A world-first study led by UCL researchers, published in The British Journal of Psychiatry, analysed anonymised primary care data from 30,029 adults across the UK diagnosed with attention deficit hyperactivity disorder (ADHD).

They then compared this group with 300,390 participants without ADHD, who were matched by age, sex, and primary care practice.

The researchers found an apparent reduction in life expectancy for men with diagnosed ADHD of between 4.5 and 9 years, and between 6.5 and 11 years for women.

Senior author, Professor Josh Stott (UCL Psychology & Language Sciences), said, "It is deeply concerning that some adults with diagnosed ADHD are living shorter lives than they should.

"People with ADHD have many strengths and can thrive with the right support and treatment. However, they often lack support and are more likely to experience stressful life events and social exclusion, negatively impacting their health and self-esteem."

The study also found that fewer than one in nine adults with ADHD had been diagnosed—meaning that only a fraction of the total population of adults with ADHD could be studied.

Professor Stott added, "We know from studies of traits in the community and from studies of childhood diagnosis that the rate of ADHD in our sample is just a fraction of what it should be."

People with ADHD experience differences in the way they focus their attention. They often have high energy and an ability to focus intensely on what interests them. However, they may find it difficult to focus on mundane tasks.

This can lead to more impulsiveness, restlessness, and differences in planning and time management, which may make it harder to succeed at school and work, leading to longer-term challenges. ADHD is present from childhood and is increasingly recognised to persist in adults.

ADHD is under-treated in adults in the UK compared to in other high-income countries, and support is under-resourced.

This is the first time that researchers have estimated the life expectancy of UK adults diagnosed with ADHD.

However, they note that because ADHD often goes undiagnosed—especially in adults—the new research may overestimate the reduction in life expectancy experienced by people with ADHD on average.

Lead author, Dr Liz O'Nions (UCL Psychology & Language Sciences and Bradford Institute for Health Research), said, "Only a small percentage of adults with ADHD have been diagnosed, meaning this study covers just a segment of the entire community.

"More of those who are diagnosed may have additional health problems compared to the average person with ADHD. Therefore, our research may overestimate the life expectancy gap for people with ADHD overall, though more community-based research is needed to test whether this is the case."

At present, there is a lack of specialist services to support adults with ADHD in the UK.

For example, a previous national survey of adults aged 16–64 found that a third of those with ADHD traits were in receipt of medication or counselling for a mental health problem, compared to 11% of people without ADHD.

Nearly 8% of people who screened positive for ADHD reported that they had requested a particular mental health treatment in the past 12 months but had not received it, compared to only 1% of those who did not screen positive.

This suggests that adults with ADHD are presenting to services, but services are not equipped to support them, even though the impact of ADHD and the need to identify and treat it is recognised in NHS guidelines.

This is a leading concern, as treatment and support for ADHD are associated with better outcomes, such as reduced mental health problems and substance use.

Dr O'Nions said, "Although many people with ADHD live long and healthy lives, our finding that on average they are living shorter lives than they should indicates unmet support needs. It is crucial that we find out the reasons behind premature deaths so we can develop strategies to prevent these in future."

Study limitations

The study data meant that the researchers did not have information regarding the cause of death, so it was not possible to attribute years of lost life to different causes.

A lack of specialist services for adult ADHD assessment in the UK also means that diagnosed adults may overrepresent those who have co-occurring mental health and/or neurodevelopmental conditions, which could confound the results and lead to an overestimation of years of life lost.

The present findings may not generalise to other countries, time periods, or settings.

More information: Life expectancy and years of life lost for adults with diagnosed ADHD in the UK: a matched cohort study, The British Journal of Psychiatry (2025). DOI: 10.1192/bjp.2024.199