" Even though fully half of the roughly hundred thousand genes in the human organism are dedicated to the central nervous system, the genetic code simply cannot carry enough information to predetermine the infinite number of potential brain circuits. For this reason alone, biological heredity could not by itself account for the densely intertwined psychology and neurophysiology of attention deficit disorder. "

― Gabor Maté , Scattered Minds: The Origins and Healing of Attention Deficit Disorder