These data, which are based on a nationally representative survey, show that the pediatric use of stimulants has continued to grow at the same pace since the mid-1990s. This relatively slow growth is in sharp contrast to the rapid increase that occurred between the mid-1980s to the mid-1990s. However, the overall growth rate for children under age 19 mask important changes that have occurred within different age groups. In particular, stimulant use increased among 13–18 year olds in the period 2002–2008, with use rates converging with those of 6–12 year olds. In contrast, use has declined in preschoolers.
Children from racial and ethnic minority groups have increased the use of stimulants, which, however, remains lower than among non-Hispanic White children. In addition, while females tend to use more stimulants now than ten years ago, boys still retain a 3-fold higher utilization rate, which is consistent with the higher prevalence of ADHD in males (6
). Finally, significant differences by U.S. geographical location persist, with the West having significantly lower use.
If one compares these estimated rates of utilization of stimulant medication with the estimated prevalence of the ADHD diagnosis in the community (6
), it appears that most children diagnosed with ADHD are not treated with stimulants. This may not be unexpected when considering that about half of those diagnosed present only with mild symptoms (6
), and that other treatments, including both psychosocial and non-stimulant medications, are available. In the absence of biological markers for ADHD, the validity of community diagnoses is uncertain, and the MEPS database does not allow diagnostic validity to be examined, even though it represents an ecologically valid estimate of the prevalence of community diagnoses. In any case, the data show that stimulant use is higher in children with significant functional impairment, as indicated by the Columbia Impairment Scale ( and ), further supporting the notion that these medications tend to be prescribed for the more severe forms of the disorder.
The significant increase in stimulant utilization among racial and ethnic minorities and low income families indicates an increased recognition of ADHD and acceptance of its pharmacological treatment also by the groups where disparities in mental health services have traditionally existed. But the persistence of differences in use among racial and ethnic groups also indicates that social and cultural factors continue to play a significant role in ADHD treatment utilization. Parents of Hispanic and African American children are less likely to report ADHD than parents of white children, and these differences were not accounted for by health or socioeconomic variables, such as birthweight, income, or insurance coverage (17
The continuous, steep increase in stimulant utilization among adolescents likely reflects the recent realization that ADHD tends to persist in puberty, causing significant functional impairment (18
). Data from the U.K. document a steep increase in ADHD medication prescribing for youth over the years 1999–2006, thus indicating that this phenomenon is not limited to the U.S. (20
). The increasing use in this age group does little to assuage the concerns raised about the potential for misuse and diversion of these medications (11
An age group in which use has remained extremely low, and has actually declined over the twelve-year period 1996–2008, is that of the preschoolers (). In early 2000, much concern was raised about use of stimulants by young children (21
). Subsequently, a controlled clinical trial showed that methylphenidate is effective in preschoolers with ADHD, but also causes more adverse effects than in school-age children (22
). These data indicate that, in clinical practice, stimulants are seldom used in children under age 6, and the trend has been towards even lower use.
The significant differences in use across geographical areas of the U.S. are consistent with previous reports (24
), and document a substantial variability in the approach to ADHD, which likely reflects differences in treatment preferences across the country that deserve further inquiry. Differences in health care organization and delivery in the West compared with the rest of the U.S. may account for some of the observed discrepancy. However, the lower use of stimulant medication in the West does not seem to be paralleled by a lower pediatric use of other psychiatric medications, such as antidepressants (25
Several methodological limitations must be taken into account when interpreting these data. Self-report surveys such as the MEPS rely on the responders’ ability and willingness to accurately recall information. Recall and reporting biases could result in under reporting and consequently underestimating use. While the MEPS is designed to make nationally representative estimates using probability-based sampling, the adjustments made for non-response may not completely eliminate the potential for non-response bias. The MEPS does not include sufficient information for determining the validity of the reported diagnosis of ADHD. Yet, the validity of the MEPS data is supported by their consistency with data on drug expenditures from other sources (26
). Another limitation is the lack of detail and statistical power in the database regarding non-stimulants or the combined use of medications in children, a practice that has become increasingly common (27
). However, based on available data, it appears that the proportion of atomoxetine users is small and has decreased, while most children using clonidine or guanfacine are also prescribed stimulants.
In conclusion, these data document an overall slow and constant increase over the last 12 years in stimulant medication utilization by children in the U.S., but with a steep growth in adolescents, no statistically significant change in children age 6–12 years, and a decline in preschoolers. Important variations in use related to racial/ethnic background and geographical location persist, thus indicating substantial heterogeneity in the approach to ADHD in the community.