and older adulthood. This demonstrates that empathy responses develop throughout the lifespan as social experience and exposure to different social and pain-related situations increases.
While the research showed that people’s brain empathy responses get stronger as they age, the increased brain activity in older adults comes alongside reduced ratings of pain for others. Professor Heather Ferguson, lead researcher on the paper and Professor of Psychology at Kent, suggests that this is because older adults are less good at expressing empathy for others compared to young adults.
Professor Ferguson said: ‘This study provides valuable insights into the complex nature of empathic responses to others in pain. Empathy responses to others in pain peak in young adulthood, as seen in their behavioural ratings of pain intensity felt by others. However, the brain becomes increasingly reactive to seeing others in pain as we age, which suggests that older adults experienced empathy at the time of viewing the photographs of pain – but were less accurate later at rating the intensity of this pain.’
Photo by Inzmam Khan: https://www.pexels.com/photo/man-in-black-shirt-and-gray-denim-pants-sitting-on-gray-padded-bench-1134204/
A study by researchers at the University of Helsinki and HUS Helsinki University Hospital found a significant association among adolescents between having psychotic-like experiences and depressive symptoms, as well as with self-destructive behaviours.
Psychotic-like experiences resemble symptoms of psychosis, but are milder, less frequent and much more common than psychotic disorders. While these symptoms do not constitute a disorder diagnosed as psychosis, they can still be disruptive, distressing or detrimental to functional capacity. Typical psychotic-like experiences include perceptual distortions and hallucinations, suspicious paranoid thinking, delusions and bizarre, unusual thoughts.
Psychotic-like experiences are abundant among adolescents referred to care, but are generally considered fairly neutral, with only some of the adolescents reporting them as frightening, worrisome or harmful. In the study, published in the journal Psychosis, the correlation between psychotic-like experiences and depressive symptoms turned out to be strong. This link was not explained by connections between individual psychotic-like experiences and depressive symptoms, but by factors that more broadly measure paranoia and unusual thoughts. In addition to depressive symptoms, paranoid thoughts and unusual thought content were also associated with self-destructive thinking.
Making questions about psychotic-like experiences part of care
The findings show that psychotic-like experiences should be systematically surveyed in all adolescents seeking psychiatric care. It should also be assessed how frightening, worrisome or harmful they are considered to be. Particularly in the case of responses emphasising bizarre thinking and exaggerated suspiciousness, attention should also be paid to assessing mood and self-destructive thinking, as these factors can remain hidden without further enquiry.
“Our findings provide a clear recommendation for treatment practices: psychotic-like experiences should be assessed as part of routine procedures, but it is also important to determine how they are perceived. These phenomena cannot be uncovered unless separately and systematically asked,” says the principal investigator, Docent Niklas Granö.
It should be clearly explained to adolescents and their families that these symptoms are common and often manageable. In addition, applications of cognitive psychotherapy, even brief interventions, can help adolescents understand their symptoms and alleviate the strain they cause.
Adolescents who meet the recommended guidelines of nine to 11 hours of sleep per day were shown to have a significantly lower risk of hypertension, according to a new study from UTHealth Houston.
Recently published in the Journal of the American Heart Association, the research revealed that adolescents had a 37% lower risk of developing incidents of high blood pressure by meeting healthy sleep patterns, and underscoring the importance of adequate sleep behaviour. The research further explored the impact of environmental factors potentially impacting sleep.
“Disrupted sleep can lead to changes in the body’s stress response, including elevated levels of stress hormones like cortisol, which in turn can increase blood pressure,” said first author Augusto César Ferreira De Moraes, PhD, assistant professor in the Department of Epidemiology at UTHealth Houston School of Public Health.
De Moraes and his team analysed data from 3320 adolescents across the US to investigate incidents of high blood pressure during nighttime sleep cycles. Scientists identified a rise in hypertension incidents over two data periods, 2018-2020 and 2020-2022, showing an increase from 1.7% to 2.9%. The data included blood pressure readings and Fitbit assessments, which measured total sleep time and REM sleep duration at night. The study’s design analysed covariates such as Fitbit-tracked sleep, blood pressure, and neighbourhood noise by residential geocodes, allowing for a thorough examination of environmental noise exposure for each participant.
Neighbourhood/community noise was not significantly associated with the incidence of hypertension. Environmental factors, such as neighbourhood noise, point to the need for longer-term studies to investigate the relationship between sleep health and hypertension, particularly in relation to socioeconomic status, stress levels, and genetic predispositions.
The study emphasises the importance of improved sleep behaviours and meeting recommendations. “Consistent sleep schedules, minimising screen time before bed, and creating a calm, quiet sleep environment can all contribute to better sleep quality,” advises Martin Ma, MPH, second author of the study and recent graduate of the school. “Although environmental noise didn’t directly affect hypertension in this study, maintaining a quiet and restful sleep environment is still important for overall well-being.”
Cannabis use may lead to thinning of the cerebral cortex in adolescents according to a recent study. The study demonstrates that THC – or tetrahydrocannabinol, an active substance in cannabis – causes shrinkage of the dendritic arborisation, neurons’ “network of antennae” whose role is critical for communication between neurons. This results in the atrophy of certain regions of the cerebral cortex – bad news at an age when the brain is maturing.
“If we take the analogy of the brain as a computer, the neurons would be the central processor, receiving all information via the synapses through the dendritic network,” explains Tomas Paus, who is also a professor of psychiatry and neuroscience at Université de Montréal. “So a decrease in the data input to the central processor by dendrites makes it harder for the brain to learn new things, interact with people, cope with new situations, etc. In other words, it makes the brain more vulnerable to everything that can happen in a young person’s life.”
A multi-level approach to better understand the effect on humans
This project is notable for the complementary, multi-level nature of the methods used. “By analysing magnetic resonance imaging (MRI) scans of the brains of a cohort of teenagers, we had already shown that young people who used cannabis before the age of 16 had a thinner cerebral cortex,” explains Tomas Paus. “However, this research method doesn’t allow us to draw any conclusions about causality, or to really understand THC’s effect on the brain cells.”
Given the limitations of MRI, the introduction of the mouse model by Graciela Pineyro’s team was key. “The model made it possible to demonstrate that THC modifies the expression of certain genes affecting the structure and function of synapses and dendrites,” explains Graciela Pineyro, who is also a professor in the Department of Pharmacology and Physiology at Université de Montréal. “The result is atrophy of the dendritic arborescence that could contribute to the thinning observed in certain regions of the cortex.”
Interestingly, these genes were also found in humans, particularly in the thinner cortical regions of the cohort adolescents who experimented with cannabis. By combining their distinct research methods, the two teams were thus able to determine with a high degree of certainty that the genes targeted by THC in the mouse model were also associated to the cortical thinning observed in adolescents.
With cannabis use on the rise among North American youth, and commercial cannabis products containing increasing concentrations of THC, it’s imperative that we improve our understanding of how this substance affects brain maturation and cognition. This successful collaborative study, involving cutting-edge techniques in cellular and molecular biology, imaging and bioinformatics analysis, is a step in the right direction for the development of effective public health measures.
In a review of 27 different studies, a Johns Hopkins Children’s Center team concludes that some video games created as mental health interventions can be helpful – if modest – tools in improving the mental well-being of children and teens with depression and attention-deficit/hyperactivity disorder (ADHD). They did not significantly help with anxiety, however.
A report on the review of studies from peer-reviewed journals between 2011 and March 20, 2024, was published in JAMA Pediatrics.
“We found literature that suggests that even doubling the number of paediatric mental health providers still wouldn’t meet the need,” says Barry Bryant, MD, a resident in the Department of Psychiatry and Behavioral Sciences in the Johns Hopkins University School of Medicine and first author of the new study.
In a bid to determine if so-called “gamified digital mental health interventions,” or video games designed to treat mental health conditions, benefited those with anxiety, depression and ADHD, the research team analysed their use in randomised clinical trials for children and adolescents.
Bryant and child and adolescent psychologist Joseph McGuire, PhD, identified 27 such trials from the US and around the world. The studies overall included 2911 participants with about half being boys and half being girls, ages six to 17 years old.
The digital mental health interventions varied in content, but were all created with the intent of treating ADHD, depression and anxiety. For example, for ADHD, some of the games involved racing or splitting attention, which required the user to pay attention to more than one activity to be successful in gameplay. For depression and anxiety, some of the interventions taught psychotherapy-oriented concepts in a game format. All games were conducted on technology platforms, such as computers, tablets, video game consoles and smartphones. The video games are available to users in a variety of ways. Some are available online, while others required access through specific research teams involved in the studies.
The research team’s analysis found that video games designed for patients with ADHD and depression provided a modest reduction (both with an effect size of .28) in symptoms related to ADHD and depression, such as improved ability to sustain attention and decreased sadness, based on participant and family feedback from the studies. (An effect size of .28 is consistent with a smaller effect size, where as in-person interventions often produce moderate [.50] to large [.80] effects.) By contrast, video games designed for anxiety did not show meaningful benefits (effect size of .07) for reducing anxiety symptoms for participants, based on participant and family feedback.
Researchers also examined factors that led to improved benefit from digital mental health interventions. Specific factors related to video game delivery (i.e., interventions on computers and those with preset time limits) and participants (i.e., studies that involved more boys) were found to positively influence therapeutic effects. Researchers say these findings suggest potential ways to improve upon the current modest symptom benefit.
“While the benefits are still modest, our research shows that we have some novel tools to help improve children’s mental health – particularly for ADHD and depression – that can be relatively accessible to families,” says Joseph McGuire, Ph.D., an author of the study and an associate professor of psychiatry and behavioural sciences in the school of medicine. “So if you are a paediatrician and you’re having trouble getting your paediatric patient into individual mental health care, there could be some gamified mental health interventions that could be nice first steps for children while waiting to start individual therapy.”
The team cautioned that their review did not indicate why certain video game interventions performed better than others. They also note that some of the trials included in the study used reported outcome measures, and the studies did not uniformly examine the same factors which could have influenced the effects of the treatment. Some of the video games included in the studies are not easily accessible to play.
The researchers also noted that while video game addiction and the amount of screen time can be concerns, those children who played the games studied in a structured, time-limited format tended to do best.
The average age at menarche, the first menstrual period, has been decreasing among younger generations in the US, especially those belonging to racial minorities and lower socioeconomic statuses, according to a new study led by researchers at Harvard T.H. Chan School of Public Health. It also found that the average time it takes for the menstrual cycle to become regular is increasing.
The study, published in JAMA Network Open, is the latest publication from the Apple Women’s Health Study, a longitudinal study of menstrual cycles, gynaecological conditions, and overall women’s health conducted by Harvard Chan School, the National Institute of Environmental Health Sciences, and Apple.
“Our findings can lead to a better understanding of menstrual health across the lifespan and how our lived environment impacts this critical vital sign,” said co-principal investigator Shruthi Mahalingaiah, assistant professor of environmental, reproductive, and women’s health at Harvard Chan School.
While previous studies have shown trends towards earlier menarche over the past five decades, data has been limited on how these trends present within different racial groups and socioeconomic statuses. Additionally, few studies have had sufficient data to identify any trends regarding time to menstrual cycle regularity.
The researchers used the Apple Women’s Health Study’s large, diverse dataset to fill this research gap. The 71 341 participants who enrolled between November 2018 and March 2023 self-reported the age at which they first began menstruating and their race and socioeconomic status. The researchers divided the participants into five age brackets: born between 1950–1969, 1970–1979, 1980–1989, 1990–1999, and 2000-2005. Ages of menarche were defined as early (younger than 11 years old), very early (younger than 9), and late (ages 16 and above). A subset of participants (61 932) self-reported the time it took for their menstrual cycle to become regular and were divided into five categories: up to two years, between three and four years, longer than five years, hasn’t become regular, or became regular with use of hormones. Another subset (9865) provided their body mass index (BMI) at their age of menarche.
The study found that as birth year increased (meaning younger participants), average age at menarche decreased and time from menarche to menstrual cycle regularity increased. Among participants born from 1950–1969, the average age at menarche was 12.5 years, and the rates of early and very early menarche were 8.6% and 0.6%, respectively. Among participants born from 2000–2005, the average age of menarche was 11.9 years, and the rates of early and very early menarche were 15.5% and 1.4%, respectively. Across the two groups, the percentage of participants who reached menstrual cycle regularity within two years of menarche decreased from 76% to 56%. The researchers observed that these trends were present among all sociodemographic groups but were most pronounced among the participants who identified as Black, Hispanic, Asian, or mixed race, and who rated themselves as belonging to a low socioeconomic status.
The findings showed that BMI at age of menarche could explain part of the trend toward periods starting earlier. Other possible factors that might explain the trend include dietary patterns, psychological stress and adverse childhood experiences, and environmental factors such as endocrine-disrupting chemicals and air pollution.
“Continuing to investigate early menarche and its drivers is critical,” said corresponding author Zifan Wang, postdoctoral research fellow in Harvard Chan School’s Department of Environmental Health. “Early menarche is associated with higher risk of adverse health outcomes, such as cardiovascular disease and cancer. To address these health concerns – which our findings suggest may begin to impact more people, with disproportionate impact on already disadvantaged populations – we need much more investment in menstrual health research.”
The authors noted some limitations to the study, including that it relies heavily on retrospective self-reporting.
A new study to be presented at the SLEEP 2024 annual meeting found a distinct relationship between sleep duration, social media usage, and brain activation across brain regions that are key for executive control and reward processing.
Results show a correlation between shorter sleep duration and greater social media usage in teens. The analysis points to involvement of areas within the frontolimbic brain regions, such as the inferior and middle frontal gyri, in these relationships. The inferior frontal gyrus, key in inhibitory control, may play a crucial role in how adolescents regulate their engagement with rewarding stimuli such as social media. The middle frontal gyrus, involved in executive functions and critical in assessing and responding to rewards, is essential in managing decisions related to the balancing of immediate rewards from social media with other priorities like sleep. These results suggest a nuanced interaction between specific brain regions during adolescence and their influence on behaviour and sleep in the context of digital media usage.
“As these young brains undergo significant changes, our findings suggest that poor sleep and high social media engagement could potentially alter neural reward sensitivity,” said Orsolya Kiss, who has a doctorate in cognitive psychology and is a research scientist at SRI International. “This intricate interplay shows that both digital engagement and sleep quality significantly influence brain activity, with clear implications for adolescent brain development.”
This study involved data from 6516 adolescents, aged 10–14 years, from the Adolescent Brain Cognitive Development Study. Participants answered questionnaires about sleep duration and recreational social media use. Brain activities were analysed from functional MRI scans during the monetary incentive delay task, targeting regions associated with reward processing. The study used three different sets of models and switched predictors and outcomes each time. Results were adjusted for age, COVID-19 pandemic timing, and socio-demographic characteristics.
Kiss noted that these results provide new insights into how two significant aspects of modern adolescent life, social media usage and sleep duration, interact and impact brain development.
“Understanding the specific brain regions involved in these interactions helps us identify potential risks and benefits associated with digital engagement and sleep habits,” Kiss said. “This knowledge is especially important as it could guide the development of more precise, evidence-based interventions aimed at promoting healthier habits.”
The American Academy of Sleep Medicine recommends that teenagers 13 to 18 years of age should sleep 8 to 10 hours on a regular basis. The AASM also encourages adolescents to disconnect from all electronic devices at least 30 minutes to an hour before bedtime.
