Unpacking ADHD

We take a close look at attention deficit hyperactivity disorder
18 May 2021
Presented by Chris Smith, Adam Murphy
Production by Adam Murphy.


 an image of a brain made of jigsaw pieces


This week, we're discussing ADHD: attention deficit hyperactivity disorder. It can lead to difficulty concentrating and focusing on tasks, and many adults don’t actually realise they have it. So what is it, and what can we do to help people who have it? Plus, news of the Indian variant of Covid-19, new discoveries from the 40 year old Voyager 1 probe, and bats made from bamboo - but is that cricket?

In this episode

cartoon image of person holding a stay at home sign

01:05 - Indian Covid-19 variant spreading in the UK

A subtype of the Indian coronavirus variant picked up in the UK could derail the roadmap for easing lockdown

Indian Covid-19 variant spreading in the UK
Christina Pagel, University College London

One of the Indian coronavirus variants that’s been picked up in the UK is threatening to derail the roadmap for easing lockdown. As the Prime Minister Boris Johnson has highlighted, "it has been spreading",  and what’s got the government’s scientific advisory group - SAGE - worried is that this variant, which is known as “subtype 2” - or B 1.617.2 - is spreading within the community in the UK three times faster than other imported strains like the South Africa or Brazilian variants. This suggests it has some kind of enhanced transmissibility, which could strike out one of the government’s 4 tests that need to be fulfilled to proceed with re-opening the country. But, the quandary is that the total number of cases here is - at the moment - still relatively small, and the outbreaks have - so far - been confined mainly to specific parts of the country. So does this mean we’re off the hook? And how should we proceed? Christina Pagel is a mathematician at UCL and she’s been looking at the numbers…

Christina - There are two main sources of information. The first one is the UK COVID genetics consortium. They sequence positive samples from about half of the positive cases that we get to try and work out what variant each positive case is. They show that there are now been over 1,300 cases of the new variant of concern. The one that's called B1617.2. And it's basically been doubling every week since the end of March. There's another source called Sanger, the Wellcome Sanger Institute. And what they do is use the same data, but take out all travellers and take out search testing. So what they're trying to do is see how widespread is it in the community? And they're getting 500 cases in England in the community, also doubling every week

Chris - And distribution wise, where are these cases happening?

Christina - So they're concentrated at the moment in London and the Northwest, where Sanger estimates that about 20% of current cases there are this new variant and then also in the east of England where it's about 50% of cases. And there particularly it's Bedford and in the Northwest it's Bolton, Blackburn and Sefton.

Chris - And in terms of how well this variant can spread, because that's a critical question, isn't it? Because one argument the government have made in the past when considering variants is that they don't appear to have the same reproductive advantage that our existing strains of coronavirus do, and therefore they're unlikely to gain a toehold. How does this one weigh up against the dominant strain, the Kent variant we have in the UK at the moment?

Christina - Yeah, so you're absolutely right, but the other variants, they don't seem to have been able to compete against our Kent variant, which has been the most transmissible variance so far globally, but this new one, one of the reasons they made it a variant of concern is because it does seem to be at least as transmissible, as that's what Public Health England say, WHO today also made it a variant of concern globally, because they're worried about transmissibility. Because what's happened is that in India, it seems as if this new variant is outcompeting the Kent variant. So that kind of implies that it is fitter and we're seeing it gaining ground in England, also against our dominant Kent variant.

Chris - And are you comfortable, having looked at the numbers, that this is genuinely comparing apples with apples? Or is it because we're going after this variant and we're looking for it so we're skewing the data and making it look like it's spreading more.

Christina - I am worried because you're seeing very similar patterns in other countries and you are seeing that it is definitely increasing in the community in a way that the other variants haven't managed to do. So clearly there has been a difference between this variant and the other variants, which can't, I think be just explained by testing.

Chris - Do we have any insights into who is catching it? And specifically, is it people who have already tested positive for coronavirus? And where going with that is, one of the other questions we've seen emerging both in Brazil, in their outbreak, different variants admittedly, but also India, people appear to be being infected again with this new variant. Is there evidence that that's happening here?

Christina - So this is the million dollar question, at the moment there just isn't any evidence. There's a lot of anecdotal stories, but lots of them are from India, people getting reinfected or getting infected after one dose of vaccination. But we don't know what variant they'd been infected with because typically they don't sequence cases out there. The one thing we do know from Public Health England is that there was a care home that had an outbreak of this variant, the new variant where 14 residents got infected with COVID, some of whom had symptoms and some of whom went to hospital after two doses of AstraZeneca, but none of them were severely ill and all of them recovered. So that kind of, to me implies it is possible that maybe it can affect people easier. It's not proof

Chris - The government must be finding themselves in a difficult position, mustn't they? Because on the one hand they are announcing we're on track. We're doing well for reopening and easing many of the measures on the 17th of May and onward. Yet at the same time, one of the tests that have been set out to decide whether or not we should do that includes whether or not there are variants that are concerning us. So we're just on the cusp of opening things up again when we see this popping up on our radar and it seems to be something that's moving in a worrying direction.

Christina - Yeah. And it is difficult because tests one to three, based on vaccine roll out of vaccine to sufficiently end hospitalizations have all met, you know, that's all going really well. But to me, I personally don't think that the fourth test has been met. I think there are, there is now a variant that is concerning in its growth, but yeah, it's kind of, you know, do you think that the public health measures are enough to contain it? And if they are, then it probably is safe to open on Monday, but if they're not enough, then it probably isn't. And I don't know the answer to that. So I'm assuming that the government has confidence that the measures it has in place is enough to contain these outbreaks

A large astronomical telescope against a dark starry sky.

Voyager 1 scans interstellar space
Stella Ocker, Cornell University

This week Adam Murphy spoke to Stella Ocker from Cornell University, who has been looking into new discoveries, published in Nature Astronomy, from a 40 year old probe, as Voyager 1 makes its way through interstellar space...

Adam - In 2012, the probe Voyager One passed beyond our solar system and into the emptiness of interstellar space. Except even interstellar space isn't empty, not quite. There's a very tenuous plasma surrounding our solar system, which is like a gas that's had all its electrons separated from its atoms. The stuff is called the interstellar medium. And to put it in perspective, air at sea level has more than a billion billion particles in every milliliter. In the interstellar medium that Voyager's swimming in, there's about one particle in every 10 litres, if my math is correct. We've been able to see big disruptions before in this stellar soup, but it's only now that we've managed to pick up the low underlying signal of the space between stars.

Stella - I had spent so long looking at these data that I had come to the point where I really wasn't expecting to find anything new. And then to kind of suddenly notice this, this really faint signal was almost a breath of relief that I hadn't wasted the past few months of my life.

Adam - That's Stella Ocker from Cornell University who spotted the signal. But getting new science from a probe launched in the seventies is a big ask and spotting it is no mean feat. So what is the signal? What is Voyager actually detecting?

Stella - Because a plasma consists of both electrons and protons. It's usually found in charge neutrality. The positive charges of the protons kind of cancel out the negative charges of the electrons. But if you have something perturb the plasma and cause the electrons to become displaced, then you end up setting up an electric field between the electrons and protons that tries to bring them back together and restore the plasma to charge neutrality. And so the electrons essentially try to come back from where they've been displaced and in doing so, they essentially vibrate. And so what you see is that the plasma vibrates in response to this displacement of the electrons and those vibrations are what we can detect using Voyager One.

Adam - Which means that really all Voyager needs to pick this up is a really good antenna, and someone willing to comb through all that data. But Voyager entered the interstellar medium in 2012 and the signal was only first spotted in 2017. So there was a while there where we didn't see this little hum of the interstellar medium, but that doesn't mean there was nothing.

Stella - Before we detected this really faint persistent vibration of interstellar plasma, we had been seeing these bright plasma oscillation events. These are very massive vibrations that are triggered by solar activity like flares or coronal mass ejections. And those really massive vibrations only last a short period of time. And so we saw those roughly once a year since Voyager One entered the interstellar medium. But we're not entirely sure why we've only just started to pick up this really faint persistent vibration.

Adam - And this isn't just for fun. It gives us a lot of new data as to the structure of the galaxy we live in.

Stella - So by measuring the frequency of these really faint vibrations, we can infer the density of interstellar space. And because these vibrations persist over such a long stretch of time, we can achieve an almost continuous measurement of the density over the entire three-year period we've found to the signal. So that means we can measure the density now over a straight stretch of space that's equivalent to about 10 times the distance between the earth and the sun. And that's the most complete map of the interstellar density that we've had to date. And the reason why that's useful is because knowing how the density behaves tells us about how plasma is distributed outside of our heliosphere. And it tells us what the structure of the interstellar medium actually is in our sun's local interstellar environment.

Adam - And more than that, these faint kinds of specific signals can sometimes be seen in our own atmosphere. So it might help us understand our own planet a little better. And it's pretty exceptional and pretty cool what a 40 year old probe can still do.

Stella - I think for me, the main message is that Voyager One continues to make new discoveries, even from 14 billion miles away

Artist's impression of red blood cells

13:60 - Intestinal breathing success during hypoxia

New technique to save patients in respiratory failure using the rectum to 'breathe' is a great success in pigs

Intestinal breathing success during hypoxia
Takanori Takebe, Tokyo Medical and Dental University and Cincinnati Children's Hospital

One of the many lessons we learned from the COVID 19 pandemic is the importance of having sufficient ventilators and other breathing aids to save the lives of people in hypoxic respiratory failure - where they are not getting enough oxygen into their blood to survive. Now, a group of scientists have taken inspiration from the aquatic world of sea cucumbers, freshwater fish called loaches, and the so called bum-breathing turtles, to develop a new approach. Termed ‘Enteral ventilation via anus’, the technique uses either a steady oxygen flow or the injection of a highly-oxygenated liquid into the anus, with remarkable, life-saving results in mice, rats, and even pigs. Takanori Takebe of Tokyo Medical and Dental University and Cincinnati Children’s Hospital, and lead author on the study, spoke to Eva Higginbotham…

Eva - Although it might seem strange to us, breathing through your backside has some advantages for the animals that do it. For example, the Fitzroy River turtle in Australia, sometimes affectionately called the bum breathing turtle, can stay underwater for up to three weeks at a time, thanks to this ability. And thanks to new research out of Tokyo's Medical and Dental University and Cincinnati's Children's Hospital, intestinal breathing might soon be something we humans are getting comfortable with.

Takanori - We started looking more carefully about the interanus application of oxygen, which turned out to be very effective.

Eva - That's Takanori Takebe. He and his team have devised two new approaches for getting oxygen into the blood of mice, rats, and pigs, and both take advantage of the fact that the mammalian rectum, that's the last bit of the large intestine before the anus, is both supplied with loads of blood vessels and has a fairly permeable membrane for gases to cross over, making it an excellent part of the body to adapt as another site to breathe from.

Takanori - One is a very intuitive approach we just intubated, from the anus, just to provide oxygen gas continuously. This oxygen delivery is really able to persist survival in lethal conditions. Even up to 60 minutes or even longer.

Eva - 60 minutes of breathing through the rectum just by pumping in oxygen. Sounds amazing, but also like you could get a bit uncomfortable. The more clinically relevant approach uses a liquid that's very good at dissolving oxygen, perfluorocarbon or PFC. This liquid is already used by doctors during some ice surgeries and sometimes as a type of synthetic blood for transfusions. So we already know that it's safe for humans.

Takanori - So that liquid ventilation approach is also having greater impacts on oxygenation. So as to really rescue those fatal hypoxic conditions in the mouse, rats, and pig model system.

Eva - Incredibly, Takanori showed that when just less than a pint of this PFC was injected into the anus of pigs, they would stay happily oxygenated for up to 20 minutes when in respiratory failure. And they didn't stop there, by re-injecting every 20 minutes or so they could keep the pigs going for hours, or even more. Importantly though, when we breathe in and out using our lungs, we aren't just taking in oxygen. We're getting rid of carbon dioxide and other waste products too.

Takanori - Throughout the experiments. We are quite surprised to see that carbon dioxide is actually eliminated from the body. So this observation is supporting the idea that oxygen is sucked up into the circulatory system. And whereas carbon dioxide is eliminated from the body as if perfluorocarbon is working as a breathing or gas exchange in the rectrum regions.

Eva - Takanori imagines that this new technology could be life-saving if deployed in ambulances for people being rushed to hospital, unable to breathe, or in hospitals for COVID patients who require extra oxygen or where there are limited mechanical ventilators. And he's also been approached by some other characters.

Takanori - Yeah. We actually had a discussion with an astronaut yesterday, and he is really excited to apply to space applications, particularly in emergency conditions. So there are a number of potential scenarios. We can envision the application of the intestine breathing approach, not just for medicine, but also for more broader context. So that was really exciting to me

Eva - Who knows, perhaps in the future, you'll be scuba diving without a gas canister to lug around with you. And instead with a more subtle breathing apparatus to keep you going.

A brain-computer interface detects patterns of nerve activity in the motor cortex and interprets them as handwritten letters

18:24 - Paralysed man writes again

A new system pioneered in America helped a paralysed person to "write" again for the first time in a decade...

Paralysed man writes again
Francis Willett, Stanford University

A new system pioneered in America has helped a paralysed patient to "write" again for the first time in a decade. He's able to do it at the rate of 90 characters a minute, roughly the time it takes you or me to tap out text messages, so it's pretty slick. The system works by eavesdropping on the neurological "chatter" that goes on in the brain's motor centre, which fires up when a person makes movements. The neurological signals produced here have specific patterns of activity that correspond to the pattern or shape of a movement a person intends to make. So when you write a letter or number, this involves a specific sequence of movements, so it's represented by a specific sequence of nerve impulses. And even though a person is paralysed and cannot transmit those signals to their muscles, the signals are still there, so if you pick them up and teach a computer to recognise them, you can get that person writing again - albeit on a screen - which is what Frank Willett and his team at Stanford University has managed to achieve…

Frank - This is really about trying to restore communication to people with severe paralysis, or people who are locked in. So imagine if you can't move any part of your body, how do you communicate your thoughts? And this is about making a device to let people do that.

Chris - We have made some forays in that direction though, haven't we? People have recorded brain activity and used a computer to decode that and turn it into movement.

Frank - Yep. One of the biggest ways previously, was to enable control of a computer cursor. So someone could use a brain computer interface to move a cursor around the screen and click on individual keys on an onscreen keyboard and type things out that way.

Chris - So what have you done that's different?

Frank - So what's different here is handwriting. So to use the brain computer interface, the person tries to make their hand write each individual letter that they want to type. And it turns out that this method lets us go twice as fast as previous work.

Chris - How did you do it?

Frank - It starts with recording the signals. We have two tiny sensors about the size of a baby aspirin that get placed on the outer layer of the brain, and a brain area that deals with motor control of the hand. And these sensors pick up electrical impulses from individual neurons. And then we translate these impulses into text. So when he tries to write each letter, that evokes a specific pattern of impulses across the different neurons, and we detect that and figure out what he's trying to write and type it on the screen.

Chris - How do you figure out what letter they are trying to write? Is that, you basically say, right, I want you to imagine writing a letter A or letter B, and you do this enough times, the computer therefore can learn when the person tries to do an a, this is the pattern of activity that that bit of the brain generates?

Frank - Exactly. It's a pattern recognition problem. And that was one of the main challenges in this work was trying to make an algorithm that was accurate enough to, you know, reliably tell from these electrical impulses, exactly what letter you're trying to write, because we don't have the luxury of recording from every neuron and motor areas of the brain. We can only record from a handful. These neurons are variable and we call them noisy. Like they don't always have a clear signal. So we have to see through that noise and be able to reliably pick out what the letters are.

Chris - I've got a copy of your paper in front of me. And you've presented in that paper, a facsimile of what the "writing" in inverted commas that the person produces looks like. It's stunning.

Frank - Thanks. Yeah. We were excited and surprised that, you know, even after 10 years of paralysis, so he hasn't written or moved his hand after 10 years, still the brain activity in the motor areas of the brain still has this very fine structure where we could even figure out, you know, where his imaginary pen is trying to move and what these letters look like.

Chris - How accurate is your system though? Because obviously if you want to extrapolate this, so a person can write notes and write things down for people quickly in this way, if they're trying to write the word ship, they don't want to make a spelling error there, do they? So how accurate is it?

Frank - It's quite accurate. And that's one of the exciting things about it, is that we think it might actually be usable in the real world. The raw accuracy before you apply any kind of auto correction type of system is about 95%. So one out of every 20 letters is wrong, but if you use modern auto correction techniques, like on your smartphone, we found that when we applied that the accuracy was above 99%.

Chris - And if the person starts to actually write whole sentences, because when you just formulate one letter in your mind's eye, that's just one sequence of movements. But often when you write a series of letters, you'd think about joining them up and then joining words into sentences. Does that not blur the movement signals and does that not make the machine make more mistakes?

Frank - Yeah, well, that's definitely a part of a challenging problem, is these transitions between the letters. We actually asked the participant to write as if you were writing on a palm pilot, actually. So to write in print, not in cursive and write each letter on top of the previous one.

Chris - And how did the patient actually respond to this?

Frank - Well, I think compared to a lot of things, it was pretty easy to use. So one exciting part of this was that even on the first day, when we asked him to try to write letters, we got beautiful neural activity back, that was highly interpretable. So we didn't have to like, train up to use this over a long period of time.

Chris - I presume your patient's right-handed?

Frank - Yes.

Chris - Because 90% of the population are. So I had a 90% chance of saying that correctly, but have you tried swapping around to the other hand, can you, for the first time in your life, write neatly with the wrong hand as it were with your system potentially?

Frank - Well, yeah, it's interesting because the left side of the brain actually controls the right side of the body and vice versa. So these implants were placed into the left side of his brain and we have him use his right hand to use the system. But actually we found that contrary to what you might think, this brain area does encode both of the hands. So we can actually ask him to do things with his left hand and pick up activity as well, but it's not quite as strong.

Chris - And if he gesticulates in his mind's eye as he's writing, does that totally confuse your system?

Frank - Yeah. Yeah. We haven't made the system robust, to be able to use any hand or anything. We've only focused on the right hand so that probably wouldn't go well.


A cartoon of a cricket bat and cricket ball

25:28 - Cricket bats made from bamboo

Willow's had a good innings, but is bamboo about to be a hit?

Cricket bats made from bamboo
Ben Tinkler-Davies

For cricket lovers, there’s nothing more satisfying than the sound of leather on willow. But scientists say the sport should be swapping out its willow bats…for bamboo! Ben Tinkler-Davies from the University of Cambridge and his colleagues have been testing out a bamboo prototype, and they say it performs just as well, if not better. And it improves performance in the materials lab, at the wicket, and even ecologically. Adam Murphy spoke with Ben about the bats...

Ben - So willow's been used for about 200 years for cricket bats, and what you're looking for is a stiff, light material. And we decided to look at bamboo as a more sustainable alternative. So we ran a lot of computer simulations and material testing, and we found that in almost all capacities that bamboo outperformed the willow. So it's both stiffer, more flexible and harder. So this means that when you hit the ball as a player, the ball is going to fly off the bat at a lot higher speed. Which is obviously much more advantageous. And the major benefit is that it's grown close to where the bats are manufactured. Instead of having to ship the willow from England to India, it's grown very close to the facilities to make the bats. So from an environmental point of view, we're cutting down a lot on the carbon emissions from the process.

Adam - And then how do you go about actually turning a stalk into a bat? It's not like you can carve it out from a single bamboo strip.

Ben - Exactly. So the traditional willow bats are all, you cut down a Willow tree and you cut it into the shape straight away, but the bamboo column, or what you see going from the ground is hollow. So what you've got to do is cut it into thin ply. So you split it along the length, and then you glue all these plys together. So you really form a laminate material. And from that, you can cut that to the right shape and then use material processes to finish it into the desired shape of the bamboo bat.

Adam - You mentioned, because it's stiffer it leaves the bat quicker, but what about other kinds of performance? What about for the cricketer picking this thing up? How's it going to go? How's it going to perform?

Ben - The first prototype that we've made is approximately 40% heavier than a traditional willow bat. And this is something we expected because although you see a bamboo column and it's very light, when you process it into its engineered form, it's quite dense. So from a weight perspective, the bat is heavier, but this also means that if you do manage to find the middle of a bat, it travels a lot faster. So when we performed a lot of computer simulations, we found that the sweet spot, or the middle of the bat where you really want to hit it is longer and wider than a willow bat. So this means you've got more room for error when you're timing your shots.

Adam - That all comes into the “sounding too good to be true” end of things. So are there any downsides to how this bat works?

Ben - So, like I said before, I think the major downside is the weight of the bat. and it's something that we're going to look to build some lighter prototypes, which we can then see how that works. But what a lot of people have said is that, you know, they love the traditional sound of leather on Willow. So we tested that, took it to the nets and people said, okay, we can't tell the difference. So we took it into the lab and we said, okay, can we tell the difference here? And it came out that the frequencies, or how it sounds, is very similar, so although we've got a heavier bat, which we're going to look to optimise and make lighter for the purists of the game, who loved that sound of leather on willow, you're not going to lose that. You're just going to have to be getting used to the fact it's leather on bamboo. So the main difference really is the aesthetics and what the bat looks like. But from a materials point of view, and from an ecological point of view, we think we found a more sustainable solution to the problems faced with willow in cricket.

A row of seven white doors arranged in a line

30:00 - What is ADHD?

What is it, and how does it affect those who have it?

What is ADHD?
Henry Shelford, ADHD UK

What’s the scale of the problem and what’s life like for people with ADHD - attention deficit hyperactivity disorder? Henry Shelford is chairman of ADHD UK and he spoke with Adam Murphy...

Henry - It's the worst named mental health condition: attention deficit hyperactivity disorder, and it's woefully negative talking about deficits, disorder. And it's wrong. It's not an attention deficit. It's an issue of controlling the attention. And not everyone has hyperactivity. That's not an essential part. And particularly as people become older in adults, the hyperactive part becomes much less prominent, leaving the majority with, inattentive combined, so there's three kinds of ADHD, hyperactivity, inattentive, and combined, which is a combination of the two.

Adam - It's suggested that like one in 20 people are affected. Does that sound reasonable to you?

Henry - It does, and there's a recent Lancet study that backs that up. So around 5%, so in the UK, that's 3.3 million people, and that's reaching the clinical standard where there's a significant impairment on someone's ability to function. If you take that wider, for people with ADHD traits, it's about 11%, so 7.3 million. And right now, obviously there aren't 3.3 million in the UK diagnosed. So we have a lot of people who have the condition who haven't been diagnosed and are really struggling.

Adam - And what about people like me? You know, the people who struggle and then end up getting diagnosed late. Is that a common story that you tend to hear?

Henry - Well, I was diagnosed in my forties. I know you're going to talk to Dr. Max Davie, and he's in the same position. The majority of the calls to our charity are adults. And one of the things that causes people to realise, is if they might be at a life point where they've got structures and they're doing okay, but something changes and they realise they really aren't. And this period of COVID has changed a huge number of people's way they work. And they've really realised that they have issues. And so we are seeing a lot of adults coming forward, thinking they've got ADHD. The record we know of in the charity of someone who's aged 73, that's the oldest. And we do get a lot of people who, when they realise, that they just say when they learn about it, just everything falls into place. It all makes sense now, how they are. And it shows how important shows like this are in terms of educating people so people can realise and get the help they need.

Adam - What kind of stigmas do you see out there for people making their way through the world with ADHD?

Henry - The biggest one is people not understanding that my actions are traits and not behaviors. So neurotypical familiarity, like the things we've talked about, being late or, bad timekeeping, missing appointments, struggling with deadlines, butting in on conversations, zoning out. It's not, you know, it's not me being rude. It means I've thoughts caught in my head, probably from something you've said, and I'm following it, but that neurotypical familiarity can equal contempt. So people, you know, a lot of people struggle with their to-do list or managing their day, but their struggle is very different from the impairment and absolute destruction of life and careers and jobs and relationships that's happening for someone with ADHD.

Adam - And what kind of fraction of the kids who have ADHD grow up to be adults with ADHD?

Henry - It's thought to be around 60%, take it, carry it on into adulthood. There's some discussion over that number, but I think that the clear point is the majority do. They do tend to, the hyperactive element becomes less prominent, and the less prominence is important because it's actually often better social skills and better controlling of self, that makes it less obvious. You know, you learn to sort of play with your fingers or play with the little thing in your pocket, rather than running around. You're still doing it. But the issues of control of attention, very much remained there. And actually when you're moving out of the structures of school or other education, it then becomes much more difficult. You're supposed to be controlling yourself and obviously you can't and so you can hit real problems there. And certainly as a charity, we get lots of calls in from people, you know, turning 18, going into their first job or into university or leaving university and into their first job, or changes in their workplace. And retirement actually is another big bump where the work structure goes away and suddenly people are struggling to know how to manage their day.

A checklist with all the boxes ticked

35:37 - Diagnosing ADHD

It's a complex condition, so how do you diagnose it?

Diagnosing ADHD
Tony Lloyd, ADHD Foundation

For the people who have it, ADHD, attention deficit hyperactivity disorder, can potentially be a tough thing to deal with. But how do they find out they have it in the first place? What does the diagnostic process look like for ADHD? Chris Smith spoke to Tony Lloyd, Chief Executive of the ADHD Foundation...

Tony - Well in children, what we tend to look at is three core characteristics, which are: inattention (poor memory, inability to maintain concentration, forgetfulness, mind wandering), impulsivity, and sometimes, but not always, hyperactivity. Now these are natural characteristics that appear in all children, aren't they? What constitutes a diagnosis of ADHD is when these characteristics appear in a more extreme form. But increasingly clinicians also look at two other things, which are: low emotional resilience, that inclines towards anxiety and depression; and also what we call 'poor executive functioning skills', which is the ability to manage distractibility and maintain focus in terms of organising your thoughts, emotions, and how you might factor all those things in with how you choose to respond to your environment or not. So with children, we use a whole range of rating scales, but increasingly we're using computer-based cognitive functioning tests such as QB tests, which are over 80% reliable. And they tell us about cognitive functioning, whereas the behavioural rating scales tell us about what the observable presentation is, and that can differ according to context. We know that obviously children with ADHD are going to struggle much more in a school classroom than they are playing out on the playground. So context and environment are really important in terms of how we discern how ADHD is actually impacting on the child.

Chris - And what about when someone presents later in their life? We've been hearing about Adam's experience - would you use the same sorts of criteria? Or do you tend to approach this differently in adults?

Tony - No, we approach with the same rigorous criteria. We use QB testing, and my understanding is that it is going to be implemented by NHS England across the country as part of a national strategy within a couple of years, because it provides that quantitative, objective measure of cognitive functioning. I think what we've got to remember here is that ADHD is significantly underdiagnosed in the UK. The World Health Organisation says that prevalence should be in the region of about 5.26%, but we know in the UK that diagnostic rates are well below 3% and that use of medication is actually below 1%. We are seeing an increasing number of adults coming forward now because ADHD is less stigmatised, people have a better understanding of it, it's not some stereotypical idea about 'naughty children', which is incredibly unhelpful. And people don't understand that ADHD also correlates - undiagnosed or unmanaged ADHD - with anxiety, depression, eating disorders, obsessive compulsive disorder, things like that. So we see people presenting with other mental health conditions, and that's when often we arrive at ADHD as an underlying cause.

Chris - And that could be a giveaway. Yes, indeed. Now given how common this is - I mean, 5% is a lot of people - is it actually becoming more common, or are we just better at picking it up? Where previously we may have ignored it, or not put people in a position where it would have manifested itself the way it is. Or is something else changing?

Tony - One - we're much better at picking it up, and there's less stigma attached to it. And also we're seeing research now that's suggesting that every graduate with ADHD is twice as likely to start their own business; that over 30% of business owners have either ADHD or dyslexia or both. I think we need to understand ADHD in the context of a neurodiverse paradigm: where you have dyslexia, which affects approximately one in ten people; autism, approximately one in fifty; dyspraxia, approximately one in twenty; and ADHD, one in 20; but these things rarely travel alone. 

Chris - You mentioned there's a genetic link there. So does this mean if you see a child manifesting this, one perhaps ought to consider the parents as well? Because they may well also have this, and be like Adam and not realise, and may be able to explain some aspects of their lives on the basis of that.

Tony - Yes, ADHD is over 80% genetic - we're certain. We know that traumatic brain injury, which can be caused by premature birth for example, or traumatic birth, or head injury, can be a cause of ADHD. But for the most part it's genetic, so there's usually some family history. But that doesn't mean to say that either or both parents might have ADHD. We do know that there is an increased prevalence of ADHD with parents who conceive children in their late thirties, or an increased prevalence where parents have had children who've been born preterm; but yes, there's usually a family history of some neurodevelopmental condition, whether it's dyslexia, autism spectrum, ADHD, or dyspraxia.

Brain schematic

43:06 - The ADHD brain

What's going on in the brain of someone with ADHD?

The ADHD brain
Katya Rubia, King's College London

With illnesses like attention deficit hyperactivity disorder - ADHD - some people may say that “it’s all in your head!” That may be the case - but that doesn’t mean it isn’t real. The brain of someone with ADHD is very different to that of someone without it, as Adam Murphy heard from King’s College London’s Katya Rubia…

Katya - ADHD is a neurodevelopmental disorder, which means there is an association with changes in the brain compared to healthy age-matched children. The differences aren't huge - they're on the order of 3%, so these are small differences - but there are differences. So it's not the case that ADHD is just naughty children who suffer from poor parenting, which is often depicted in the media. They have abnormalities in the structure and the function of the brain. The structure is like the hardware, the function is like the software of the brain. And what has been shown over the last three decades of imaging is there are differences in the volume of the brain. They have smaller volumes in areas which develop late in life, like the frontal lobes, the basal ganglia - which is very heavily innervated by dopamine, which is also a transmitter which is deficient in ADHD - which are deep in the brain, and the cerebellum, which is at the very back of the brain at the neck level. These three structures of the brain form networks. And the functions they mediate are late developing functions which you need for mature adult behaviour, like the ability to self control, your emotions, your behaviour, the ability to control your attention, timing functions like looking forward and planning ahead in the future, and the ability to shift your behaviour - so if plan A doesn't work out you have to shift and change. When ADHD children are put in an MRI scanner and they're asked to do an attention task, or a task where they have to inhibit a motor response, or where they have to do some timing tasks, then these areas are not activated in the same way as they are in healthy controls. So they're under-activated and they're smaller in structure. And there's also evidence that these areas are delayed in maturation. What this means is that ADHD children behave like younger children.

Adam - And then how do you actually test that? What do the experiments look like when you put a kid in an MRI - what do you actually ask them to do?

Katya - When you measure the structure of the brain, they do nothing. So they lie in the scanner and we show them usually a video, and they're just asked to lie really still and we just measure the structure of the brain. In functional MRI - that measures, like I said, the software, so the brain functions when they do a task - what we do is we give them a task of attention or a task of inhibition. We give them very short tasks because they get so easily bored. When we started 25 years ago, everyone said, "oh, you cannot scan ADHD children because they move too much in the scanner!" But it is actually possible if you give them very short tasks, and if they're interesting and short and fast, and then you change, you give them a little break, then you do the next task. So that's how it's done. We put them in the scanner for one hour, we give them four tasks of five minutes to do, and then we look at the brain in action, in vivo, while they're doing this task. And that's how we can measure which areas light up when you do this task, and then we compare them with healthy controls.

Adam - You mentioned dopamine there when you were talking. How do those chemicals, those neurotransmitters... what role do they play?

Katya - Neurotransmitters play a huge role in our behaviour and cognitive functions. And dopamine is very important for working memory, for planning, for timing functions. It's also important for self-control. And it's also important for motivation and emotional self control. Noradrenaline is another neurotransmitter that has been shown to be abnormal in ADHD, and this one is very important for tension.

Adam - If the brain in people with ADHD is measurably different, could that be used for diagnosis?

Katya - It could. We have tried to do that. And we have tried to use what's called pattern recognition analysis, where we're trying to find patterns which could classify ADHD children from healthy controls, and we achieved about 80% classification accuracy. But this is still in very early days, because most of the studies we've done so far - I mean, all the studies we've done so far - have been based on group statistics. It's not the case that every child has abnormalities - there are some children who are normal, others are obviously severely abnormal, and then we look at the group. So to diagnose, you need a method which can diagnose individual patients.

a picture of a brain firing off electrical signals

48:03 - How to treat ADHD

What interventions best help people with ADHD

How to treat ADHD
Max Davie, ADHD UK

After making a diagnosis of ADHD, attention deficit hyperactivity disortder, inevitably thoughts turn to managing the condition. But what does treatment look like? Max Davie is a consultant paediatrician and works with ADHD UK, and he took Chris Smith through the treatment options...

Max - Broadly speaking, the two sorts of intervention that I think are most useful are -  one, environmental modification. And then secondly, medication. In children, the first one comes first, the environmental modification. So we would look at how people understand the condition around the child, we'd look at the child's brain health - so essentially that's exercise, sleep and mood. We would support the family at home, and this could be anything from a parenting intervention, to just helping them to sort out their housing - that can be a really crucial element. We need to support them in school, and for an older person into employment or training, make sure everyone understands and that they get the reasonable adjustments that are required within schools to help them through. And then medication at the end, generally, in children, when those things have been sorted out as far as we're able. That's the kind of structure of the interventions anyway.

Chris - What sorts of things in the environment tend to be bad triggers for people that will disclose more ADHD type negative effects?

Max - Yeah. I think you've put that really well actually in that they don't cause ADHD, but they make the ADHD more troublesome. So I mean there's so many of them, but I think a harsh and negative either school or parenting environment will make things worse. Poor sleep is a really big trigger and you can get into a real vicious cycle of sleeping worse, so therefore your behaviour is worse, then your mood is worse. And therefore as any parent will know an irritable and sleep deprived child is often actually harder to get to sleep subsequently. So you can really get into a big problem there. So I think those are two really big ones for me.

Chris - I know you're a paediatrician, but presumably a lot of what you've just said also applies to adults.

Max - Yeah, a hundred percent. I think there is a distinction to an extent in that medications are offered earlier for adults, but the principles are exactly the same. I think that's really important to emphasise.

Chris - Now there's going to be something of a tension because people don't like taking medicines if they can avoid it. And we see this with a whole spectrum of different diseases, whether it's high blood pressure or say depression. People prefer not to have to take medications. But there's an additional element when it comes to children, isn't there, because people are concerned. Medicating children has a whole range of different sorts of manifestations and negative associations, but one of them is people are concerned that because the young brain is still developing, perhaps that could alter its development in unforeseen or perhaps negative ways. Is there any truth to that?

Max - I think the evidence so far is that giving medication to a child who has ADHD, and you've made a proper diagnosis, is probably a benefit to their cognitive development because it gives them more positive experiences. Everything that we do, everything that we put into our bodies or experience, changes our brains. I think that if you give the right medication at the right dose to the right child, it will actually, by giving them vastly more positive experiences going forward, will positively impact their brain development. So I'm not worried about that really.

Chris - And the medications that we use, what are they and how do they work?

Max - Basically they're stimulants, which broadly speaking will stimulate those parts of your brain which supervise the rest of the brain. And they are things like methylphenidate. They are very effective, but they do have some side effects. And then there are non-stimulants, which tend to be a little bit less likely to be effective, but they are a little bit gentler, take a bit longer to work, and they sort of alter the kind of balance of the brain. And they kind of alter the way that these supervisory elements can communicate with the rest of the brain. So two different classes of drugs that work in slightly different ways and can work together quite nicely. So we have a few kind of tricks up our sleeves, even if the first thing we try doesn't work.

Chris - And is that an indefinite thing? People then are almost, I don't want to use the word condemned, but it almost is like that, you have to continue to use these medications indefinitely in order to continue to get that effect?

Max - It's not a life sentence. I suppose my experience is mainly with children and very often what I will say to people, quite often the children are starting this at sort of age seven or eight, and the parents will rightly ask me, is this going to be forever? And I suppose my answer is if it works and they tolerate it, we're probably in for a stretch up until secondary school. And then, frankly, the young person will tell you whether or not they want to carry on with it. And you know they're very clear about that very often. And if they want to carry on with it then they can.

Chris - And do most people elect to carry on?

Max - I mean, well, it's really interesting. My experience in clinical practice is that most people do, but actually, if you look at some of the data on following people up with medication, there is really quite a high dropout rate. But it's just not something that I experienced personally, so I've never quite squared that circle if I'm completely honest.

Chris - And do we have any data on people who do go on medication versus people who don't, is there a sort of a clear direction from beneficial outcomes as to what the best choice is?

Max - So the best data comes from Scandinavian birth registries, as it often does when you're looking at chronic conditions. The comparators that are treatment versus non treatment. So it's not non-pharmacological versus pharmacological treatment. So it's not drug versus non-drug, it's treatment versus non-treatment, but the benefits of treating these conditions over not doing so are absolutely legion. The most striking, the most eye-popping, is that if you treat ADHD, your chances of getting involved in the criminal justice system are halved.

Chris - That's a staggering difference.

Max - It is really staggering. I mean, it's a fairly low number already, but it really is a big big difference. Advantages in employment, education, relationships, all the way through, treating ADHD is better than not treating it. It's not quite the same as saying "the medications do this". And there's a bit of an unanswered question about to what extent medication versus these other environmental modifications or supporting the person's mental health are the crucial elements, but certainly going to seek treatment, getting a diagnosis where it's appropriate, is unequivocally a good thing.

Dog in field

55:31 - QotW: Can dog urine melt a car tyre?

We're looking into this wee-lly important question...

QotW: Can dog urine melt a car tyre?

Urine for a treat, because Phil Sansom's been looking into this 'wee-lly' interesting question from listener Trent…

Phil - Hi Trent. While I don’t doubt your dog’s destructive power, its wee isn’t going to eat through that tyre - not in a lifetime of walkies.

To understand why, let’s look at what happens when the rubber meets… the flow. Starting with the flow - that is, urine.

Urine in mammals is about 95% water. The remaining 5% is various waste products of metabolism, like urea, mineral salts… and indeed, uric acid. That can mean that urine is slightly acidic.

But uric acid isn’t particularly strong. And compared to in birds, where all that white stuff in the droppings is uric acid, in mammals there isn’t that much of it.

The result is that dog urine normally ranges from only mildly acidic to even mildly alkaline. And the actual acidity will vary depending on the dog’s age, diet, and health.

What about the tyre then? Modern pneumatic tyres are usually made of cords of steel or fibre, covered in rubber. 

In fact, our tyres have been made out of rubber ever since Robert William Thomson invented them in 1846 - forty years before even the first car.

The reason being, rubber is firm enough to resist the road, but flexible enough to be comfortable on uneven ground - plus, the rubber is vulcanised, meaning that cross-links between the long molecular chains make it even harder.

All this is to say that rubber is a very resilient material, not known for its vulnerability to chemicals.

Unfortunately I don’t know if anyone’s done the specific experiment that would precisely answer your question. You should be the first! But - the rubber seal manufacturers Mykin do supply a chemical resistance chart to make sure you’re using the right type of rubber for your environment. SBR (the most common type of tyre rubber) has the highest possible rating against uric acid, meaning that they’re expecting it to be barely affected.

That’s why I’m confident in saying you’re not going to be done in for vandalism. I also asked David Williams, a vet from the Queen’s Veterinary School Hospital, who agreed that the wee would have no effect on car tyres! He says the more interesting question is how your dog is using it to communicate with other dogs, through what he calls ‘pee-mail’.

Thanks for your question Trent. Next time, listener Kelvin has a dieting trick he’s thinking of trying out...

Kelvin - We are told not to overcook our vegetables because this kills the nutrients. Now if that's the case, why don't we just overcook the food we enjoy and not run the risk of putting on weight?


Thank you for this show. It was a great session (well mostly) but I remember feeling sick to my stomach after hearing Katya Rubia's call ADHD folk "severely abnormal" and contrasting them with "healthy controls". ADHD isn't a disease and marginalising people adds to mental health issues and suicide levels. For folks with rejection sensitivity dysphoria, telling them that they are diseased and broken is just punching down.

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