Attention Deficit Hyperactivity Disorder (ADHD) may still be under-recognised and under-diagnosed in England despite recent increases in diagnosis, according to a study led by researchers at UCL, University of Liverpool and King's College London.
The research, published in The Lancet Regional Health Europe, found that while 1.19% of people in England had an ADHD diagnosis in their primary care record, recorded diagnosis rates were notably lower across all age groups compared with the international estimates of actual ADHD prevalence, which typically range between 3% and 5%.
This gap was especially large in older adults, with just 0.05% of men and women over the age of 65 diagnosed with ADHD.
The researchers say their findings show that while diagnosis rates for ADHD have increased substantially over the past decade for children and adults, recorded diagnoses of ADHD in England are still lower than the best available estimates of ADHD prevalence.
Rates of new ADHD diagnoses increased markedly after 2020 across most age groups. The highest rates were observed in boys under 18 years old, while increases among adults were particularly notable in women.
In contrast, diagnosis rates among adults aged 65 and over remained consistently low throughout the study period.
Lead author, Psychology Lecturer, Dr Amber John, who began the research at UCL before moving to the University of Liverpool, said: "The low rates observed in older adults don't necessarily mean that ADHD is uncommon in older age.
"Instead, they may reflect historical differences in recognition and access to diagnosis, particularly among generations who grew up before ADHD was widely recognised."
A major benefit to accurately understanding the incidence of ADHD across the population is in ensuring that appropriate services are in place.
Senior author Professor Joshua Stott (UCL Psychology & Language Sciences) said: "It is important that people are guided by the data.
"For nearly all age groups, while prevalence is still lower than expected in 2025, there was an increase in diagnoses of ADHD after 2020.
"This has relevance because health providers should take these changing diagnostic prevalences into account when planning services in support of people living with ADHD."
The authors of the new study, funded by the Medical Research Foundation and the British Academy, used data from more than 3.5 million people registered with GP practices in England in 2025 to estimate the proportion of people with a recorded ADHD diagnosis at this time.
They then compared this with published estimates of ADHD prevalence in the general population from international studies (which pulled together studies using multiple methods to estimate how common ADHD really is) and used data from more than 42 million patients in England to examine diagnostic trends in ADHD from 2000 to 2024.
Joint first author Dr Gavin Stewart, British Academy Research Fellow at the Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King's College London, said: "When we compared recorded ADHD diagnoses with published estimates of how common ADHD is in the population, we found a substantial gap across every age group.
"This gap was especially large in older adults, suggesting that many people may have gone unrecognised."
A previous UCL-led study that compared 30,029 adults across the UK with diagnosed ADHD and 300,390 participants without ADHD found that adults with ADHD have reduced life expectancies.
Professor Stott said: "When it comes to mid-life and late-life health outcomes in people with high ADHD traits, they tend to have increased rates of physical and mental health difficulties. Consequently, it is useful for services and clinicians to be aware that while many in this group probably don't have diagnoses, they may well have extra needs."
Study co-author Dr Georgia Pavlopoulou, Associate Professor at UCL and Neurodiversity Programmes Lead at Anna Freud, added: "Our findings suggest that ADHD is being under-recognised, challenging increasingly common narratives about overdiagnosis.
"The results also indicate that some groups who do not fit traditional stereotypes about ADHD, including older people, women and those from minoritised ethnic communities, may be particularly affected.
"To turn this evidence into action, we want to see services better resourced to provide culturally responsive, gender-informed and equitable support."
Study limitations
The authors note that ADHD was identified using diagnosis and prescription codes recorded in primary care data. As with all studies using routine healthcare records, it is possible that some diagnoses may have been misclassified.
Additionally, the international estimates for ADHD prevalence used for comparison in this study are based on meta-analyses synthesising findings from studies with varied definitions of ADHD and differing assessment methods. Estimates should therefore be viewed as benchmarks rather than precise estimates of true prevalence of ADHD in England.
The main analysis may slightly underestimate the true prevalence of recorded ADHD, because some diagnoses may not have been fully recorded.
