Currently the medical community holds that the root cause of "hyperactivity" is injury to the brain, so the number of hyperactive children shouldn't rise because of environmental factors. But the number of parents who believe that their children are hyperactive and seek treatment for them clearly has risen as a result of environmental change.
目前醫界認為「分心過動症」肇因於腦部損傷，因此過動兒的發生率，不會因為環境的改變而增加，但是父母親認為孩子過份好動，帶孩子就診的比例，確實因環境的改變而增加。