Until recently, attention deficit hyperactivity disorder (ADHD) was thought to affect only school-age boys, that is, naughty boys who couldn’t sit still in class and were constantly getting into trouble. Today, the number of ADHD diagnoses is rapidly increasing across all age groups; Some of the largest increases are seen in young and middle-aged women.

The numbers are staggering. The Nuffield Trust, a think tank, says around two million people in England, or 4 per cent of the population, are thought to have ADHD. Its symptoms often overlap with other conditions thought to arise from the development of the brain, such as autism, dyslexia and ADHD. In total, 10 to 15 percent of children have attention and information processing patterns that fall into these categories.