Your child seems to behave in ways that resemble attention deficit hyperactivity disorder, but perhaps you're hesitant to explore the matter. After all, you can't help but think these may be age-appropriate behaviors or a perhaps a phase. So, maybe it's best to hold off on getting a formal diagnosis. Not so fast, cautions E. Mark Mahone, a child neuropsychologist, research scientist and the director of the department of neuropsychology at the Kennedy Krieger Institute in Baltimore.