Little is known about the effects of adult attention deficit hyperactivity disorder (ADHD) on work performance or accidents-injuries.

A survey was administered in 2005 and 2006 to employees of a large manufacturing firm to assess the prevalence and correlates of adult ADHD. Respondents (4140 in 2005, 4423 in 2006, including 2656 in both surveys) represented 35–38% of the workforce. ADHD was assessed with the World Health Organization (WHO) Adult ADHD Self-Report Scale (ASRS), a validated screening scale for DSM-IV adult ADHD. Sickness absence, work performance and workplace accidents-injuries were assessed with the WHO Health and Work Performance Questionnaire (HPQ).

The estimated current prevalence (standard error) of DSM-IV ADHD was 1.9% (0.4). ADHD was associated with a 4–5% reduction in work performance (χ12=9.1, p=0.001), a 2.1 relative-odds of sickness absence (χ12=6.2, p=0.013), and a 2.0 relative-odds of workplace accidents-injuries (χ12=5.1, p=0.024). The human capital value (standard error) of the lost work performance associated with ADHD totaled US$4336 (676) per worker with ADHD in the year before interview. No data were available to monetize other workplace costs of accidents-injuries (e.g. destruction of equipment). Only a small minority of workers with ADHD were in treatment.

Adult ADHD is a significantly impairing condition among workers. Given the low rate of treatment and high human capital costs, in conjunction with evidence from controlled trials that treatment can reduce ADHD-related impairments, ADHD would seem to be a good candidate for workplace trials that evaluate treatment cost-effectiveness from the employer's perspective.