Childhood as an idea may have its origins in the 18th century, when philosopher Jean-Jacques Rousseau described it as a brief period of sanctuary before the hardships of adult life. Before then, art had been in line with the spirit of the times, depicting children as little adults. Historically, too, we can track the change in attitudes. Enforced child labour, for example, gradually became unacceptable.

Even now, however, children are exposed early in life to disadvantage, distress, repeated neglect and abuse, leading to poorer health, learning and social functioning. Early adversity can put individuals on a lifelong trajectory of increasing risk. Fortunately, we know quite a lot about how this happens. Remarkably, we also know that some adversity is not linked to poverty or deprivation, and that there are resilient children who prosper and thrive despite the harsh and often damaging realities.