There is substantial overlap of attention-deficit/hyperactivity disorder
(ADHD) and learning disability (LD) in U.S. children between the ages of 6 and
17, according to an analysis of national survey data released by the Centers
for Disease Control and Prevention (CDC) in July.
The CDC's analyses were based on data collected in the 2004, 2005, and 2006
National Health Interview Survey (NHIS), a nationwide survey conducted by the
National Center for Health Statistics using a representative sample of the
noninstitutionalized civilian population. The data collected on almost all of
the children sampled were obtained via the direct questioning of a parent and
included demographic information about the child, diagnoses of health
conditions, use or non-use of special educational services and health care
services, and any medications they took.
The prevalence of having ADHD without LD was approximately 4.7 percent
among children aged 6 to 17. The prevalence of LD without ADHD was 4.9
percent. About 3.7 percent had both diagnoses concurrently, indicating a high
rate in the coexistence of both conditions in this population. The long-term
trends of diagnoses of ADHD and LD showed that, from 1997 to 2006, the overall
prevalence of LD remained more or less flat, but ADHD diagnoses had increased
over the decade (see chart).
Gender is a significant factor in the rates of both diagnoses. More boys
had the diagnosis of ADHD only, LD only, or both ADHD and LD than girls (see
chart). Adolescents (12 to 17 years of age) were more likely to be diagnosed
with each of the three types of diagnoses than younger children (6 to 11 years
of age). The report also noted an association between low birth weight and LD
regardless of co-existing ADHD but not between low birth weight and ADHD
Hispanic children were less likely than non-Hispanic black children and
non-Hispanic white children to have a diagnosis of ADHD (with or without LD).
Children covered by Medicaid had a higher rate of having a diagnosis of ADHD
only, LD only, or both, than children without insurance or with private
This report is helpful as it provides current "data on the prevalence
of ADHD and learning disabilities as actually diagnosed in a large
population," David Fassler, M.D., a child psychiatrist and a clinical
professor of psychiatry at the University of Vermont and secretary-treasurer
of APA, commented to Psychiatric News. The higher incidence of ADHD
diagnosis among adolescents between the ages of 12 and 17, he noted, is
probably attributable to several factors including "increased knowledge
about ADHD and improved access to appropriate health care and educational
In addition, children with either ADHD, LD, or both were more likely than
children with neither to have comorbid chronic medical conditions such as
cerebral palsy, muscular dystrophy, cystic fibrosis, sickle-cell anemia,
diabetes, arthritis, or heart disease. The prevalence of asthma, however, did
not differ among children with these diagnoses and those without it.
Both ADHD and LD present significant burdens on families, schools, and
health care systems. Children with ADHD only, LD only, and both had a greater
need for health care and special-educational services, including having
contacts with a medical specialist or a mental health professional, using
prescription medications, having four or more health care visits in the past
year, and receiving special-education services. The need was higher in
children with both ADHD and LD compared with those having only one of the
"As the report notes, it's been estimated that the annual societal
cost attributable to ADHD is in excess of $30 billion," said Fassler."
Hopefully the results of this study will further enhance awareness and
recognition of this common and treatable disorder."
"Diagnosed Attention Deficit Hyperactivity Disorder and
Learning Disability: United States, 2004-2006" is posted at<www.cdc.gov/nchs/data/series/sr_10/Sr10_237.pdf>.▪