This week on The Naked Scientists, we’re going to take a closer look at attention deficit hyperactivity disorder - which is usually referred to by its acronym: ADHD. Globally, it’s estimated that around 5% of children and adolescents are affected by ADHD. But those numbers vary from country to country and diagnoses are on the rise....
In this episode
ADHD and me
Tania Martin & Nicola Jayne Little, Celebrate Difference
What is it actually like to live with ADHD? Nicola Jayne Little is a social entrepreneur who set up the ADHD support group 'Celebrate Difference’, and Tania Martin works with organisations around neuroinclusion. They have both recently been diagnosed with the condition.
Nicola - It's like 3 billion thoughts all at the same time and never being able to get to the end of any of them whilst tripping down the stairs and not being able to find your keys.
Chris - Do you mean as in you've got so many things you feel you want to do, need to do, have to think about, that it's hard to prioritise.
Nicola - Absolutely. And there is never a time that the thought gets to the end of the thought because all of the other thoughts have barged their way in, uninvited mostly, and knocked the thing I was thinking about in the first place. And that could be anything. It could be, 'what am I going to have for tea?' And then all of a sudden I'm painting a wall. It could be 'how am I going to do this latest project at work?' And I end up in bed playing a game. There is never a time for me where one thing smoothly leads to a conclusion.
Chris - Your experience, Tania? Same?
Tania - Yeah. Very similar. I describe it as I've got a million little trampolines in my head and thoughts bouncing off these little trampolines. And I can go in all sorts of random directions and I never really know how I sometimes end up where I end up in terms of what comes out of my mouth. And the other thing for me is that I really struggle with time and a sense of time. So I don't really understand what time means. So five minutes to me could mean an hour in real life for somebody else because I could potentially get lost in time, in terms of what I'm focused on. On that as well, if I need to be somewhere and I need to be there in five minutes, I then potentially have a challenge in terms of getting there in five minutes because as I said, time means nothing.
Chris - Is that because you get sidetracked by things and then sort of go down a rabbit hole, almost like YouTube videos where you get sucked from one thing into the next, into the next and you lose sense of time? Or is it just that you have no sense of I need to hurry, I need to be somewhere and this is how long it's going to take?
Tania - It's the latter. I have no sense of time. So if somebody says to me, I'll meet you downstairs in 10 minutes, if I don't see what the time is on a clock, I won't know how long 10 minutes has been. So it means for me that I spend a lot of time staring at a clock and staring at a diary to make sure I'm where I need to be at the right time.
Chris - Have you noticed, Nicola, we've been on this interview for an hour now and Tania hasn't noticed.
Nicola - I mean, honestly <laugh> it could be years, it could be <laugh>.
Chris - But being serious again, Nicola, when did you realise that life was not like that for everybody you're describing sort of tripping down the cognitive staircase all the time, and Tanya's got a hundred million trampolines in her head. Was that always the case? And when did you realise that that might not be the norm?
Nicola - So I remember feeling different when I was nine or 10. To feel different is my norm. And then through my teens and twenties, I knew that the way I perceived things and the way I reacted to things, whether that's at work or outside of work, wasn't quite the way I thought everybody else was doing it. I had this feeling that I was never quite getting there. I was never quite achieving my potential, but I didn't understand why. So most of my life has been 'why does this keep happening?' And I had to ask my dad, 'dad, why do I keep ending up in these situations?' And then at 45 I read something, I'd been scrolling around and somebody had put a list of problems and challenges that she'd had. And if you just took her name out and put my name in, that was my list. That was my life. She had literally summed up in a paragraph 30 years of my questions. It was the most bizarre moment of my life.
Chris - Tania, did anyone hold up a mirror to you like that and say, this is the symptoms and you immediately recognised yourself? Or was your experience different?
Tania - I actually found out about my own ADHD when I was upskilling myself in my role. So I was having to learn about neurodiversity, which is that broad umbrella term that includes ADHD, autism, dyslexia, dyspraxia, et cetera. And when I was doing it, I was going down the list and I was like, tick, tick, tick, tick. That's me. It was like a bit of a light bulb moment for me. And I've also known for most of my life that there's been something that hasn't quite fitted. And in fact, I was actually diagnosed with anxiety and depression at the age of 13 and I have spent my whole life trying to fix that anxiety and depression because as I mentioned, I have a lot of thoughts. If those thoughts aren't good thoughts that can then manifest itself in potentially anxious and not so happy circumstances. So the ADHD diagnosis for me was a light bulb moment that shone a light on why I have struggled, as Nicola said, to fit in, you feel different. So I've worked in corporate for 20 years and I always felt like it didn't quite fit. Diagnosis gave me that sense as to why that was.
Chris - And Nicola, why did you decide to actually formalise your diagnosis? You read that list and you thought, yeah, that's me. A lot of adults would probably have said, 'well, that explains a few things, but life goes on.' So why did you actually decide to go and make this formal
Nicola - For me to get a diagnosis that gives me an explanation and a reason, not excuses but an explanation, and a reason for why my patterns of behaviour as they are gives me half a chance to do something about that. But if you're always guessing or never quite certain, for me, and this is probably my autistic self, I can't see how you can do anything positive with that. I had to have my diagnosis because until it was rubber stamped and someone told me, for sure it wasn't, or it may not be real.
07:37 - What is ADHD?
What is ADHD?
Jo Steer, Achieving for Children
What exactly do we know about ADHD? Here’s Jo Steer, a consultant clinical psychologist and author of 'My Unique ADHD World' and editor of Understanding ADHD in Girls & Women...
Jo - So we are really talking about 5% of the population that we think have ADHD, so attention deficit hyperactivity disorder. It can vary across countries, which is interesting in terms of where it's being identified more. And if we look more to America, the rates are more like 10%, but in the UK it's around 5% of the population.
Chris - And if we consider children and adults separately, is it the same 5%? Do you have this as a child and turn into an adult with it or do we get some children who it goes away and some adults who are newly diagnosed or both?
Jo - Broadly speaking, we talk about ADHD as a neurodevelopmental condition or disorder. And what that means is it's lifelong, and it impacts on your brain. It's the way your brain functions. And this means that if you are a child and you are identified as having ADHD, you're very likely to continue to have that into adulthood. It might look differently and impact differently in your adult life or even throughout your childhood. Those symptoms can shift and change slightly depending on the demands that are being made on you, but also depending on the support that's around to help you with the difficulties you struggle with. So it can look different at different points. It's really important to remember that. And what's also of note is that we're finding more and more adults are now coming forward and identifying that they need an assessment for ADHD and they weren't identified in childhood and potentially they have had those difficulties all the way through their life. That's part of the criteria. We need to see evidence that these difficulties were there before the age of 12 years. And many of these adults can tell us in lots of detail that they've had lifelong concerns around attention and hyperactivity and impulsivity, but they're only now coming forward for an assessment. Perhaps just learning about ADHD for the first time or feeling confident enough to ask for that assessment even though they might have actually been struggling throughout the whole of their childhood adolescence and into their adult lives.
Chris - Do we know anything about risk factors? Is it more common in families? Is one gender more likely to have this than the other? What do we know about that aspect?
Jo - Definitely know that it runs in families. We do see a genetic link. So we do see children whose parents have symptoms, perhaps they may not have been diagnosed, but certainly have some of the symptoms or even families where more than one sibling have the difficulties. Sometimes, it might not be the immediate family that all have ADHD or a number of people have ADHD, but a more extended family. So if you look out to cousins or aunties and uncles. But it is really common and it's definitely a risk factor that someone in the family may be neurodiverse and have ADHD. However, there are also times when I assess children and adults and they come and they can't identify anybody within their family that has similar difficulties whether they've been diagnosed or not. So it's not a given. And I always say to young people and adults that just because you have ADHD doesn't mean that you will go on to have a child who has ADHD, but it does increase the risk, absolutely. There can be other factors that increase the risk as well, but nothing is causal. So there isn't one thing that we know if this happens, this definitely causes ADHD. So children that are born prematurely, babies that are born prematurely have an increased risk of ADHD, but not all babies that are born prematurely will have ADHD. So there are factors like that that can play into the situation but are not causal.
Chris - What about imaging studies? If we put people in brain scanners, does anything leap out?
Jo - We do know that there are differences in the brains of people who have ADHD and people who don't. And those differences can be in the structure of the brain as well as the neurochemistry of the brain. Now what's really interesting is at the moment where we're at, we can't pop someone in a brain scanner and do the neuroimaging and say, 'right, we can see you've got ADHD.' So it's not visible on an individual basis. But when we analyse groups, so a group of people who have ADHD and their brain scans and a group of people who don't, that's when those differences do show up. I hope in years to come, we may progress and find that we are able to use those brain scanners to help us identify these differences more clearly on an individual basis. But what we're seeing is we know that there are some key neurotransmitters and what a neurotransmitter is, is the body's chemical in the brain that helps us move messages around our brain. And there are two key neurotransmitters that we know are implicated within ADHD. So one of them is called dopamine and the other one is called noradrenaline. And we know both of those are what we might call dysregulated or different in the brain of people who have ADHD.
Chris - To what extent is this something that a person grows into? Because obviously we know the more we do something, the better our brains become at doing that thing. So is it that an environment pushes an individual to develop in a certain way and then they develop these traits that you are seeing behaviourally, but also on brain scans? And in fact, if they developed in a different environment, that wouldn't happen?
Jo - So the research tells us that people are born with their brains in this way. And, as much as our brains can be moldable and have some neuroplasticity to them so that they can change, actually we can't change them by doing more of something to make those neurotransmitters work differently. They do work differently. And the only way to support that change is possibly through medication or through learning different strategies to, get round or hijack some of the, the challenges that someone might have. So we might call them a toolbox or techniques that people use to adjust their life so that they can manage the difficulties in a different way. But you can't train the brain to not have ADHD
Chris - To what extent, though, is a person with ADHD a normal person, and what we've done is to medicalise an extreme of normality. Because if we think about the population as a range of different traits and personalities and behaviours and, and characteristics, and there are always extremes in a normal range. And some people might be at one end of that range. And are we not in danger of giving people a label when there isn't anything wrong with them, it's just the way they are?
Jo - I think that's a really important question and a really hot topic. Absolutely. And I think one of the things that's really important to remember about ADHD is that you need to go for an assessment with a qualified medical professional to be diagnosed with ADHD. And part of that process is to assess and understand the impact of the difficulties on somebody's life. So the impact on school, the impact on home or in the workplace, depending on where someone's at in their lifetime really. And there has to be a significant impact of their symptoms, of inattention, hyperactivity, and impulsivity on their daily living. And that's part of the criteria to meet the threshold for an ADHD diagnosis.
16:39 - Why are ADHD referrals rising?
Why are ADHD referrals rising?
Thea Stein, Nuffield Trust
The only way to find out if you have ADHD is to get a diagnosis. But there has been a huge uptick in referrals in many nations, with one prominent health think-tank here in the UK saying that demand has overtaken the capacity to meet it. Thea Stein is the chief executive of the Nuffield Trust…
Thea - One of the first things I asked the organisation to look at when I arrived was actually statistics around ADHD and autism because I was really aware, having come from a job where for nine years I was leading the services for children around diagnosis for autism and ADHD, what a significant issue it was. And I felt that the facts and figures weren't out there in the public domain as clearly as the figures, for example, for waiting for surgery, and I wanted us to do some work.
Chris - What did the figures for children show? And we should also emphasise this is not just a problem of children, is it? We know that a lot of adults, almost certainly children, turn into adults who have ADHD, but some adults are newly diagnosed as well. So what is the scale of the problem?
Thea - Well, interestingly, the data isn't collected at a national level in terms of the waiting list data. So whilst I've got really good waiting list data for assessment for autism, there actually isn't a similar figure for ADHD. What we did though was use a proxy, something to help us understand that, which was prescribing data for ADHD medication and what we could see there between 2019/20 to 2022/23. So those years between that, we had a 51% increase in the prescription medication for ADHD. So we know that something is going on by looking at that because a lot of people, children and adults who have ADHD do get a prescription for medication. And so we thought by looking at that, it would give us some idea of the scale of what was happening. We also know through a petitions committee that there are a lot of people who are waiting really, really long periods of time, and at least 10% of adults and children are waiting between two and three years. Final fact, which I think is really interesting, is that the biggest increase in patients getting the prescription medications for ADHD are between 25 and 44, and the biggest increase in that group is between 30 and 34. So yeah, there's a lot going on.
19:19 - How is ADHD treated?
How is ADHD treated?
Nicola Jayne Little & Tania Martin & Barbara Sahakian, University of Cambridge
The number of people being prescribed ADHD medication has been used to determine the extent of the condition. It doesn’t, of course, tell the whole story. But how does the medication affect people who take it? Here’s Nicola Jayne Little and Tania Martin again…
Tania - If I'm really honest with you, one of the reasons why I wanted to gain a diagnosis was because I wanted to try medication. For most of my life, I've been in these bouts of depression and anxiety and I wanted something to fix my brain. I went to my GP, had a conversation with her, she was incredibly supportive. I got a diagnosis quite quickly after that.
Chris - And you mentioned managing your symptoms and wanting to try medication. What did you use?
Tania - So I actually didn't get on with it very well, so I tried both stimulant and non-stimulant medications. And unfortunately I'm not medicated now because whilst they helped some of the symptoms, they made other symptoms worse for me personally.
Chris - Was that your experience, Nicola, or have you just gone down the behavioural route knowing the problem and grappling with it that way?
Nicola - Oh no. I'm fully medicated up to my eyeballs. It's the best decision I ever made to try stimulants, you know, and for someone with ADHD, and again, the narrative is really misunderstood, a stimulant for me that might stimulate someone else to make them high, I suppose is the term. For me, the stimulants let me think in a straight line. So instead of the plate of mad spaghetti that I can never get control of, I have a better opportunity to start a thought and get to the end of the thought, to start a task and get to the end of a task to be able to rationalise in a different way. The meds for me have changed my life in a positive way. That's not to say I always wanted to take them or wanted to take them, but in doing so, has fundamentally changed my life.
That was Nicola Jayne Little and, before that, Tania Martin. I caught up with Barbara Sahakian, professor of clinical psychology at the University of Cambridge, to discuss what types of treatments people with ADHD are currently prescribed…
Barbara - Methylphenidate, it's also known as Ritalin is one of the most effective treatments for ADHD. And it is really the first line treatment that is offered to people if you have moderate to severe symptoms. Obviously if your symptoms are mild, they can be managed with more psychological treatments such as cognitive behavioural treatments and sort of structuring your activities and helping you plan and that sort of thing. But if it's more moderate to severe, you may need drug treatment. And then methylphenidate is usually the first choice.
Chris - What sort of a difference does that make? Do we have any quantitative or objective numbers we can put on this?
Barbara - Well, it's been said to be about 70% effective, and it seems to work for most people. But of course, no drugs work for everybody. And some people may have comorbidities, which means that they might have anxiety or depression along with the ADHD. And that may be that the drug doesn't work quite so well in some other groups with these comorbidities.
Chris - What do we understand about what the drug is actually doing in the brain of someone with ADHD to get them that benefit?
Barbara - So the chemicals in the brain, dopamine and noradrenaline, are both increased by methylphenidate. And what happens is their re-uptake is actually blocked. So there's more in the synaptic cleft. So that basically boosts dopamine and noradrenaline in the brain.
Chris - Do people who have ADHD have a deficit in those chemicals to start with, or is there something else wrong and boosting the levels up helps to solve another problem?
Barbara - Well, what we do know is there can be changes in the brains of people with ADHD and actually when they're on drugs chronically like methylphenidate, especially if they're children, when they start these drugs, they can actually mitigate the effects that you see in the brains. So they do do that, but we do know that methylphenidate is what we might call a cognitive enhancing drug. So for anybody who has some problems with attention, it will improve attention. Or for impulsivity it will do that as well. So it is a sort of general cognitive enhancer. And in our study that we published in Brain with Natalia Del Campo and other people, we showed that the drug is not actually acting in a different way in the brain of people with ADHD. It's the same as it would in a control group of people without ADHD. That's part of the issue because people have been suspicious sometimes. And the Care Quality Commission has said the reason for increases in prescription is because ADHD is being identified and diagnosed more in children, which is good. And now in adults too, which is also good, but there may also be circumstances where people are using it more as a cognitive enhancing drug and perhaps don't really need the drug, but want to use it because it helps with their attention as well, and other issues.
Chris - Nicola said that it helped her quite a bit. Tania on the other hand said she just couldn't get on with it. Is that normal?
Barbara - Well, there'll always be some people that the drug doesn't work for. I mean, I think the first person benefited from it and most people will benefit from it. But if you have some comorbidities, for instance, one of the side effects, sometimes people can get a bit more nervous and so if you've got anxiety, it may exacerbate that, for instance. And there's other conditions where if you have a sort of bipolar disorder it might exacerbate your mania, for instance. So you have to be careful when there's comorbidity involved. But in somebody who has only the ADHD disorder, then it should work out reasonably well for treatment.
Chris - One of the paradoxes about this is that people with ADHD struggle to stay on task and focused on doing one thing. They want to be onto the next thing before they finish the first thing. And the drugs that we're exploring to try to help them are actually sometimes abused because people want more energy and want to be more impulsive. And it seems a bit weird that we treat a condition of impulsivity with a drug that can make people impulsive.
Barbara - Yeah, I mean, I first started to study the drug because I was fascinated by the fact why would you give a stimulant drug to somebody who was hyperactive? But actually the evidence is that it helps control the behaviour. And there is this idea that there's an inverted U shape function with the arousal level. So that if you are under aroused, the drug will bring you out to an optimal level of arousal. If you're over aroused, it will bring you down again. So it may well be that it's working to get the right optimal level of arousal for whatever your behavioural circumstances might be or your cognitive circumstances, as the case is in schools and universities.
Chris - Do you think there's a difference in terms of outcomes and benefits and long-term effects, whether you are an adult who starts taking these drugs versus a child? Because as we've heard in recent weeks with people arguing about the trans debates and so on that are going on, the brain is still developing well into your twenties. And if you are taking a chemical that chronically alters the levels of various nerve transmitter chemicals in the brain, is there a danger you're in some way bending someone's brain from a young age permanently and that could have unforeseen consequences?
Barbara - Well that's why you have to be careful. You know, students often use it as a study drug, and I'm always concerned about that because if they basically don't need the drug, they don't have a diagnosis of ADHD, but they just want to use it to cognitively enhance themselves and help the study or stay awake longer.
Chris - Is that actually common though, Barbara? Are lots of people doing that?
Barbara - Certainly at universities, yeah. There's quite a percentage of people that do it. And actually it's not just university. I mean there's quite a lot of data where they've looked at surveys and they found that these drugs are used quite commonly for cognitive enhancing drugs. Actually, the most common one used in the UK is modafinil, but in the USA, they're more likely to use stimulants like Adderall or Ritalin.
Chris - And you were going to go on and tell us about what happens if you do use this from a young age without a diagnosis or even with a diagnosis of ADHD.
Barbara - Yeah, so I think that we do have evidence that there are differences in the brains of people with ADHD and that some of these differences seem to be mitigated with the use of the drug. So that could actually be beneficial. It may be that it's actually helping you get back on track as far as that goes. But I would think that if your brain is developing within the typical trajectory of normal and no problems, then introducing a drug may not be advantageous for you. And especially while your brains are still in development up until about the age of 24, 25.
The latest ADHD research
Ellie Dommett, King's College London
What are the new and innovative ways that scientists have found to help people with ADHD? Ellie Dommett is a professor of neuroscience at King's College London, where she leads the ADHD research lab…
Ellie - Certainly researchers are looking quite carefully at different types of exercise. We know from our own research that individuals with ADHD often end up exercising as a way that they recognise is self-managing their symptoms. So not necessarily on the guidance of a healthcare professional, sometimes it's before they've managed to get a diagnosis, so they really interact with healthcare professionals, but they're working out that exercise can help them manage life better and manage their symptoms better. So exercise is starting to show a reasonable amount of evidence for being beneficial and it's beneficial to everybody. So it's not just that you'll only attend more if you have ADHD once you've exercised. It appears that exercise is just generally good for lots of mental functions. Those with ADHD are no different. So exercise is helpful. Changes in diet have been looked at in various different ways. So there's no recommendation, for example, to do things like remove food colorings, which is an area that has received quite a lot of media coverage previously, or to cut out all sugar or anything like that. Actually, the evidence in this area is much weaker than it is for exercise. So by weaker evidence, I don't mean that we don't think diet is helpful or as helpful, but rather we don't yet have enough evidence to make a solid conclusion. The longest study that's looked at diet has examined something called the few foods diets. So that's where you sort of remove lots of food and then gradually reintroduce them and examine what happens to symptoms. And that's probably the one that's received the most attention, but it is also only showing very small effects. So whilst it could be beneficial, those effects are quite small. As well as looking at diet and exercise, there is research looking into things like mindfulness. Mindfulness has been very popular, not just for conditions like ADHD. It's very popular for just general wellbeing. So not because you feel that you need to remove symptoms of a condition like depression and anxiety, but rather just because it's a nice practice to get a better sense of wellbeing. And mindfulness studies into ADHD have seen some improvements. One of the challenges to all treatments for ADHD is that ADHD rarely occurs by itself. It's a condition that is often co-occurring, or comorbid to use the medical term, co-occurring with other conditions. And in adults it's particularly common, for example, to see ADHD alongside depression or anxiety or both of these. Now, mindfulness may be beneficial, but what we are not clear on yet is, is it beneficial to ADHD or does it reduce some of the symptoms of depression and anxiety? So the person feels better even though their ADHD symptoms have remained. So there's various lifestyle approaches that are being taken to look at how we could improve the experiences of somebody with ADHD. And then there's also behavioural-type treatments that are more novel and innovative. So ones that are not yet currently recommended, but people are looking at in research. So we're doing some work, for example, on eye movement training and whether that could be beneficial to individuals with ADHD. And we're particularly looking at adults. So there's a range of different approaches that are being investigated. And that's a really important thing because when a condition is as diverse as ADHD, you will not get a one size fits all solution.
Chris - How might the way you move your eyes affect your ADHD experience?
Ellie - So the hypothesis that we are working with, and it is very much still a hypothesis, which means we're trying to test this idea out. So we haven't got definitive proof. But our hypothesis relates to the fact that we produce tiny eye movements all the time. And these are ones that we're not even aware we're making. And when we make those eye movements, they're called microsaccades. They're very, very tiny. Those eye movements are controlled by a very small region in the middle of the brain called the superior colliculus. And the superior colliculus is responsible for controlling those eye movements and the movements correlate very strongly with symptoms of ADHD. And the superior colliculus itself has been implicated in the brain basis of ADHD in a range of studies. What's interesting and what offers the possibility of a treatment or intervention is that eye movements can be trained. So we know that by doing various tasks to control where we look with our eyes, we can alter the movements that we make. And in order to make that alteration, of course we're actually altering the brain activity in the area that controls the movements. So if we can control our eye movements by altering activity in that area and that area is also responsible for some of the symptoms of the ADHD, then that may in turn improve the symptoms. So this is a very experimental idea, but it just demonstrates this need to look outside of traditional medication treatments for ADHD and also recognises the fact that we still don't have a brilliant understanding of what's changing in the brain with ADHD. So we need to be constantly exploring possibilities.
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