THE CASE

Your first patient of the morning is brought in by his parents for evaluation of school problems. He has always been described as “on the go.” When he was 4 years old, a preschool teacher expressed concern that his activity level at times limited play with other children. Now, in the middle of second grade, he is underachieving and not keeping up with either reading or mathematics. His teacher reports that he fidgets constantly and cannot keep his hands off other children. Friendships are limited and not sustained. His teacher suggested that his paediatrician should be asked whether he has attention deficit hyperactivity disorder.

Background

Attention deficit hyperactivity disorder (ADHD) is among the most common neurodevelopmental disorders in children.1 Its hallmarks are hyperactivity, impulsiveness, and inattention beyond the norm for a child's age (box).2

The disorder is frequently diagnosed in children with behavioural problems or in those who underachieve at school.3 Although the diagnosis is reliable if made by a standardised approach, concerns about the validity of the disorder often arise.4 At present there is no biological marker that clearly identifies affected children. Furthermore, it is unclear whether the disorder is unique or merely one end of the continuum of age appropriate behaviour. 5 6

You wonder how frequently academic difficulties or disruptive behaviours in a child …