Many people are still living with ADHD without a diagnosis or support but an NHS-funded review suggests the real numbers with the condition is not on the rise
Diagnosing children with ADHD is based on “arbitrary thresholds” which could cause the NHS to wrongly prescribe children drugs for the condition, experts warn.
Around three million Brits are thought to have Attention-Deficit/Hyperactivity Disorder and despite heightened awareness of the condition many remain undiagnosed. But an NHS-funded review has found “evolving diagnosis criteria” may be in part why more people are being diagnosed but could find no evidence of a real increase in people with the condition since 2020. Leading experts insist the NHS is still playing “catch up” after generations when there was no recognition of ADHD and many girls in particular remain undiagnosed.
Study author Dr Alex Martin, of King’s College London, said: “While assessments and help-seeking may be increasing, our study has shown significant gaps in the tracking of ADHD prevalence, resulting in a frustratingly unclear picture. The best data we have suggests that there has been no meaningful increase in ADHD prevalence.”
ADHD is characterised by difficulty focusing on things, hyperactivity and impulsivity. A previous study on seven million Brits showed there had been a 20-fold increase in people receiving a diagnosis for ADHD between 2000 and 2018. Among men aged 18 to 29 there was a 50-fold increase.
But experts warn clinicians may feel pressured to make “artificial decisions” as changing cultural norms drive increased demand for children struggling at school to be diagnosed and get support. They warn about the risk of children wrongly being given ADHD drugs and say clinicians should be able to “undiagnose” them if they improve.
Prof Phillip Shaw, director at the Institute of Psychiatry, Psychology and Neuroscience at King’s College London, said: “Giving medications for ADHD to people who don’t have it – that’s never a good idea. They are generally very safe medications… but they do have side effects and they have to be monitored.”
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The NHS is pulling together better national data on ADHD which can significantly interfere with daily life and development. The neurodevelopmental condition can affect things like schoolwork, daily tasks and social interactions. The new paper by King’s College London is the first systematic review of ADHD prevalence to be published since the start of the Covid-19 pandemic and looked at 40 studies.
Prof Edmund Sonuga-Barke, of King’s College London, said: “The history of ADHD in the UK is one of chronic under recognition so the increase in diagnoses we’ve seen over the last ten or so years is really a resetting or a catch up. And there’s actually plenty more to do in this regard.”
However Prof Sonuga-Barke said diagnosis uses “essentially arbitrary ADHD thresholds” that are “not based on any natural, biological or clinical boundary”. He added: “This forces us to consider how those thresholds are socially determined and culturally dependent. The fluidity around boundaries between ADHD and not ADHD inevitably leave clinicians having to make rather artificial decisions about very fine margins.”
Prof Phillip Shaw, who is one of the country’s leading experts but was not involved in the research, said: “For kids who are in the grey area there are three options here; to make a diagnosis or not, or often we just wait and watch. And for those kids in particular we always start educating the family and the child about what ADHD is and seeing if there are strategies they can use at home to help them. We also place an enormous emphasis on accommodations at school for the hyperactive kid [such as]… let them do their work standing up, maybe have preferential seating for inattentive kids, do things to break it [the work] up. You’ll find all really good teachers already do this.”
People with the neuro-developmental disorder may have trouble concentrating or sitting still, while other symptoms include being easily distracted, forgetfulness, finding it hard to follow instructions or organise time, and making impulsive decisions. Best estimates from a 2018 study suggests true prevalence of ADHD among children could be 5%. Back then 2.5% of boys and 0.7% of girls in the UK had been diagnosed but this is likely to have increased since then. An estimated 2-3% of adults had ADHD but only around 1% had a diagnosis.
Prof Phillip Shaw warned children with other mental health problems such as anxiety could be mistakenly labelled as having ADHD. He added: “My hunch is that there’s such a huge awareness of ADHD that it’s often used as a language of distress. It’s sometimes used to express that children and young people are struggling, particularly at school, and need help. And of course, when a child is having problems that are impacting their life in a sustained way, they deserve a full mental health assessment, even if the final diagnosis doesn’t end up being ADHD.”
Researchers admitted all but four of the studies included in the review were “poor quality” and more research is needed. However surveys included did suggest there has been “no significant rise” in the number of people who actually have the condition since 2020. Social media platforms like TikTok have played a role in raising awareness.
Earlier this month NHS England estimated for the first time that 2,498,000 people in England may have ADHD, which includes those without a diagnosis. An estimated 741,000 are children and young people aged five to 24. More than half a million people (549,000) were waiting for an ADHD assessment at the end of March 2025, up from 416,000 a year earlier.
Catherine Hinwood, NHS England’s ADHD Programme Director said: “This research backs the long-term vision set out in our recently published ADHD data improvement plan to have accurate national data on all aspects of ADHD – and we published our first ever national ADHD data set including estimated prevalence figures last week. Patients are waiting too long for an ADHD assessment and diagnosis and that’s why the NHS has also launched an independent taskforce to investigate the challenges facing services and help them manage the rising numbers of referrals, with support from across society.”
This study was funded by NHS England and was conducted by the NIHR Health Protection Research Unit in Emergency Preparedness and Response. It is published in the Journal of Affective Disorders.