̽��ֱ�� of Cambridge - adolescents

Adolescents who sleep longer perform better at cognitive tasks

cjb250 — Tue, 22 Apr 2025 15:00:23 +0000

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. ̽��ֱ��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 ̽��ֱ�� 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 ̽��ֱ��, Shanghai, and the ̽��ֱ�� 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 3,200 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. ̽��ֱ��team double-checked their results against two additional groups of 13-14 years old, totalling around 1,190 participants. ̽��ֱ��results are published today in Cell Reports.

̽��ֱ��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 ̽��ֱ�� 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.”

̽��ֱ��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 ̽��ֱ�� 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?”

̽��ֱ��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. ̽��ֱ��ABCD Study is supported by the National Institutes of Health.

Reference

Ma, Q et al. Neural correlates of device-based sleep characteristics in adolescents. Cell Reports; 22 Apr 2025; DOI: 10.1016/j.celrep.2025.115565

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.

Even though the differences in the amount of sleep that each group got was relatively small, we could still see differences in brain structure and activity and in how well they did at tasks

Barbara Sahakian

harpazo_hope (Getty Images)

Teenager asleep and wrapped in a blanket

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Cambridge leads governmental project to understand impact of smartphones and social media on young people

cjb250 — Thu, 16 Jan 2025 00:01:37 +0000

̽��ֱ��work has been commissioned by the UK government’s Department for Science, Innovation and Technology after a review by the UK Chief Medical Officer in 2019 found the evidence base around the links to children’s mental health were insufficient to provide strong conclusions suitable to inform policy.

̽��ֱ��project – led by a team at the ̽��ֱ�� of Cambridge, in collaboration with researchers at several leading UK universities – is aimed at improving policymakers’ understanding of the relationship between children’s wellbeing and smartphone use, including social media and messaging. It will help direct future government action in this area.

Project lead Dr Amy Orben from the Medical Research Council Cognition and Brain Sciences Unit (MRC CBU) at the ̽��ֱ�� of Cambridge said: “There is huge concern about the impact of smartphone use on children's health, but the evidence base remains fairly limited. While the government is under substantial time pressure to make decisions, these will undoubtedly be better if based on improved evidence.

“This is a complex and rapidly evolving issue, with both potential harms and benefits associated with smartphone use. Technology is changing by the day, and scientific evidence creation needs to evolve and innovate to keep up.

“Our focus will be on deepening our causal understanding of the effects of new technologies, particularly over short timescales, to ensure that decisions are informed, timely and evidence-based.”

Dr Orben will lead a Project Delivery Team, with Consortium Members from the universities of Bath, Birmingham, Bristol, Glasgow, Manchester, Nottingham, Oxford and York and the London School of Economics. It will aim to identify which research methods and data sources will be most effective at identifying potential causal relationships between social media, smartphones, and the health and development of children and young people

Deputy project lead Dr Amrit Kaur Purba, also from the MRC CBU at Cambridge, said: “ ̽��ֱ��impact of social media on young people is a pressing issue, and our project will ensure the research community is in a strong position to provide policymakers with the causal and high-quality insights they need. While we don’t expect this to be straightforward, our research will leverage diverse expertise from across the UK to deliver a comprehensive and informed response to make recommendations for how research in this area should be supported in future.”

̽��ֱ��researchers will review and summarise existing research on the impact of smartphones and social media on children and young people’s mental health, wellbeing, physical health, lifestyle and health behaviours, and educational attainment. ̽��ֱ��review will recognise the diversity of perspectives that exist in this area and consider where further research could add valuable new insights to the evidence base.

They will assess the various methods and data available to understand the causal impacts, including recognising that online habits and emerging technologies are changing at a rapid pace, and considering how the experiences of vulnerable children and young people – for example, LGBTQ+ young people and those with special needs or mental health issues – can be captured in future research projects.

This will allow the team to recommend and outline how future research studies could deliver robust and causal evidence on the impact of smartphones and social media on child development factors in the next two to three years.

Technology Secretary Peter Kyle, said: " ̽��ֱ��online world offers immense opportunities for young people to connect and learn. Ensuring they can do so in an environment which puts their safety first is my priority and will guide this government’s action on online safety.

“That’s why we have launched new research, led by the ̽��ֱ�� of Cambridge with support from other top UK universities, to better understand the complex relationship between technology and young people's wellbeing.

“This vital research will build a trusted evidence base for future action, helping us to protect and empower the next generation towards a safer and more positive digital future."

Cambridge researchers are leading the first phase of a new research project that will lay the groundwork for future studies into the impact on children of smartphone and social media use.

This is a complex and rapidly evolving issue, with both potential harms and benefits associated with smartphone use. Technology is changing by the day, and scientific evidence creation needs to evolve and innovate to keep up

Amy Orben

Owen Franken

Teenager holding a smartphone

Yes

Time alone heightens ‘threat alert’ in teenagers – even when connecting online

fpjl2 — Wed, 13 Nov 2024 09:03:21 +0000

People in their late teens experience an increased sensitivity to threats after just a few hours left in a room on their own – an effect that endures even if they are interacting online with friends and family.

This is according to latest findings from a cognitive neuroscience experiment conducted at the ̽��ֱ�� of Cambridge, which saw 40 young people aged 16-19 undergo testing before and after several hours alone – both with and without their smartphones.

Many countries have declared an epidemic of loneliness*. ̽��ֱ��researchers set out to “induce” loneliness in teenagers and study the effects through a series of tests, from a Pavlovian task to electrodes that measure sweat.

Scientists found that periods of isolation, including those in which participants could use their phones, led to an increased threat response – the sensing of and reacting to potential dangers. This alertness can cause people to feel anxious and uneasy.

̽��ֱ��authors of the study say that isolation and loneliness might lead to excessive “threat vigilance”, even when plugged in online, which could negatively impact adolescent mental health over time.

They say it could contribute to the persistent and exaggerated fear responses typical of anxiety disorders on the rise among young people around the world.

While previous studies show isolation leads to anxious behaviour and threat responses in rodents, this is believed to be the first study to demonstrate these effects through experiments involving humans.

̽��ֱ��findings are published today in the journal Royal Society Open Science.

“We detected signs of heightened threat vigilance after a few hours of isolation, even when the adolescents had been connected through smartphones and social media,” said Emily Towner, study lead author from Cambridge’s Department of Psychology.

“This alertness to perceived threats might be the same mechanism that leads to the excessive worry and inability to feel safe which characterises anxiety,” said Towner, a Gates Cambridge Scholar.

“It makes evolutionary sense that being alone increases our vigilance to potential threats. These threat response mechanisms undergo a lot of changes in adolescence, a stage of life marked by increasing independence and social sensitivity.”

"Our experiment suggests that periods of isolation in adolescents might increase their vulnerability to the development of anxiety, even when they are connected virtually.”

Researchers recruited young people from the local area in Cambridge, UK, conducting extensive screening to create a pool of 18 boys and 22 girls who had good social connections and no history of mental health issues.

Participants were given initial tests and questionnaires to establish a “baseline”. These included the Pavlovian threat test, in which they were shown a series of shapes on a screen, one of which was paired with a harsh noise played through headphones, so the shape became associated with a feeling of apprehension.

Electrodes attached to fingers monitored “electrodermal activity” – a physiological marker of stress – throughout this test.**

Each participant returned for two separate stints of around four hours isolated in a room in Cambridge ̽��ֱ��’s Psychology Department, after which the tests were completed again. There was around a month, on average, between sessions.

All participants underwent two isolation sessions. One was spent with a few puzzles to pass the time, but no connection to the outside world. For the other, participants were allowed smartphones and given wi-fi codes, as well as music and novels. ̽��ֱ��only major rule in both sessions was they had to stay awake.***

“We set out to replicate behaviour in humans that previous animal studies had found after isolation,” said Towner. “We wanted to know about the experience of loneliness, and you can’t ask animals how lonely they feel.”

Self-reported loneliness increased from baseline after both sessions. It was lower on average after isolation with social media, compared to full isolation.****

However, participants found the threat cue – the shape paired with a jarring sound – more anxiety-inducing and unpleasant after both isolation sessions, with electrodes also measuring elevated stress activity.

On average across the study, threat responses were 70% higher after the isolation sessions compared to the baseline, regardless of whether participants had been interacting digitally.

“Although virtual social interactions helped our participants feel less lonely compared to total isolation, their heightened threat response remained,” said Towner.

Previous studies have found a link between chronic loneliness and alertness to threats. ̽��ֱ��latest findings support the idea that social isolation may directly contribute to heightened fear responses, say researchers.

Dr Livia Tomova, co-senior author and lecturer in Psychology at Cardiff ̽��ֱ��, who conducted the work while at Cambridge, added: “Loneliness among adolescents around the world has nearly doubled in recent years. ̽��ֱ��need for social interaction is especially intense during adolescence, but it is not clear whether online socialising can fulfil this need.

“This study has shown that digital interactions might not mitigate some of the deep-rooted effects that isolation appears to have on teenagers.”

Scientists say the findings might shed light on the link between loneliness and mental health conditions such as anxiety disorders, which are on the rise in young people.

Notes

*For example, in 2023 the U.S. Surgeon General declared an epidemic of loneliness and isolation.

**Electrodes placed on the fingers record small deflections in sweat and subsequent changes in electrical conductivity of the skin (electrodermal activity). Electrodermal activity is used to detect stress levels and increases with emotional or physical arousal.

*** ̽��ֱ��baseline tests were always taken first. ̽��ֱ��order of the two isolation sessions was randomly allocated. For sessions with digital interactions allowed, most participants used social media (35 out of 40), with texting being the most common form of interaction (37 out of 40). Other popular platforms included Snapchat, Instagram, and WhatsApp. Participants mainly connected virtually with friends (38), followed by family (19), romantic partners (13), and acquaintances (4).

**** Average self-reported loneliness more than doubled after the isolation session with social media compared to baseline and nearly tripled after the complete isolation session compared to baseline.

Yes

Problems with ‘pruning’ brain connections linked to adolescent mental health disorders

cjb250 — Mon, 24 Apr 2023 15:00:34 +0000

̽��ֱ��findings, from an international collaboration, led by researchers in the UK, China and Germany, may help explain why people are often affected by more than one mental health disorder, and may in future help identify those at greatest risk.

One in seven adolescents (aged 10-19 years old) worldwide experiences mental health disorders, according to the World Health Organization (WHO). Depression, anxiety and behavioural disorders, such as attention deficit hyperactivity disorder (ADHD), are among the leading causes of illness and disability among young people, and adolescents will commonly have more than one mental health disorder.

Many mental health problems emerge during adolescence. Among these are disorders such as depression and anxiety, which manifest as ‘internalising’ symptoms, including low mood and worrying. Other conditions such as attention deficit hyperactivity disorder (ADHD) manifest as ‘externalising’ symptoms, such as impulsive behaviour.

Professor Barbara Sahakian from the Department of Psychiatry at the ̽��ֱ�� of Cambridge said: “Young people often experience multiple mental health disorders, beginning in adolescence and continuing – and often transforming – into adult life. This suggests that there’s a common brain mechanism that could explain the onset of these mental health disorders during this critical time of brain development.”

In a study published today in Nature Medicine, the researchers say they have identified a characteristic pattern of brain activity among these adolescents, which they have termed the ‘neuropsychopathological factor’, or NP factor for short.

̽��ֱ��team examined data from 1,750 adolescents, aged 14 years, from the IMAGEN cohort, a European research project examining how biological, psychological, and environmental factors during adolescence may influence brain development and mental health. In particular, they examined imaging data from brain scans taken while participants took part in cognitive tasks, looking for patterns of brain connectivity – in other words, how different regions of the brain communicate with each other.

Adolescents who experienced mental health problems – regardless of whether their disorder was one of internalising or externalising symptoms, or whether they experienced multiple disorders – showed similar patterns of brain activity. These patterns – the NP factor – were largely apparent in the frontal lobes, the area at the front of the brain responsible for executive function which, among other functions, controls flexible thinking, self-control and emotional behaviour.

̽��ֱ��researchers confirmed their findings by replicating them in 1,799 participants from the ABCD Study in the USA, a long-term study of brain development and child health, and by studying patients who had received psychiatric diagnoses.

When the team looked at genetic data from the IMAGEN cohort, they found that the NP factor was strongest in individuals who carried a particular variant of the gene IGSF11 that has been previously associated with multiple mental health disorders. This gene is known to play an important role in synaptic pruning, a process whereby unnecessary brain connections – synapses – are discarded. Problems with pruning may particularly affect the frontal lobes, since these regions are the last brain areas to complete development in adolescents and young adults.

Dr Tianye Jia from the Institute of Science and Technology for Brain-Inspired Intelligence, Fudan ̽��ֱ��, Shanghai, China and the Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK said: “As we grow up, our brains make more and more connections. This is a normal part of our development. But too many connections risk making the brain inefficient. Synaptic pruning helps ensure that brain activity doesn’t get drowned out in ‘white noise’.

“Our research suggests that when this important pruning process is disrupted, it affects how brain regions talk to each other. As this impact is seen most in the frontal lobes, this then has implications for mental health.”

̽��ֱ��researchers say that the discovery of the NP factor could help identify those young people at greatest risk of compounding mental health problems.

Professor Jianfeng Feng from Fudan ̽��ֱ�� in Shanghai, China, and the ̽��ֱ�� of Warwick, UK, said: “We know that many mental health disorders begin in adolescence and that individuals who develop one disorder are at increased risk of developing other disorders, too. By examining brain activity and looking for this NP factor, we might be able to detect those at greatest risk sooner, offering us more opportunity to intervene and reduce this risk.”

Funders included: the National Natural Science Foundation of China, European Union, National Institute for Health & Care Research (UK) and National Institutes of Health (NIH, USA).*

Reference
Chao Xie et al. A shared neural basis underlying psychiatric comorbidity. Nat Med; 24 Apr 2023: DOI: 10.1038/s41591-023-02317-4

*A full list of funders can be found in the paper.

Problems with the brain’s ability to ‘prune’ itself of unnecessary connections may underlie a wide range of mental health disorders that begin during adolescence, according to research published today.

Young people often experience multiple mental health disorders, beginning in adolescence and continuing – and often transforming – into adult life

Barbara Sahakian

Warren Wong

Teenager sitting near graffiti

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Lack of computer access linked to poorer mental health in young people during COVID-19 pandemic

cjb250 — Mon, 14 Nov 2022 08:00:07 +0000

̽��ֱ��team found that the end of 2020 was the time when young people faced the most difficulties and that the mental health of those young people without access to a computer tended to deteriorate to a greater extent than that of their peers who did have access.

̽��ֱ��COVID-19 pandemic had a significant effect on young people’s mental health, with evidence of rising levels of anxiety, depression, and psychological distress. Adolescence is a period when people are particularly vulnerable to developing mental health disorders, which can have long-lasting consequences into adulthood. In the UK, the mental health of children and adolescents was already deteriorating before the pandemic, but the proportion of people in this age group likely to be experiencing a mental health disorder increased from 11% in 2017 to 16% in July 2020.

̽��ֱ��pandemic led to the closure of schools and an increase in online schooling, the impacts of which were not felt equally. Those adolescents without access to a computer faced the greatest disruption: in one study 30% of school students from middle-class homes reported taking part in live or recorded school lessons daily, while only 16% of students from working-class homes reported doing so.

In addition to school closures, lockdown often meant that young people could not meet their friends in person. During these periods, online and digital forms of interaction with peers, such as through video games and social media, are likely to have helped reduce the impact of these social disruptions.

Tom Metherell, who at the time of the study was an undergraduate student at Fitzwilliam College, ̽��ֱ�� of Cambridge, said: “Access to computers meant that many young people were still able to ‘attend’ school virtually, carry on with their education to an extent and keep up with friends. But anyone who didn’t have access to a computer would have been at a significant disadvantage, which would only risk increasing their sense of isolation.”

To examine in detail the impact of digital exclusion on the mental health of young people, Metherell and colleagues examined data from 1,387 10–15-year-olds collected as part of Understanding Society, a large UK-wide longitudinal survey. They focused on access to computers rather than smartphones, as schoolwork is largely possible only on a computer while at this age most social interactions occur in person at school.

̽��ֱ��results of their study are published in Scientific Reports.

Participants completed a questionnaire that assesses common childhood psychological difficulties, which allowed the Understanding Society team to score them on five areas: hyperactivity/inattention, prosocial behaviour, emotional, conduct and peer relationship problems. From this, they derived a ‘Total Difficulties’ score for each individual.

Over the course of the pandemic, the researchers noted small changes in overall mental health of the group, with average Total Difficulties scores increasing form pre-pandemic levels of 10.7 (out of a maximum 40), peaking at 11.4 at the end of 2020 before declining to 11.1 by March 2021.

Those young people who had no access to a computer saw the largest increase in their Total Difficulties scores. While both groups of young people had similar scores at the start of the pandemic, when modelled with adjustment for sociodemographic factors, those without computer access saw their average scores increase to 17.8, compared to their peers, whose scores increased to 11.2. Almost one in four (24%) young people in the group without computer access had Total Difficulties scores classed as ‘high’ or ‘very high’ compared to one in seven (14%) in the group with computer access.

Metherell, now a PhD student at UCL, added: “Young people’s mental health tended to suffer most during the strictest periods of lockdown, when they were less likely to be able go to school or see friends. But those without access to a computer were the worst hit – their mental health suffered much more than their peers and the change was more dramatic.”

Dr Amy Orben from the Medical Research Council (MRC) Cognition and Brain Sciences at the ̽��ֱ�� of Cambridge, the study’s senior author, added: “Rather than always focusing on the downsides of digital technology on young people’s mental health, we need to recognise that it can have important benefits and may act as a buffer for their mental health during times of acute social isolation, such as the lockdown.

“We don’t know if and when a future lockdown will occur, but our research shows that we need to start thinking urgently how we can tackle digital inequalities and help protect the mental health of our young people in times when their regular in-person social networks are disrupted.”

̽��ֱ��researchers argue that policymakers and public health officials need to recognise the risks of ‘digital exclusion’ to young people’s mental health and prioritise ensuring equitable digital access.

Dr Amy Orben is a Research Fellow at Emmanuel College, Cambridge.

Tom Metherell was supported by was supported by the British Psychological Society Undergraduate Research Assistantship Scheme. ̽��ֱ��research was largely funded by the Medical Research Council.

Reference
Metherell, T et al. Digital access constraints predict worse mental health among adolescents during COVID-19. Scientific Reports; 9 Nov 2022; DOI: 10.1038/s41598-022-23899-y

Cambridge researchers have highlighted how lack of access to a computer was linked to poorer mental health among young people and adolescents during COVID-19 lockdowns.

Young people’s mental health tended to suffer most during the strictest periods of lockdown, when they were less likely to be able go to school or see friends

Tom Metherell

Thomas Park

Boy taking part in a virtual lesson

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Cannabis users no less likely to be motivated or able to enjoy life’s pleasure

cjb250 — Thu, 01 Sep 2022 07:56:00 +0000

Cannabis users also show no difference in motivation for rewards, pleasure taken from rewards, or the brain’s response when seeking rewards, compared to non-users.

Cannabis is the third most commonly used controlled substance worldwide, after alcohol and nicotine. A 2018 report from the NHS Digital Lifestyles Team stated that almost one in five (19%) of 15-year-olds in England had used cannabis in the previous 12 months, while in 2020 the National Institute on Drug Abuse reported the proportion in the United States to be 28% of 15-16-year-olds.

A common stereotype of cannabis users is the ‘stoner’ – think Jesse Pinkman in Breaking Bad, ̽��ֱ��Dude in ̽��ֱ��Big Lebowski, or, more recently, Argyle in Stranger Things. These are individuals who are generally depicted as lazy and apathetic.

At the same time, there has been considerable concern of the potential impact of cannabis use on the developing brain and that using cannabis during adolescence might have a damaging effect at an important time in an individual’s life.

A team led by scientists at UCL, the ̽��ֱ�� of Cambridge and the Institute of Psychiatry, Psychology & Neuroscience at King’s College London carried out a study examining whether cannabis users show higher levels of apathy (loss of motivation) and anhedonia (loss of interest in or pleasure from rewards) when compared to controls and whether they were less willing to exert physical effort to receive a reward. ̽��ֱ��research was part of the CannTEEN study.

̽��ֱ��results are published in the International Journal of Neuropsychopharmacology.

̽��ֱ��team recruited 274 adolescent and adult cannabis users who had used cannabis at least weekly over the past three months, with an average of four days per week, and matched them with non-users of the same age and gender.

Participants completed questionnaires to measure anhedonia, asking them to rate statements such as 'I would enjoy being with family or close friends'. They also completed questionnaires to measure their levels of apathy, which asked them to rate characteristics such as how interested they were in learning new things or how likely they were to see a job through to the end.

Cannabis users scored slightly lower than non-users on anhedonia – in other words, they appeared better able to enjoy themselves – but there was no significant difference when it came to apathy. ̽��ֱ��researchers also found no link between frequency of cannabis use and either apathy or anhedonia in the people who used cannabis.

Martine Skumlien, a PhD candidate in the Department of Psychiatry at the ̽��ֱ�� of Cambridge, said: “We were surprised to see that there was really very little difference between cannabis users and non-users when it came to lack of motivation or lack of enjoyment, even among those who used cannabis every day. This is contrary to the stereotypical portrayal we see on TV and in movies.”

In general, adolescents tended to score higher than adults on anhedonia and apathy in both user and non-user groups, but cannabis use did not augment this difference.

Dr Will Lawn, from the Institute of Psychiatry, Psychology and Neuroscience at King’s College London, said: “There’s been a lot of concern that cannabis use in adolescence might lead to worse outcomes than cannabis use during adulthood. But our study, one of the first to directly compare adolescents and adults who use cannabis, suggests that adolescents are no more vulnerable than adults to the harmful effects of cannabis on motivation, the experience of pleasure, or the brain’s response to reward.

“In fact, it seems cannabis may have no link – or at most only weak associations – with these outcomes in general. However, we need studies that look for these associations over a long period of time to confirm these findings.”

Just over half of participants also carried out a number of behavioural tasks. ̽��ֱ��first of these assessed physical effort. Participants were given the option to perform button-presses in order to win points, which were later exchanged for chocolates or sweets to take home. There were three difficulty levels and three reward levels; more difficult trials required faster button pressing. On each trial the participant could choose to accept or reject the offer; points were only accrued if the trial was accepted and completed.

In a second task, measuring how much pleasure they received from rewards, participants were first told to estimate how much they wanted to receive each of three rewards (30 seconds of one of their favourite songs, one piece of chocolate or a sweet, and a £1 coin) on a scale from ‘do not want at all’ to ‘intensely want’. They then received each reward in turn and were asked to rate how pleasurable they found them on a scale from ‘do not like at all’ to ‘intensely like’.

̽��ֱ��researchers found no difference between users and non-users or between age groups on either the physical effort task or the real reward pleasure task, confirming evidence from other studies that found no, or very little, difference.

Skumlien added: “We’re so used to seeing ‘lazy stoners’ on our screens that we don’t stop to ask whether they’re an accurate representation of cannabis users. Our work implies that this is in itself a lazy stereotype, and that people who use cannabis are no more likely to lack motivation or be lazier than people who don’t.

“Unfair assumptions can be stigmatising and could get in the way of messages around harm reduction. We need to be honest and frank about what are and are not the harmful consequences of drug use.”

Earlier this year, the team published a study that used functional magnetic resonance imaging (fMRI) to look at brain activity in the same participants as they took part in a brain imaging task measuring reward processing. ̽��ֱ��task involved participants viewing orange or blue squares while in the scanner. ̽��ֱ��orange squares would lead to a monetary reward, after a delay, if the participant made a response.

̽��ֱ��researchers used this set up to investigate how the brain responds to rewards, focusing in particular on the ventral striatum, a key region in the brain’s reward system. They found no relationship between activity in this region and cannabis use, suggesting that cannabis users had similar reward systems as non-users.

Professor Barbara Sahakian, from the Department of Psychiatry at the ̽��ֱ�� of Cambridge, said: “Our evidence indicates that cannabis use does not appear to have an effect on motivation for recreational users. ̽��ֱ��participants in our study included users who took cannabis on average four days a week and they were no more likely to lack motivation. However, we cannot rule out the possibility that greater use, as seen in some people with cannabis-use disorder, has an effect.

“Until we have future research studies that follow adolescent users, starting from onset through to young adulthood, and which combine measures of motivation and brain imaging, we cannot determine for certain that regular cannabis use won’t negatively impact motivation and the developing brain.”

This research was funded by the Medical Research Council with additional support from the Aker Foundation, National Institute for Health Research and Wellcome.

References

Skumlien, M, et al. Anhedonia, apathy, pleasure, and effort-based decision-making in adult and adolescent cannabis users and controls. IJNP; 24 Aug 2022; DOI: 10.1093/ijnp/pyac056

Skumlien, M, et al. Neural responses to reward anticipation and feedback in adult and adolescent cannabis users and controls. Neuropsychopharmacology; 6 April 2022; DOI: 10.1038/s41386-022-01316-2

Adult and adolescent cannabis users are no more likely than non-users to lack motivation or be unable to enjoy life’s pleasure, new research has shown, suggesting there is no scientific basis for the stereotype often portrayed in the media.

We’re so used to seeing ‘lazy stoners’ on our screens that we don’t stop to ask whether they’re an accurate representation of cannabis users. Our work implies that this is in itself a lazy stereotype

Martine Skumlien

jopstock (Getty Images)

Female hands rolling a marijuana joint

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̽��ֱ��psychiatrist who faced a dilemma but couldn’t turn his back on his people

cg605 — Mon, 23 May 2022 13:09:49 +0000

Children in West Africa with cognitive difficulties are going undiagnosed because the tests used to assess their mental health are based on Western norms. Kwabena Kusi-Mensah is working with communities in Nigeria and Ghana to develop assessments that are culturally appropriate.

High insulin levels during childhood a risk for mental health problems later in life, study suggests

sc604 — Wed, 13 Jan 2021 16:00:00 +0000

̽��ֱ��researchers, led by the ̽��ֱ�� of Cambridge, used a sample of over 10,000 people to study how insulin levels and body mass index (BMI) in childhood may be linked with depression and psychosis in young adulthood.

They found that persistently high insulin levels from mid-childhood were linked with a higher chance of developing psychosis in adulthood. In addition, they found that an increase in BMI around the onset of puberty was linked with a higher chance of developing depression in adulthood, particularly in girls. ̽��ֱ��results were consistent after adjusting for a range of other possible factors.

̽��ֱ��findings, reported in the journal JAMA Psychiatry, suggest that early signs of developing physical health problems could be present long before the development of symptoms of psychosis or depression and show that the link between physical and mental illness is more complex than previously thought.

However, the researchers caution that these risk factors are among many, both genetic and environmental, and that their results do not suggest that one could predict the likelihood of developing adult mental disorders from these physical health measures alone.

̽��ֱ��researchers recommend that healthcare professionals should carry out robust physical assessments of young people presenting with symptoms of psychosis or depression, so that early signs of physical illnesses may be diagnosed and treated early. It has been well-established that people with depression and psychosis can have a life expectancy of up to 20 years shorter than the general population, mostly because physical health problems like diabetes and obesity are more common in adults with those mental disorders.

While psychosis and depression in adulthood are already known to be associated with significantly higher rates of diabetes and obesity than the general population, these links are often attributed to the symptoms of the mental disorder itself.

“ ̽��ֱ��general assumption in the past has been that some people with psychosis and depression might be more likely to have a poor diet and lower levels of physical exercise, so any adverse physical health problems are a result of the mental disorder, or the treatment for it,” said first author Dr Benjamin Perry from Cambridge’s Department of Psychiatry. “In essence, the received wisdom is that the mental disorder comes first. But we’ve found that this isn’t necessarily the case, and for some individuals, it may be the other way around, suggesting that physical health problems detectable from childhood might be risk factors for adult psychosis and depression.”

Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC), a long-term population-representative birth cohort study set in the west of England, Perry and his colleagues found that disruption to insulin levels can be detected in childhood, long before the onset of psychosis, suggesting that some people with psychosis may have an inherent susceptibility to developing diabetes.

They used a statistical method to group individuals based on similar trajectories of change in insulin levels and BMI from age one to 24, and examined how the different groups related to risks of depression and psychosis in adulthood. About 75% of study participants had normal insulin levels, between 15% and 18% had insulin levels which increased gradually over adolescence, and around 3% had relatively high insulin levels. This third group had a higher chance of developing psychosis in adulthood compared with the average group.

̽��ֱ��researchers did not find that the group who had persistently high BMI through childhood and adolescence had a significantly increased risk of depression in adulthood, and instead suggest that their findings mean that certain factors around the age of puberty which might cause BMI to increase might be important risk factors for depression in adulthood. ̽��ֱ��researchers were not able to determine in their study what those factors might be, and future research will be required to find them. These factors might be important targets to reduce the risk of depression in adulthood.

“These findings are an important reminder that all young people presenting with mental health problems should be offered a full and comprehensive assessment of their physical health in tandem with their mental health,” said Perry. “Intervening early is the best way to reduce the mortality gap sadly faced by people with mental disorders like depression and psychosis.

“ ̽��ֱ��next step will be to work out exactly why persistently high insulin levels from childhood increase the risk of psychosis in adulthood, and why increases in BMI around the age of puberty increase the risk of depression in adulthood. Doing so could pave the way for better preventative measures and the potential for new treatment targets.”

Reference:
Benjamin I. Perry et al: ‘Longitudinal Trends in Insulin Levels and BMI From Childhood and Their Associations with Risks of Psychosis and Depression in Young Adults.’ JAMA Psychiatry (2021). DOI: 10.1001/jamapsychiatry.2020.4180

Researchers have shown that the link between physical and mental illness is closer than previously thought. Certain changes in physical health, which are detectable in childhood, are linked with the development of mental illness in adulthood.

For some individuals, physical health problems detectable from childhood might be risk factors for adult psychosis and depression

Benjamin Perry

Piron Guillaume via Unsplash

Children sitting on park bench

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