Life expectancy and years of life lost for adults with diagnosed ADHD in the UK: matched cohort study

Background Nearly 3% of adults have attention-deficit and hyperactivity disorder (ADHD), although in the UK, most are undiagnosed. Adults with ADHD on average experience poorer educational and employment outcomes, worse physical and mental health and are more likely to die prematurely. No studies have yet used mortality data to examine the life expectancy deficit experienced by adults with diagnosed ADHD in the UK or worldwide. Aims This study used the life-table method to calculate the life-expectancy deficit for people with diagnosed ADHD using data from UK primary care. Method A matched cohort study using prospectively collected primary care data (792 general practices, 9 561 450 people contributing eligible person-time from 2000-2019). We identified 30 039 people aged 18+ with diagnosed ADHD, plus a comparison group of 300 390 participants matched (1:10) by age, sex and primary care practice. We used Poisson regression to estimate age-specific mortality rates, and life tables to estimate life expectancy for people aged 18+ with diagnosed ADHD. Results Around 0.32% of adults in the cohort had an ADHD diagnosis, similar to 1 in 9 of all adults with ADHD. Diagnoses of common physical and mental health conditions were more common in adults with diagnosed ADHD than the comparison group. The apparent reduction in life expectancy for adults with diagnosed ADHD relative to the general population was 6.78 years (95% CI: 4.50 to 9.11) for males, and 8.64 years (95% CI: 6.55 to 10.91) for females. Conclusions Adults with diagnosed ADHD are living shorter lives than they should. We believe that this is likely caused by modifiable risk factors and unmet support and treatment needs in terms of both ADHD and co-occurring mental and physical health conditions. This study included data from adults with diagnosed ADHD; the results may not generalise to the entire population of adults with ADHD, the vast majority of whom are undiagnosed.