“Significant gaps” in ADHD research post 2020 hindering development of effective policy

New research from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s College London reveals a lack of reliable data tracking the prevalence and incidence of ADHD post-2020, resulting in significant gaps in an evidence base to develop realistic health policy, according to scientists.  

The research, which is the first systematic review of ADHD prevalence to be published since the start of the COVID-19 pandemic, highlighted the poor quality of studies available for inclusion. Despite this, the best quality data found no significant rise in the prevalence of ADHD. 

A total of 40 studies were included in this review. All included studies presented original data collected between January 2020 and February 2024 from the general global population. 

An analysis of the best quality data suggested that the rate of diagnosis of ADHD continues to vary internationally. In the USA, between 9.6 per cent and 10.5 per cent of children aged 3-17 years have been diagnosed¹, compared to 7.5 per cent of 288,248 children and emerging adults aged 1-24 years in Canada, and 3.2 per cent of 70,437 children aged 0-17 years in Sweden. 

Recent studies that suggested higher rates of ADHD diagnosis were of low quality, using only self-reporting surveys, or parent/teacher reported symptoms, not clinical diagnoses. 

Dr Alex Martin, Lecturer in Psychology at King’s IoPPN and the study’s first author said, “The media has been concerned about a ‘surge’ in ADHD diagnoses for several years. 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, but most of the research is too biased to draw conclusions from.   

“When data is not updated, or isn’t reliable, scientists cannot complete high quality research. This causes problems for healthcare policy makers internationally and means that services which are already under pressure may encounter increased demand without receiving additional support”. 

Anecdotal reports suggest that the UK has seen an unprecedented rise in the number of children and adults seeking support for ADHD. The demand has exacerbated pressures on public services and increased already significant backlogs of people awaiting assessment. In the UK, a survey by the Petitions Committee in 2023 found that approximately 1 in 4 of those who responded face delays of up to two years for an assessment, while 1 in 10 are facing waits that exceed two years. 

Dr Samantha Brooks, post-doctoral researcher at King’s College London and the study’s senior author said, “Between January and May 2024, there were 25,080 media articles published on ADHD compared to 5,775 articles in the same period in 2014, with publications rising notably in 2020 and peaking in early 2023. 

“What we cannot account for, which is perhaps the biggest outstanding question, is why there has been an unprecedented increase in the number of people seeking help for ADHD.” 

Professor Philip Shaw, Director of the King’s Maudsley Partnership for Children and Young People said, “This study presents us with a puzzle. How can the ‘true’ rate of ADHD not be increasing despite rising demand for ADHD assessments?  It could well be that increased awareness of ADHD is leading more people to seek assessment, but only good quality and properly conducted research can tell us the cause.” 

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. 

Read more:

The changing prevalence of ADHD? A systematic review (DOI10.1016/j.jad.2025.119427) (Alex F Martin, G James Rubin, M Brooke Rogers, Simon Wessely, Neil Greenberg, Charlotte E Hall, Angie Pitt, Poppy

Ellis Logan, Rebecca Lucas, Samantha K Brooks) was published in the Journal of Affective Disorders. 

1. The rate of diagnosis of ADHD in children is between 9.6% (of n=26,422) and 10.5% (of n=37,609) of children aged 3-17 years in the USA ((Li et al., 2023a) and (Li et al., 2023b), respectively) 
2. UK prevalence is reported to be 1.8 per cent of male and 0.4 per cent of female children as reported in a 2018 study 

1. McKechnie DGJ, O’Nions E, Dunsmuir S, Petersen I. Attention-deficit hyperactivity disorder diagnoses and prescriptions in UK primary care, 2000–2018: population-based cohort study. BJPsych Open. 2023;9(4):e121. doi:10.1192/bjo.2023.512 

About King’s College London and the Institute of Psychiatry, Psychology & Neuroscience  

King’s College London is amongst the top 35 universities in the world and top 10 in Europe (THE World University Rankings 2023), and one of England’s oldest and most prestigious universities.  

With an outstanding reputation for world-class teaching and cutting-edge research, King’s maintained its sixth position for ‘research power’ in the UK (2021 Research Excellence Framework).  

King’s has more than 33,000 students (including more than 12,800 postgraduates) from some 150 countries worldwide, and some 8,500 staff. The Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s is a leading centre for mental health and neuroscience research in Europe. It produces more highly cited outputs (top 1% citations) on psychiatry and mental health than any other centre (SciVal 2021), and on this metric has risen from 16th (2014) to 4th (2021) in the world for highly cited neuroscience outputs. In the 2021 Research Excellence Framework (REF), 90% of research at the IoPPN was deemed ‘world leading’ or ‘internationally excellent’ (3* and 4*). World-leading research from the IoPPN has made, and continues to make, an impact on how we understand, prevent and treat mental illness, neurological conditions, and other conditions that affect the brain. 

www.kcl.ac.uk/ioppn | Follow @KingsIoPPN on Twitter, Instagram, Facebook and LinkedIn 

About the National Institute for Health and Care Research (NIHR) 

The mission of the National Institute for Health and Care Research (NIHR) is to improve the health and wealth of the nation through research. We do this by: 

• Funding high quality, timely research that benefits the NHS, public health and social care; 
• Investing in world-class expertise, facilities and a skilled delivery workforce to translate discoveries into improved treatments and services; 
• Partnering with patients, service users, carers and communities, improving the relevance, quality and impact of our research; 
• Attracting, training and supporting the best researchers to tackle complex health and social care challenges; 
• Collaborating with other public funders, charities and industry to help shape a cohesive and globally competitive research system; 
• Funding applied global health research and training to meet the needs of the poorest people in low and middle income countries. 

NIHR is funded by the Department of Health and Social Care. Its work in low and middle income countries is principally funded through UK international development funding from the UK government.