The rise of the ADHD diagnosis – an explainer!

Picture of Paul Ginsberg

Paul Ginsberg

Graph entitled "History of left handedness", showing an increase in left-handedness diagnosis between 1920 and 1960, following by the curve rapidly levelling off

This was all preped and ready to go next week, but it seems timely today with the release of the independent review into mental health conditions, ADHD and autism by the UK Government.

Which the BBC headline claimed “ADHD and autism at risk of over-diagnosis, says report, as author warns of rise in mental ill health”

and yet the report stated “On the basis of evidence available to us we CANNOT conclude that overdiagnosis is occurring at scale”. In fact the report’s author explicity says that Wes Streeting, the former health secretary who commissioned the report was WRONG.

What’s happening now is that there’s a trend, where more people are diagnosed. When the natural level is reached, that upwards trend will stop because… science. But don’t let the facts get in the way of a good headline. For more pausing, reflecting and opportunities to think through what’s really happening, feel free to book a coaching taster session with me. On offer all this month! Or read the article below, to see the comparison with that trendy scourge of being left-handed.

For more pausing, reflecting and opportunities to think through what’s really happening, feel free to book a coaching taster session with me. On offer all this month!

A modified version of this article originally appeared on the Scottish ADHD Coalition website (author: yours truly), and had a good response, so I thought I would bring it to my newsletter. There’s also a whole support section there, including articles on assessment, medication, and extra options you might want to consider as food for thought.

I’ll cover

  • The background
  • What’s behind the increase?
  • Changes in society
  • A comparison with left-handedness
  • Growing assessment backlog
  • The responsibility game
  • Future opportunities
  • Disclaimer

Background

Requests for ADHD assessments in some areas of Scotland have skyrocketed by 2000% in 5 years between 2020 to 2025 with at least 42,000 and 23,000 adults currently waiting for an assessment (most recent figures, from October 2025), with waiting lists only heading in the wrong direction. Scotland isn’t alone in this, with demand increasing in many countries.

This has put existing services under severe strain. Traditional NHS psychiatry clinics, never well-funded at the best of times, have not been able to scale to cope.

There is literally no evidence to suggest that those seeking a diagnosis are doing so incorrectly, or at least anything more than for any other medical condition. Based on conversations with private clinics, 90% of those seeking a diagnosis – on average – will get a result confirming they have ADHD. This figure has not changed in years. This is not to seek to dismiss the remaining 10% who may have complex needs – it’s “just” that an ADHD lens is not appropriate, and they could be better off supported by a different treatment pathway. It is also why a formal diagnosis stage exists – to separate out the difference between ADHD symptoms and different underlying causes.

Overall there is huge underdiagnosis. As of January 2025, just 0.32% (1 in 300) of the British population have a formal diagnosis on their medical record, whereas it states the likely rate will be around 2.8% (the Scottish ADHD Coalition’s own estimate is higher).

What’s behind the increase?

The underlying increase seems to be a result of a few interconnected immediate factors:

  • Better understanding of ADHD
  • Improved communication from the ADHD community
  • Reduced social stigma
  • Changes in society, technology and work

In 2013, DSM5 was published and includes a better criteria for diagnosing ADHD. DSM5 stands for the “Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition” and is the primary reference book used by mental health and medical professionals to diagnose mental illnesses. It is published by the American Psychiatric Association (APA), but heavily referred to by UK professionals too.

No longer is it a case of “You can have ADHD or autism, but not both. Which one would you like?” Instead there is broad recognition that autism and ADHD co-occur. In fact, around 40% of ADHDers have autism.

With the update to DSM5, doctors take around 5 years to go through medical training. You can then see the significant uptick in social media references from 2018 onwards. Take in the covid lockdowns, where people had time to sit and reflect, and the sudden increase in diagnoses becomes more explicable.

It’s not that there wasn’t ADHD before, it’s just that it wasn’t identified.

Discrimination

In the 1950s ADHD research was conducted by white middle class men on white middle class boys. This is called “sampling bias” – it turns out that if you don’t check on certain populations, they will not be counted nor considered.

The discrimination and effects of discrimination are still with us today. Although improving, this affects both research and assessments. The bias in research subjects particularly affects black people. For instance there have been relatively few studies on black ADHD women; they are more likely to be misdiagnosed as having schizophrenia. Assessments are less accessible for girls and women too – young girls will typically have more healthcare visits before being assessed for ADHD than boys, and women are still more likely to be misdiagnosed as having bipolar disorder.

Changes in society

Prior to the modern understanding of ADHD, people would (and still) self-medicate to deal with the more unwanted symptoms, whether that’s drugs or alcohol to calm the brain, or gambling and other risky behaviour to feed a need for dopamine. These behaviours are sometimes called “maladaptive”, because they may cause harm.

People now drink less, so ADHD-related issues which would have otherwise been masked, are easier to identify. Overall this is a good thing, but it shifts recognition and creates demand as people realise that there are options and opportunities, to help them with their challenges.

These days, there are a number of interventions, from prescription medication to adjusted CBT (and it’s newer cousin, Dialectic Behavioural Therapy) and coaching, to address these issues.

The changes in society aren’t all positive however. With the relative abundance of sedentary jobs (rather than outside working), this means that key opportunities for self-regulation such as exercise are reduced. Also the concept of “normal” is relatively modern.

As with the above article, we would question whether the modern education system, with its focus on example and reduction of creative opportunities, exacerbates – or even creates – the problem. Equally, whilst the internet brings many benefits, US courts have agreed that smartphones cause substantial harm and we suspect that our population may be at particular risk. To be clear, it is not that we think we can do without smartphones, but there is nuance to be had in how we engage with new technologies.

A comparison with left-handedness

Graph entitled "History of left handedness", showing an increase in left-handedness diagnosis between 1920 and 1960, following by the curve rapidly levelling off

For those still surprised at the rapid rise in ADHD assessment demand, a comparison can be made with being left-handed.

For centuries, being left-handed was regarded as a sign of bad luck, or having evil spirits. Corrective measures included forcing people to write with their right hand, which then caused issues such as speech impediments, due to neurological interference in using a non dominant hand.

In 1900 the rate of left-handedness was around 3%, and from there until 1960 it rose until the rate hit 12%. From there it suddenly plateaus. The reason for this is that knowledge improved and that reduced stigma. People were gradually free to use whichever hand suited them best. We feel the same is happening within the ADHD and broader neurodivergent community, albeit on a much more expedited timescale!

Growing assessment backlog

Back in 2012, a year for which we have reliable figures, NHS Scotland had 5000 children receiving support for ADHD. Based on a 5% rate this should have been nearer 37000. By 2025 the waiting list for assessment alone (not those already assessed and in support) was 9,680 in Lanarkshire. This is further supported by work that the Royal College of Psychiatrists undertook in 2024, which showed significant regional variations in Scotland.

Services, if they had ever coped, have largely given up the ghost. More people are joining the waiting list than are being seen by appropriate specialists in the same time frame. Some services have closed their doors to new assessments, a stance which is now being challenged in the courts.

The responsibility game

The Royal College of Psychiatrists in Scotland recently warned: with no dedicated services in place, people with ADHD and autism are being pushed into general mental health services – not because they have a psychiatric illness, but because there is nowhere else for them to go.”

Whilst this ignores the fact that untreated mental health issues regularly lead to psychiatric illness, it illustrates a wider point. Each service in Scotland thinks that ADHDers should be someone else’s responsibility. Again, someother countries are more advanced!

The issue is that ADHD is complex and cross-disciplinary, needing specialists in subjects such as:

  • Psychiatry (particularly when it comes to prescribing stimulant medication)
  • Clinical psychology
  • Speech & language therapy
  • Occupational therapy
  • Counselling
  • Coaching

It requires a team approach, and that’s not something NHS Scotland is currently set up to deal with.

Psychiatrists don’t think that ADHD is a psychiatric illness, which is what they are set up to deal with, however neurodevelopmental health still comes under the responsibility of Community Mental Health Teams. 

The Royal College of Psychiatrists in Scotland said in a recent submission to the Scottish Parliament “The reality on the ground is that our healthcare model is designed to meet the needs of 1 per cent of the population, but it is trying to meet the needs of more than 20 percent of the population. That cannot and will not work.” This is the case for many other healthcare systems elsewhere too.

At the time the report was submitted, Member of Scottish Parliament for Mental Wellbeing, Tom Arthur, said “The mental health system in Scotland cannot cope with it, but no mental health system in the world can meet that level of demand.” We profoundly disagree with this, based on examples from the Netherlands, Canada and beyond. 

Our takeaway is that there are systemic challenges and the existing system isn’t designed for, or coping with, a situation where 5% of the population (our view on the ADHD rate) need assessment and assistance. It will take attitudinal and practical change to address this which is a topic for another article!

Found this post interesting? Click “like” on LinkedIn, as this really helps me and supports my work, or feel free to share. I write about neurodivergency matters, with a dash of inclusivity and tech. Subscribe directly to avoid missing out; you can also have a nose through my back catalogue. Want even more? You can follow me on Bluesky and/or LinkedIn.

Observations, thoughts or additions to share? Feel free to comment!

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