I still remember the first time I treated a child with attention deficit hyperactivity disorder (ADHD).

Back then, around two decades ago, the condition was considered rare and GPs seldom came across it. But the moment I did, the symptoms were unmistakable. The boy, no more than 11 years old, frankly, was a nightmare.

He wouldn’t sit still in school, he wouldn’t sleep, and he was disruptive at home. I can vividly recall his mother’s stress. She worried he would never live a normal life – get a degree, hold down a job or learn to drive.

How things change. Once seen primarily as a disorder that caused children to be disruptive, ADHD is increasingly associated with middle-aged, middle-class woman struggling to focus at work.

Celebrities have led the way. Actress Gwyneth Paltrow, 53, has said her daughter’s diagnosis led her to get tested. ‘I thought, oh my God, I have this too,’ she revealed a few years back.