Erratic Work Performance

Researchers also found that ADHD was more common among men than women, more common among blue-collar workers than white-collar professionals, and more common in developed than developing countries (such as Mexico, Lebanon, and Columbia). Age did not appear to be a factor.

Of the ADHD adults surveyed, very few of the diagnosed patients said they had received any treatment for ADHD in the prior year and were mainly American and Dutch respondents and of those, few received any treatment at all in previous years. Specifically, 3% of the Dutch workers and 13% of the U.S. workers received any treatment for their ADHD.

Kessler noted: "While surveying mental disorders around the world, we've interviewed close to 200,000 people in almost 30 countries, and we're discovering that an enormous number of adult workers -- more than 3 percent on average -- have untreated adult ADHD"

The report showed that besides the 22 fewer days ADHD adults worked, there was an average of more than eight days where ADHD adults said they simply were unable to carry out routine tasks, and nearly 14 days of reduced quality in the work they produced.

"The fact is that adult ADHD hasn't been on people's radar screens," said Kessler. "The feeling was that somehow magically when kids with ADHD grow up they grow out of it. But this survey shows that this is not the case."