Experts are warning that far from being over diagnosed, people with ADHD are waiting too long for assessment, support and treatment.
In a paper, published today in the British Journal of Psychiatry , a group of experts led by Professor Samuele Cortese from the University of Southampton say there is no robust evidence that ADHD is over-diagnosed in the UK.
The new paper refutes the view that ‘nowadays everyone has ADHD’ which is gaining traction in public discourse and has been amplified by some leading politicians, as demand rises for NHS assessments and services.
Bringing together academics, clinicians, people with lived experience and carers, the group say this narrative risks misleading the public and policymakers and overshadows a more pressing concern - unmet need.
Professor Cortese said: “Rather than focusing on increases or decreases in diagnostic rates, attention should be directed toward the extent to which those with ADHD are being adequately diagnosed and treated.
“While misdiagnosis and inappropriate diagnosis do occur, the available evidence indicates that under diagnosis and under treatment remain the predominant challenges.”
When standardised diagnostic criteria are applied, the prevalence of ADHD internationally is around 5 per cent in children and 3 per cent in adults.
While prevalence has increased over time, NHS administrative data in England remains substantially below these expected levels, suggesting that many people with ADHD are living without a diagnosis and adequate support.
The group acknowledge that misdiagnosis can occur in some cases, particularly where assessments rely heavily on self-reporting or where alternative conditions are not fully considered.
Professor Tamsin Ford, Head of the Department of Psychiatry at the University of Cambridge, a coauthor on the paper, commented: “While many more people with ADHD are being recognised and treated, we are failing to support many more. Overdiagnosis is not a problem, but misdiagnosis may be as people are driven into the private sector by long waits; and sadly, missed diagnoses remain common.”
The researchers stress that the absence of biological diagnostic markers means that thorough, multidisciplinary clinical assessment is essential. Field trials show that when clinicians are properly trained, an ADHD diagnosis is among the most reliable for a mental health condition.
“Similar to physiological traits, such as blood pressure or weight, ADHD symptoms are distributed along a continuum,” says coauthor Professor Chris Hollis from the University of Nottingham. “But as with hypertension or obesity, there are diagnostic severity thresholds that determine health risks and what interventions should be used. Similarly, in ADHD a risk-stratified stepped-care approach may be useful.”
Professor Cortese and colleagues highlight significant pressure on UK services, with long waiting times and growing demand, especially among adults who were not diagnosed in childhood.
They point to figures showing that around 27 per cent of children and young people diagnosed with ADHD reported waiting one to two years, while 14 per cent waited two to three years.
Evidence shows that untreated ADHD is associated with serious long-term risks, while effective treatments are available, backed by strong evidence, and generally well tolerated.
“The costs of untreated ADHD are often overlooked,” says Professor Cortese. “They include increased risk of academic failure, suicidal behaviour, substance abuse, criminality, injury and death. The failure to provide treatments which have been shown to reduce these risks represents a major ethical issue that needs to be urgently addressed.”
The authors call for improved funding, workforce training and a more balanced, evidence-based conversation to ensure accurate diagnosis while expanding access to care for those who need it.
The researchers are supported by the National Institute for Health and Care Research (NIHR), UK Research and Innovation (UKRI) and the Office for Life Sciences.
ADHD (over) diagnosis: fiction, fashion, and failure is published in the British Journal of Psychiatry and is available online.
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The British Journal of Psychiatry
ADHD (over) diagnosis: fiction, fashion and failure
6-Mar-2026
C.A., S.C., J.D., D.F., T.F., B.D., J.G., I.H., M.H., C.H., M.K., H.L., P. Majumder, P. McArdle, D.N., D.O., G.S.-d.-P., P. Santosh, K.S., S.S., P. Shaw, E.S. and P.W. are members of the UK Child Psychiatry Research Society (CPRS). S.C. has declared reimbursement for travel and accommodation expenses from the Association for Child and Adolescent Central Health (ACAMH) in relation to lectures delivered for ACAMH, the Canadian ADHD Resource Alliance, the British Association of Psychopharmacology, the Healthcare Convention and the CCM Group team for educational activity on ADHD, and has received honoraria from Medice. S.C. is the Chair of the European ADHD Guidelines Group (EAGG) and a member of the Steering Committee of the European Network for Hyperkinetic Disorders (Eunethydis). P.A. has in the last 5 years received payments for consultancy and/or educational talks from Takeda, Jannsen, Flynn Pharma, Medice and AGB Pharma, and royalties from Professional Association of Teachers of Students with Specific Learning Difficulties and Cambridge University. C.H. receives grant funding from UKRI and the NIHR. He was a member of the NICE ADHD Guideline committee (NG87) and NHS England ADHD Taskforce Experts in Evidence group. C.H. is a member of Eunethydis and EAGG. T.F. receives grant funding from UKRI and NIHR, and her research group receives funding for research methods consultancy with Place2Be, a third sector organisation providing mental health training and interventions in UK schools. T.F. is an editorial adviser to the BJPsych editorial board but did not take part in the review or decision-making process of this paper. D.F. sees patients with ADHD in private practice and is contributing to a revision of the Royal College of Psychiatrists’ training advice for ADHD and sits on a NICE Technology Appraisal Committee. M.K. is Editor in Chief, BJPsych International; Portfolio Editor BJPsych. He did not take part in the review or decision-making process of this paper. H.L. works for NHS England. D.N. is supported by the NIHR Applied Research Collaboration Northwest London and NIHR Imperial Biomedical Research Collaboration. P. Majumder is a member of the CPRS. G.S.-d.-P. has received honoraria from Janssen Cilag, Lundbeck, Angelini and Menarini. A.P. receives grant funding from UKRI and NIHR and is a senior member of Eunethydis. T.N-D. is a senior member of Eunethydis. E.S. has received an honorarium from Medice. C.A. has received honoraria for independent academic presentations at training events organised by Takeda and Flynn Pharma. P. Santosh has declared reimbursement for travel and accommodation expenses from the British Association of Psychopharmacology, and the Egyptian Psychiatry Society. P. Santosh is a member of EAGG and a member of Eunethydis. He has been the Principal Investigator on the following commercial trials: Sarizotan (Protocol Number Sarizotan/001/II/2015), GW Pharma (Protocol Number: GWND18064), Anavex Life Sciences Corp (Protocol Number: ANAVEX2-73-RS-002 & ANAVEX2-73-RS-003). He has also been on the advisory board and received funding from Acadia Pharmaceuticals. P. Santosh is also the co-inventor of the HealthTracker™ platform, a shareholder and its Chief Executive Officer. K.S. receives grant funding from the NIHR and UKRI. He was a member of both of the NICE ADHD Guideline Development Groups (CG72 (2008) & NG87 (2018). D.O. has received research funding from the NIHR, South London and Maudsley NHS Foundation Trust, Maudsley Health, the Medical Research Council, Barts Charity, Maudsley Charity, the Kavli Trust, Guy’s and St Thomas’s Charity and the Psychiatry Research Trust. He has received donations from British-Ukrainian Aid, Clinical Partners, the British Medical Association, UNICEF and Ukraine Charity for his humanitarian work. He has received or will receive royalties for publications from Hodder Arnold and Cambridge Scholars. D.O. is also a trustee of the Association for Child and Adolescent Mental Health, the Ukrainian Institute in London and the Ukrainian Medical Charity. J.D. and A.W. are supported by the Child and Adolescent Mental Health Services Digital Lab, and receive grant funding from UKRI and NIHR. K.S. receives grant funding from the NIHR and UKRI. He was a member of both of the NICE ADHD Guideline Development Groups (CG72 (2008) & NG87 (2018)). S.Y. was a member of the NICE ADHD Guideline Committee (NG72) and the NHS England ADHD Taskforce Experts in Criminal Justice System Group (2025). She is a trustee of the ADHD Foundation charity. S.Y. has received honoraria from Takeda, Janssen and Medice. She is the author of ACEv.2 and ACE+v.2 and receives income via her company from online training courses on the assessment and treatment of ADHD, which are hosted on the Teachable platform. All the other authors declare no conflicts of interest.