Attention deficit hyperactivity disorder, or ADHD, could be costing the UK billions of pounds a year, according to a new report that says awareness of the condition in adults in particular is very poor and many people go undiagnosed and untreated.

According to the thinktank Demos, ADHD is a major socio-economic burden. The costs to the nation of the disorder in adults who are unable to work or hold down a full-time job are high.

“Too many people with the condition are going through life without receiving the diagnosis or support they need to be happy and fulfilled, and to make the most of their talents,” says its report.

“Many people with the condition suffer immensely in all areas of their lives, including education, work, relationships and more, with implications for their friends and family, wider society and the public purse too.”

Demos is calling for the government to launch an awareness campaign, to make adult ADHD more visible to the public and get help for those affected. It is thought that 5% of children and 2.5% of adults are affected by the disorder, although Demos says this could be an underestimate.

Most people think of ADHD as a disorder of childhood, which causes children – most often boys – to become hyperactive and unable to focus and learn in class. But 65% of children with the condition do not shrug it off as they become adults. They can end up in low paid jobs, if any, and may have difficulty forming relationships with people in and outside of the workplace.

“Evidence suggests that adults with ADHD are less likely to be in full-time, paid work than those without the condition, and that their on-the-job productivity may also be reduced. This has implications for individuals, employers and the state, as a result of reduced tax-take and increased expenditure on welfare benefits,” says the report.

It talks of lost talent and opportunities. “People with ADHD can be creative, energetic and dynamic,” it says. But too many people go through life without the support they need.”