“The rate of diagnosis of attention deficit hyperactivity disorder among children has nearly doubled in the past two decades. Rates of A.D.H.D. diagnoses also vary considerably across states, with nearly three times as many children getting the diagnosis in Kentucky (where one in five children are said to have the condition) as in Nevada. More than 5 percent of all children in the United States now take an A.D.H.D. medication. All this raises the question of whether the disease is being overdiagnosed.” That description of the issues surrounding the diagnosis and medicating of A.D.H.D. probably sounds pretty familiar. But here’s a stat that might surprise you. “Rates of A.D.H.D. diagnosis and treatment were 34 percent higher among children born in August than among children born in September in states with a Sept. 1 school entry-age cutoff.” Three health policy researchers in the NYT on a new study that raises questions about age, maturity and overdiagnosis. The Link Between August Birthdays and A.D.H.D.