Jake,* aged 10, is referred to an attention deficit hyperactivity disorder (ADHD) service because of marked inattentiveness and aggressive outbursts at school and at home. Completed screening questionnaires indicate inattention and impulsivity with rather less hyperactivity. His teacher points out that he can focus very well on tasks of his own choosing, but it is very difficult to get him to concentrate on class work. He is often out of his seat in class and is generally restless. At home, he has terrible tempers, and is angrily impatient when he has to transition from one activity or situation to another and furious when the day has not turned out as originally planned. He will go on for days on end to his parents about some idea or demand and generally seems to have a rigid style of thinking: ‘as far as he’s concerned everything is black and white’.