Unless you've been paying ironically little attention in recent years, you'll have noticed the significant rise in adults being diagnosed with attention-deficit/hyperactivity disorder, more commonly known as ADHD.
While some people blame this on schools and education, others predictably point their fingers at phones and screens. The more cynical types insist it’s not actually happening at all – saying it’s just a fad, or a bandwagon, or another term meaning “people are making it up to get attention or excuse their laziness.”
Despite the unwarranted prominence of such views, the evidence tells a different story.
Some studies suggest there’s been a 20-fold increase in ADHD diagnoses in the UK since the year 2000. Others describe a seven-fold increase in adult ADHD diagnoses over the last 10 years. There’s also the 20-per-cent increase in the amount of ADHD medications prescribed between 2021 and 2022 alone.
Presumably related to this, the same time period saw, for the first time, more adults being prescribed ADHD medication than children.
Whatever figures you use, it’s hard to ignore that ADHD diagnoses are on the rise.
Indeed, the latest evidence indicates roughly three to five per cent of the global population has ADHD. Even at the most conservative estimate, that would mean over 240 million people have ADHD, with over 2 million in the UK alone.
Again, that’s only a conservative estimate; some studies suggest that 1 in 10 young people in the USA have ADHD. In spite of all this, ADHD in adults is still widely underdiagnosed. And the idea that it’s some attention-seeking fad continues to pervade the mainstream discourse, largely unchecked, to the extent that there’s now a book about ADHD literally titled It’s Not a Bloody Trend, by Kat Brown.
Why? Probably because the general understanding of ADHD, particularly in adults, leaves much to be desired. So, here’s the reality of life with ADHD, according to both the science and some of the people who’ve experienced a later-in-life ADHD diagnosis.
What 'causes' ADHD?
At the most fundamental level, most people a re probably getting the underlying cause of ADHD wrong,
because nobody actually knows for sure what it is. Not yet anyway.
As with most brain-based issues, there’s not one simple culprit to single out. Research suggests that the root causes of ADHD are legion and often intertwined. Much research has observed that in children and adolescents with ADHD, the cortex (the uppermost layers of the brain, where important cognitive processes occur) is thinner than average, implying fewer neurological resources available to handle complex cognitive tasks.
Other studies suggest this thinning is particularly prominent in brain regions like the prefrontal and parietal cortex, areas of the brain heavily involved in processes that include self-control, forward planning, movement and emotional reactions. All things that are regularly affected by ADHD.
Development of white matter (made up of neuronal tracts that link brain regions together, allowing them to communicate), is also affected in ADHD, with some studies suggesting it leads to more white matter, not less.
This may sound like a positive, but excessive white matter may cause neurological ‘white noise’, impairing
the cognitive processes that underpin focus, concentration and control. Also, the development of sophisticated cognitive abilities, such as focus and intelligence, involves removing unnecessary connections to increase neurological efficiency.
Disruption of this process is believed to be a factor in ADHD, autism and other types of neurodiversity.
Another aspect of ADHD may be an impaired ability to switch between the default and task states. The default state is when your brain has nothing particularly to do, so your mind wanders and you ponder things.
The task state is when you have a task to work on, so are focused and concentrating.
If you struggle to stop your mind from wandering when you’re meant to concentrate and focus, that would logically make completing tasks, and many other things, trickier. What causes all these changes in the brain, though?
Well, ADHD is very heritable. Heritability means the likelihood that a certain trait someone has is due to their genetics (ergo, you inherit it from your parents). Evidence suggests ADHD heritability is as high as 80 per cent, putting it on a par with more familiar heritable traits, such as height or intelligence.
While certain external environmental factors are also linked to ADHD – foetal alcohol damage or birth difficulties, for example – they’re primarily things that happen in utero. Evidence suggests genetics are the main cause of ADHD; it’s mostly nature, rather than nurture.
This doesn’t automatically mean there’s one specific ADHD gene, however. At present, there are 76 different genes that contribute to the development of ADHD. Which is… a lot.
Unfortunately, all these myriad factors contributing to ADHD mean it can be a very difficult condition to pin down. It can manifest in a wide variety of ways. As a result, there are many different diagnostic criteria and ADHD can take a wide range of forms.
You know how autism exists on a spectrum? The same applies to ADHD.
So, even if we can’t say for certain what the root cause is, the idea that there’s only one type of ADHD that everyone with it should conform to, and that everyone else will easily recognise, can be safely ruled out.
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Is ADHD a children's problem?
Most people think of ADHD as something that affects children specifically. But is this accurate? In some ways, you could argue it is. ADHD is classed as a developmental disorder, meaning it’s more apparent when an individual is developing – during childhood, in other words.
Because of this, our understanding and approach to ADHD has been heavily influenced by childhood manifestation. Indeed, the ‘H’ in ADHD stands for hyperactivity, the outward expression of which lessens or disappears in adults with ADHD.
Basically, ADHD is often more ‘visible’ in children, via overt behaviours. It also often co-occurs alongside other neurodevelopmental conditions, such as dyslexia, dyspraxia and epilepsy.
ADHD in adults typically looks very different. Hyperactivity has receded, but inattentiveness (difficulty with concentration and focus) remains unchanged. While still a big problem, it’s much less visible, externally.
Hyperactivity often disrupts the environment around you (and the people within it); inattentiveness, less so. And if it does occur, in most circumstances its consequences aren’t as disruptive, although inattentiveness while driving can be very consequential.
ADHD in adults also often has many co-occurring problems. But, rather than neurodevelopmental issues, they tend to be mental health disorders, like depression, anxiety and substance abuse.
Such things are more common, and more readily identifiable, than a diagnosis of ADHD in adulthood. These more familiar conditions can effectively obscure ADHD, leading to regular misdiagnosis, in a similar way to how so many women with endometriosis have it diagnosed as irritable bowel syndrome or polycystic ovaries.
Hence, many adults with a history of mental health issues are ‘suddenly’ being diagnosed with ADHD (although it’s rarely sudden from their perspective).
Why such stark differences between ADHD in child- and adulthood? To the extent that some argue they should be treated as different conditions?
Well, ADHD may be a developmental disorder, but that doesn’t mean brain development doesn’t happen. It does. The usual maturing processes that result in older individuals having greater coordination, self-control and emotional regulation all still occur, which logically means the more child-centric aspects of ADHD eventually subside.
But if typical brain development is like a cross-country run (a long and arduous, but ultimately healthy process), having ADHD and developing into a functional adult is like a cross- country run while wearing a backpack full of rocks. It’s doable, but you won’t be as fast, and you’ll be more exhausted and drained by the process.
Many adults with ADHD know this all too well, and are keenly aware of how much easier their lives could have been if only they’d been diagnosed at an earlier age and received the appropriate treatment and accommodations, or even just acknowledgement of their disorder.
This is the view of Dan Mitchell, a writer, museum worker and PhD researcher in mythology and folklore, who was diagnosed with ADHD as an adult. He says that all the misdiagnoses and problems he endured in his younger years almost hurt more now, with the knowledge that they could have been avoidable with the right help.
“The feeling of ‘if only I knew then’ is so much more heightened than with regular screw-ups. [I keep thinking back to all the] relationships and education opportunities I missed out on.”
And it makes sense that those with undiagnosed, untreated ADHD would have more difficult lives. When you consider how frugal the brain can be with resources, how demanding focus and concentration are, and how big a role stress plays in mental health problems, the very act of living with ADHD and fitting into the neurotypical world is a huge mental drain.
The fact that we’re only now figuring this out doesn’t diminish the impact it’s already had on countless people.
Can women have ADHD?
While it’s children who are more commonly associated with ADHD, we could be even more specific and say ADHD is typically associated with badly behaved, chaotic young boys.
The ratio of males to females with ADHD is anywhere from 2:1 to 5:1. But in clinical populations of children receiving treatment for ADHD, boys outnumber girls almost 10:1. The most obvious explanation for this is the fact that ADHD in childhood is identified via disruptive, hyperactive behaviours.
And it’s invariably boys who exhibit these traits. ADHD in young girls tends to manifest more as inattentiveness, a reduced ability to focus and/or think things through. While this usually (but by no means always) leads to poor academic performance, damaged self-esteem and other issues, it’s far less disruptive to the environment around them.
As ADHD and Autism researcher Eluned Parrott points out, much ADHD assessment happens via schools, and schools logically put forward children who are the most disruptive.
“The students who mostly struggle or are anxious (meaning, girls) are regarded as ‘normal.’ As they say, it’s not a problem until somebody throws a chair.”
Also, ADHD in children heavily informs the clinical understanding and approach. And if boys make up most ADHD cases, the approaches will, inevitably, skew towards male characteristics. As a result, girls and women with ADHD are regularly un- or misdiagnosed and have to endure the consequences of life with an untreated condition, such as reduced wellbeing, poorer career and relationship prospects, and more.
“Self-concern, self-worth, such things impact on your whole life, and are seriously harmed by ADHD. Especially in women.” Parrott says. It’s not that women with ADHD can’t succeed. It’s just going to be harder for them than it already is.
As our understanding of ADHD improves, ADHD in women is becoming easier to identify. Hopefully, the notion of ADHD as ‘not for girls’ is well and truly on the way out.
Is ADHD a 'new' thing?
Claims that adult ADHD is just a ‘fad’ suggest it’s a thoroughly modern invention. Obviously, it isn’t. Although the term ADHD only appeared relatively recently, the first official record of symptoms we would now likely deem to be ADHD dates back to 1798.
There’s no reason to suspect it hasn’t been around for considerably longer, though. Conditions involving
multiple brain regions and dozens of genes don’t pop into existence overnight. But if that’s true, why does it suddenly seem more common? And where has all this ADHD in adults been before now?
Well, there’s the ever-increasing awareness and understanding of ADHD, in both clinical experts and the general public, enhancing the ability to identify and report symptoms and seek help. Especially the interconnectedness produced by smartphones and social media.
Also, changes in the ADHD diagnostic criteria have made it easier to diagnose.
As for where ADHD in adults has been ‘hiding’? We’ve seen that ADHD can be obscured by, or mistaken for, anxiety and depression, which are the two most common mental ailments on Earth. How many of those millions of diagnoses actually have ADHD lurking beneath the surface?
And while you should never ‘armchair diagnose’, famous figures from the past are often said to have had ADHD, for example, Kurt Cobain, James Dean and Clark Gable. There was also that famous Italian inventor
who could never stay focused on one specific thing for very long.
Just because we know and recognise ADHD better in the modern day, doesn’t mean that it hasn’t been there all along. Germs, for example, were only discovered in the 17th century, but they’ve been making people sick for much longer.
Can ADHD be an advantage?
While it’s not the most prevalent view, there are some people who contend that ADHD shouldn’t be considered a disorder in the first place. There are those who even describe it as a superpower.
While that may be hyperbolic, some studies suggest that ADHD can be beneficial.
Experiments reveal that those who display signs of ADHD are better at foraging (presumably because a tendency to keep thinking ‘what else is around?’ is useful) suggesting that ADHD is an evolved trait. Which would explain why it involves so many genes and brain regions.
A more modern perspective suggests that ADHD may enhance your ability to navigate and interact with the digital world, which is typically made up of multiple information sources clamouring for attention simultaneously.
But even if we accept these arguments, they’re just two specific contexts (one of which is prehistoric) in which ADHD can be useful. As the abundance of data and most people who deal with it will attest, much of the time, the condition is a problem.
Should you feel bad about taking medication for ADHD?
Thankfully, in the modern world, ADHD is another condition that can be, if not cured, then managed and lessened with medical interventions, such as drugs and therapy. These days, however, taking medication for any sort of mental or neurological condition is still stigmatised by some and seen as a source of guilt and shame.
The sociocultural reasons for this are many and varied, but suffice it to say, it happens with ADHD with bleak regularity. The default ADHD medications, namely Adderall (dextroamphetamine) and Ritalin (methylphenidate), are stimulants and there are many who think stimulants are bad.
As a result, many people, including medical professionals, assume those seeking help for ADHD are faking it, to get a ‘fix’. Once again, evidence reveals a very different reality.
Such medications have repeatedly been shown as safe and effective in tackling the symptoms of ADHD. Indeed, they have one of the highest response rates in all of medicine. And while there are many reports of students, in particular, abusing ADHD medication to help ‘focus’ and pass exams, this doesn’t work. Not for neurotypical people, anyway.
The medication works by replacing chemical activity in the brain that’s reduced by ADHD. But a typical brain has nothing to replace. So ADHD meds often make things worse; it’s similar to the way that someone with a severe injury often benefits from opiate painkillers, but taking them when you’re fit, healthy and uninjured is unhelpful.
This isn’t to say that ADHD medication is some sort of magic bullet or cure-all. As Nick Pettigrew, a best-selling author who also has ADHD, puts it, “[When it comes to] ADHD medication, it’s as if my whole life I’ve had a broken leg that will never heal. I’d somehow managed to make it into my 40s, dragging myself around on it. My diagnosis and tablets is like being given crutches for the first time. I still have a broken leg, that’s not going away, but moving through the world is now a bit easier.”
Sadly, the very existence of brain- based ailments seems to upset certain people, as does anything that reinforces it. So medication is seen as bad, private diagnosis is bad, blaming it for your issues is bad and so on.
Such stigma and judgement can only make things worse for people with ADHD.
As Angela Barnes, a comic and former social worker, puts it, “[I often get] sarcasm, backlash and eye-rolling when I mention ADHD. The idea that I’m trying to be fashionable… I wish those people could see what I’ve been through over the last 30 years!”
Basically, there are people who will insist that ADHD is not a ‘disorder’ at all. Some may not mean this cynically, and genuinely believe that those who have to deal with it just need to have their environments adapted to complement how they think and function. Which is certainly a noble, inclusive stance and a valid goal to strive for.
But we don’t currently live in a world where that’s possible. We do, however, live in a world where the causes, occurrence, effects, expression and requirements of ADHD are still widely misunderstood, if they’re even acknowledged at all.
This needs to change. And change properly, with significant societal adaptations and adjustment. Because
even if you ignore the fact that it’s just the morally right thing to do, the economic cost of undiagnosed and untreated ADHD adds up to billions. No amount of opinion pieces insisting it’s a ‘fad’ can ever hope to compensate for that.
About our experts
Dan Mitchell is a writer, museum worker and PhD researcher in mythology and folklore. His work has been published in The Ghastling magazine, The Guardian, and he has appeared on BBC Radio 4.
Eluned Parrott is an ADHD and Autism researcher based in Wales. She ran a research project for Wrexham University investigating the wellbeing of women with autism or ADHD.
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