"Despite concerns that the rate of ADHD is on the rise, the national prevalence of ADHD among American children is not clear and has been estimated at anywhere from 2% to 26%.

The researchers aimed to use a national sample with DSM-IV-based diagnostic criteria to estimate the prevalence of ADHD in American children and also to determine whether the prevalence, recognition, and treatment varied by socioeconomic group.

To determine whether the child met the criteria for inattention, the caregiver was asked if their child had difficulty concentrating, avoided activities requiring long periods of attention, was very disorganized, omitted things that were necessary for schoolwork, had trouble finishing tasks, forgot what they were supposed to do, made mistakes that were careless in nature, did not listen when people were talking to them, or started things and did not finish them.

To determine whether the child met the criteria for hyperactivity/impulsiveness, the caregiver was aksed if their child was overactive, seemed always on the go and driven by a motor, was fidgety or restless, left their seat when seating was expected, climbed and ran about when they were not supposed to, talked a lot and interrupted other people, made more noise than other children during an activity, butted in on what other people were doing, or had trouble waiting for their turn. The caregivers were asked if this behavior was seen at home and also at school.

8.7% of the children (equivalent to 2.4 million children nationwide) met the criteria for having ADHD in the year prior to the survey. Hispanics were less likely than whites to meet the criteria, and boys were more likely than girls to meet the criteria, although girls with ADHD were less likely to have their disorder identified.

DSM-IV–diagnosed ADHD is prevalent in American children, especially among poorer children, which needs to be further investigated. Second, less than half of the children who met the criteria for DSM-IV ADHD had their condition diagnosed or treated, "suggesting that some children with clinically significant inattention and hyperactivity may not be receiving optimal attention." Finally, poorer children were least likely to receive medication, which "warrants further investigation and possible intervention."

Arch Pediatr Adolesc Med. 2007;161:857-864