Whatever their foibles — door-slamming, grunting, excessive Snapchatting — teenagers are right about one thing: nobody understands them. This umbra of non-comprehension takes in not just parents, but doctors, psychologists, neuroscientists, social scientists, legal experts and educators.

There is surprisingly scant scientific research about the hazy period between childhood and adulthood in which adolescents exist. As an editorial in the journal Nature pointed out this month: “A modern healthcare system without a focus on the unique challenges of paediatrics or geriatrics would be unthinkable, yet there is no similar effort on behalf of adolescents.”

This is despite the fact that 10-24-year-olds now constitute a record quarter of the global population.