The study estimates 3% of workers have ADHD
Adults with attention deficit hyperactivity disorder do 22 fewer days of work per year than people who do not have the condition, a study says.
The research, which looked at 7,000 workers in 10 countries, found an average of 3.5% had ADHD.
Writing in Occupational and Environmental Medicine, the Dutch team said workplace screening should be used to pick up people with the problem.
A UK expert backed the idea, but warned they should not be stigmatised.
People who have ADHD find it difficult to concentrate because they may be hyperactive, easily distracted, forgetful or impulsive.
It is commonly thought of as a childhood disorder, often picked up because of problems at school.
However, there are estimates that around two-thirds of those affected in childhood are still experiencing symptoms in adulthood.
More common in men
In the study, employed and self-employed workers aged 18 - 44 were screened for ADHD as part of the World Health Organisation World Mental Health Survey Initiative in Belgium, Colombia, France, Germany, Italy, Lebanon, Mexico, the Netherlands, Spain and the USA.
They were also asked about their performance at work in the last month.
Those results were extrapolated out to give annual figures.
Workers with ADHD were found to take an average of eight days off sick each year.
They also had, on average, 21 days where they did less work than they should have and 13 days where their work was of poorer quality - each of which was deemed to equate to half a day of lost performance.
ADHD was more prevalent in men and workers in developed rather than developing countries.
The study was carried out by a team who are part of a World Health Organization (WHO) research consortium at Harvard Medical School.
The team, led by Dr Ron de Graaf, said: "It might be cost-effective from the employer perspective to implement workplace screening programmes and provide treatment for workers with ADHD."
Professor Philip Asherson, an expert in adult ADHD at London's Institute of Psychiatry, said the condition did have an impact on people's timekeeping, their relationship with colleagues and the ability to focus on work.
He added: "ADHD should be included in general health screens, in the same way that people would screen for anxiety and depression. This is probably best done by GPs or occupational health departments.
"However, it's important that ADHD isn't stigmatised as many people with the condition can hold down jobs, or may be particularly good at certain tasks."