Employed adults with attention deficit hyperactivity disorder do 22 fewer days of work per year on average than peers without the disorder, according to an article published online May 26 by the journal Occupational and Environmental Medicine.

The WHO (World Health Organization) World Mental Health Survey Initiative evaluated the prevalence and effects of adult attention deficit hyperactivity disorder in Belgium, Colombia, France, Germany, Italy, Lebanon, Mexico, the Netherlands, Spain and the United States.

More than 7,000 employed and self-employed workers aged 18 to 44 years were screened for the disorder as part of the World Health Organization World Mental Health Survey Initiative. They were also asked about their performance at work in the last month.

On average, 3.5 per cent of workers had the disorder; it was more prevalent in men and workers in developed compared with developing countries.

People with the disorder were found to lose 22.1 days of work per year compared with other workers. This was made up of 8.4 days when they were unable to work or carry out normal activities, plus 21.7 days of reduced work quantity and 13.6 days of reduced work quality.

So much work is apparently being lost that the researchers recommend employers consider screening staff for the disorder and providing treatment for those affected as a cost-effective measure for their businesses.