Children's mental health, and mapping bilingual brains
PodcastsThe Naked ScientistsChildren's mental health, and mapping bilingual brainsPlus, what is the best way to recycle plastic?03 July 2026Coming up: England's mental health services are reportedly in. . .
PodcastsThe Naked ScientistsChildren's mental health, and mapping bilingual brainsPlus, what is the best way to recycle plastic?03 July 2026Coming up: England's mental health services are reportedly in "crisis", with over 1 million children referred. What is driving the uptick? Plus, new research suggests that antibodies protect against norovirus, strategies to improve plastic recycling rates, and insights into the bilingual brain. Children's mental health caseload rocketsBarbara Sahakian, University of CambridgeEngland’s children’s commissioner, Rachel de Souza, has warned that the country is facing a “crisis” after more than 1 million children were referred to its mental health services. A new report says numbers are up by 10% on last year, and there are now around twice as many referrals for children and young people than there were eight years ago. But what is driving it? And do we see similar trends elsewhere? Rachael Ralph went to meet Barbara Sahakian, a professor of clinical neuropsychology and an expert in ADHD at the University of Cambridge. Barbara has just returned from the International College of Neuropsychopharmacology - or CINP - Congress in Glasgow…Barbara - There's increases across a number of different mental health disorders, in particular anxiety but also depression. Those are very common mental health disorders. And then there's also increased diagnoses of autism and attention deficit hyperactivity disorder or ADHD. Rachael - And what do we think is driving these?Barbara - Well there's probably a number of drivers and they may be different for different things. I mean one thing that has been pointed out is, you know, internet use and social media where people are trying to fit into perfect mould of what they think they should look like and things like that. There's also some bullying that goes on and so there's exposure to things like pornography which young people shouldn't be seeing. So there's a whole lot of factors that way. I work particularly in ADHD quite a lot and there we see that there's a number of different factors including, you know, the sort of parental styles, the fact that we're using technology much more which means we switch our attention very rapidly from, you know, looking at our phones or looking at something very quickly, short videos on our phones, and then maybe using the computer or doing something else rather than focusing our attention for long periods of time in order to get a goal done. So, you know, like homework or something really important. So that's actually probably producing a lot of problems because it's been shown in studies that if students have their phone and if they're getting messages or something on their phones during a lecture, they don't do as well as people who don't have their phones with them. And also even there's a study which shows that just having a phone, even if it's not on, sort of generates a kind of anxiety. People want to keep checking it even though it's sitting there and it's off. So there's a lot of that that's causing probably very rapid switching of attention and distraction and that of course is the type of thing that you might see in attention deficit hyperactivity disorder. Rachael - So one of the statistics that was mentioned by Rachel de Souza, the Children's Commissioner for England, was that there was almost a 50% increase since 2018-2019 in mental health problems. So do you think COVID has impacted this at all?Barbara - It definitely seems to have affected quite a few of the mental health disorders. Certainly exacerbated people who already had the symptoms, you know, got worse during that time. And obviously you can imagine how maybe obsessive compulsive disorder might have increased because everybody was worried about, you know, catching something and everybody was washing their hands and making sure that everything was, you know, clean. So that may also have effects on that. And anxiety as well because obviously a lot of people were anxious and a lot of people experienced bereavement during that period. So that would also lead to possibly to depression if you didn't have it dealt with effectively, you know. So definitely there was that. We actually did our own study where we looked at people during the COVID-19 pandemic and we did see that those people who were less socially connected actually had increased symptoms of depression in terms of negative thoughts and biases, that kind of thing. And so people really did much better if they had some kind of social connection. I've also written about a very critical group which is the one-to-five year-olds because that's the time during which social cognition develops. And if you didn't have a sibling during that time and if your parents were busy, say, trying to work from home or do something like that, and they weren't actually engaged and couldn't interact with you, but you also wouldn't have had many peers if you didn't have a sibling. They wouldn't have been, you know, developing theory of mind and the sort of sharing and cognitive processes, empathy, the types of things that you develop with social cognition during that period of time. And certainly teachers have reported that when they come into the sort of nursery and primary schools that they're sometimes slightly more aggressive and they don't want to share toys and there's a lot more problems in social interaction. Rachael - And I guess economic inequalities also play into this because for those teenagers or children that were at home during the lockdown, if they didn't have access to a good computer or the internet, then they would have also struggled to communicate with friends during the pandemic. Barbara - Yes, I'm sure that's the case. I mean, they usually do with most things. One of my favourite studies that I've done was published inPsychological Medicineand it really looked at reading for pleasure in young children. And those children, and we use the ABCD study database, which is a USA study. And what we showed is that those children who read early in life for pleasure, when they were adolescents, they had better mental health, you know, less symptoms of depression, they had less symptoms of inattention, better school attainment, better cognition, and actually better brain structure. So it's really important and I raised it because we actually looked at socio-economic status in that study. And regardless of socio-economic status, you got the benefits. So those children who read for pleasure early had all those benefits that accrued in adolescence and probably they'd keep them lifelong. So this very small intervention can be really important later on. Rachael - You mentioned this study was in America. So the statistics that have been published recently this week are for the UK. And are we seeing this increase in mental health problems in other areas of the world as well?Barbara - Yes, while I was in CIMP, I did a session with Tom Insell and I mentioned this problem of increasing mental health problems in young people. And he said basically the same was happening over in the USA. Rachael - And are we seeing this with adults as well?Barbara - Well, I've been focusing on attention deficit hyperactivity disorder, and I'm just about to publish with Christelle Langley a paper in theJournal of Psychopharmacology. And what we saw was that actually they are rising for ADHD diagnosis and prescriptions. They're rising a lot in adults as well. And the interesting thing is in 2025, that was the first time that it was actually greater prescriptions for adults than for children. So yes, it's increasing. The other interesting statistic there was we think of it as a neurodevelopmental problem, ADHD. And we know that usually there's four boys to one girl gets diagnosed. But in the adult population, it's virtually one to one. Antibodies provide protection against norovirusCraig Wilen, Yale UniversityNorovirus, which is also known as the “Winter vomiting bug”, is an illness that causes vomiting, nausea, stomach pain, and diarrhoea. It is relatively common, but highly unpleasant and contagious, with no approved vaccine or antiviral therapy. In low- and middle-income countries, it kills 200,000 people a year, and mostly young children. But a recent study identified an antibody, immunoglobulin A, that helps the immune system defend against norovirus infections. Yale University’s Craig Wilen has been telling Chris Smith about it…Craig - Yeah, so we're really interested in this virus called norovirus, which is a tiny virus that causes a big problem, which is severe vomiting and diarrhoea. It's also commonly called the cruise ship virus. And the big problem we're trying to address is how can we prevent this virus from causing disease? And ultimately, how can we make a vaccine or a drug to prevent infection and prevent these symptoms? It's a major global public health problem that no one wants. Currently, there's no solutions, there's no vaccines, and there's no drugs for it. Chris - It is a big problem, isn't it? Because I mean, if you look at an average country like the UK, it's probably millions of cases per year, most of them, most people are not aware of, because it's a 24 hour thing, isn't it? Short and sweet, but not sweet. Craig - Typically, we say that people are getting infected every three to four or five years, sometimes you don't get symptoms. But across the globe, there's probably 500 to 800 million infections every single year. There's many different types of human norovirus that cause infection. So it's ubiquitous, but poorly understood. Chris - Given that ubiquity, why don't we make a lifelong immune response to it in the same way that if I ran into measles, thankfully, I had a vaccine. But if I ran into measles and caught that, I wouldn't catch it again, probably. Why is it not like that for noro?Craig - So first is that there's many different strains of norovirus. So just like influenza, you may have protection against one strain, but a new strain may pop up in a couple of years. And this happened last year, actually, where a new strain popped up that people hadn't seen that much of before. And there were more cases than usual. The second answer is that norovirus is really smart and it infects a part of your gut called your small intestine. And here the immune system works a little bit differently. We found that there's a different type of antibody, which is this really sticky protein that acts like a wet blanket to block the virus from infecting you. And that type of antibody tends to be relatively short lived. So we think that that antibody will stick around for a bit, but then it goes away so that the body's not wasting time making this antibody that isn't needed. And we think that makes people resusceptible. Now, we do think that when people get reinfected, that they probably do get less severe disease because they previously have some protection. And this is exactly what we see with COVID. But this term sterilising immunity where you get infected once and then never again, that is just not what happens with norovirus, like many other viruses like measles or rotavirus. Chris - What are you doing then to try and realise your goal of actually making this less of an international disease burden?Craig - Yeah. So recently, a large randomised control trial of the first big human norovirus vaccine failed quite miserably. It was a multi-country study where they vaccinated thousands of infants and the vaccine had zero percent efficacy. And for us, this was really a big wake up call. And I think for the field, which is we can't make a good vaccine and spend hundreds of millions of dollars trying to get it to work if we don't actually understand infection and how we can get an effective immune response to protect us against infection. So we wanted to take a step back and ask actually, what are the mechanisms that control infection? And to do this, we used mice. It's because in mice, we could really control infection. We could control the virus, we control the animals. And here we use this to basically make a model of human norovirus and ask what are the mechanisms and what parts of the immune system are necessary and sufficient to protect us from infection? What the long-term goal is, can we now mimic this with a vaccine in a person?Chris - What does it actually do in mice then? What have we been missing in people that you can now potentially see in mice with the mouse equivalent?Craig - In humans, for many, many years, we knew that the major correlates of protection to infection were two different types of antibodies. One type of antibody called IgG, and this antibody circulates in the blood and is really easy to measure. Then there's a second antibody that tends to live in our saliva, in our secretions from our airway and nose and in our intestines. And that's a type of antibody called IgA. And typically, if you get infected, IgA and IgG kind of go hand in hand and both go up and both go down together. But we didn't know which one of those, if either, was actually essential. So much of the vaccine research was, all right, let's just come up with a vaccine that could boost this blood IgG antibody because it's easier to measure blood than it is antibodies in the faeces. But we didn't know that that was actually protective. So we actually asked which of these is essential. And it turned out that in mice, at least, only IgA was essential and IgG was not. And that was a fairly big surprise to us, given the human literature and the assumptions that we and others erroneously made over the years. Chris - IgA is a form of antibody that gets secreted at various surfaces. Like you say, it's at our airways, it's in tears, genital secretions and so on. So is the mechanism of defence against noro that you're outlining then, that the body makes this antibody and it basically splurges it all over the intestinal lining. So it's there like a barrier. So if the virus does come again, the antibody is there ready to greet it. Craig - Yeah, the really cool thing about IgA and what makes it special is that there's a little piece of IgA that is different than IgG that enables it to cross these semi-permeable barriers and cross from your blood to your intestines or to cross from your blood to your tears or nasal secretions or breast milk. And that's what makes it special. And that's what helps it fight infection in the gut before that infection can really take hold and replicate. The hard part about IgA, it's much harder to make vaccines that lead to higher IgA. It's pretty easy to make vaccines that lead to really good IgG responses. Chris - And do you think you can surmount that then?Craig - We do. We think it will take time and additional research. I think the first step that we identified is now that we know IgA is really important, we can now make this as our primary goal for a vaccine. There are several vaccine approaches that are being tested for influenza, for COVID, and for other infections that are really focused on IgA. But it is a difficult barrier to overcome. I think one thing that may work is making what's called a live attenuated vaccine, which is a weakened version of the virus. And we have this for poliovirus, we have this for rotavirus. I think that might be the most effective approach for norovirus. But there's a lot of barriers for us to overcome scientifically to be able to get there. And then there's other approaches where maybe we need new vaccine platforms that can actually lead to IgA. And we and others are working on those as well.