My six-year-old grandson suddenly ran into the street without looking left and right (or right and left if you prefer). I warned him, ‘Be careful, because you have only one life!’ He answered, ‘No, Grandpa, you have four lives. First you are a child, then a schoolboy, then a father and then a grandfather’. We know that these ‘lives’ transition smoothly one into another. The same goes for attention deficit hyperactivity disorder, where there is heterotypic continuity. But, we also discriminate between preschoolers, schoolchildren, adolescents and adults in scientific research and treatment protocols.