ADHD increase higher in economically disadvantaged children

The percentage of children diagnosed with attention-deficit/hyperactivity disorder (ADHD) is steadily increasing, especially for those whose families are less economically well off, according to recently released data from the National Health Interview Survey, 1998-
2009.

ADHD prevalence increased 7% to 9% overall, to 10% for children with family income less than 100% of the poverty level, and to 11% for those with family income between 100% and 199% of the poverty level, the National Center for Health Statistics (NCHS) report said.

According to the survey, ADHD prevalence trends varied by race and ethnicity. Differences between groups narrowed from 1998 through 2009; however, Mexican children had consistently lower ADHD prevalence than other racial or ethnic groups. Increases were greater (10%) in the Midwest and South than in other regions of the United States.

All ADHD-prevalence estimates were obtained from a table on the Centers for Disease Control and Prevention (CDC) Health Data Interactive Web site. Survey data are collected continuously throughout the year by the US Census Bureau for NCHS, a division of the CDC.

Surveyors interviewed respondents in their homes and sometimes through telephone follow-up calls. For sample child data, a responsible adult, usually a parent, responds to the survey questions as proxy for a sample child in households with children.

Report investigators said that tracking prevalence of ADHD is important because the disorder’s symptoms (ie, inattention, impulsive behavior, and hyperactivity) can cause lifetime difficulties in academic, family, and social settings. They also cautioned that data were based on parental reports and could be affected by recall bias, diagnostic bias, or willingness to report an ADHD diagnosis.

If anything, researchers pointed out, actual prevalence may be much higher than what was reported.

“One study that included clinical assessment of children for ADHD symptoms found that only one-half of children meeting the criteria for ADHD had received a diagnosis of ADHD or regular medication treatment,” researchers said. “For the present report, it was not possible to discern whether growing prevalence indicates a true change in prevalence or increased detection and diagnosis of ADHD. Nevertheless, the societal costs of ADHD-including those associated with medical, educational, and criminal justice resources-are large.”

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