“Of all environments, the one that most profoundly shapes the human personality is the invisible one: the emotional atmosphere in which the child lives during the critical early years of brain development. The invisible environment has little to do with parenting philosophies or parenting style. It is a matter of intangibles, foremost among them being the parents’ relationship with each other and their emotional balance as individuals. These, too, can vary significantly from the birth of one child to the arrival of another. Psychological tension in the parents’ lives during the child’s infancy is, I am convinced, a major and universal influence on the subsequent emergence of ADD. We will return to it in later chapters.”