Prevalence of Drug Therapy for ADHD

Abstract

Source: LeFever GB, Kawson KV, Morrow AL. The extent of drug therapy for attention deficit-hyperactivity disorder among children in public schools. Am J Public Health. 1999:89;1359–1364.The authors of this study determined the prevalence of medication use for attention deficit-hyperactivity disorder (ADHD) in 2 school districts in southeastern Virginia. Students enrolled in grades 2 through 5 in school districts in city A (n = 5,767 students) and city B (n = 23,967 students) were included. Children in non-graded special education placements were excluded. About one third of the children in city B were members of military families. Information was obtained from school health databases from the 2 school districts and confirmed by a nurse research assistant who visited each school. The proportion of students receiving ADHD medication was similar in both cities (8% and 10%) and was 2 to 3 times higher than the expected rate of ADHD based on prior studies. Medication was used by 3 times as many boys as girls and by twice as many white students as black students. Medication use increased with years in school so that by fifth grade 18% to 20% of white boys were receiving ADHD medication. Being young for one’s grade was positively associated with medication use (p<.01). In city B, military children were more likely than civilian children to take ADHD medication during school hours (p<.02). These findings suggest that criteria for diagnosis of ADHD vary substantially across US populations, with potential over-diagnosis and overtreatment of ADHD in some groups of children.The 8 to 10% rate of medication use at school for ADHD by public elementary school students reported by LeFever et al is approximately 2-fold higher than previously published data.1,2 Based on findings of differences in medication use by gender and ethnicity, the authors suggested that variation within a region in ADHD labeling and treatment may exist. Boys were 3 times more likely to receive medications than girls, a finding that is consistent with national data suggesting that boys are diagnosed with ADHD at a rate 3-fold higher than girls.3 As has been previously reported, military children were more likely than civilian children to be diagnosed with ADHD.4 However, it is perplexing why a 2-fold difference in medication use by ethnicity should exist. This suggests differences in access to care, identification, acceptability of medication use for ADHD, and/or true differences in prevalence of ADHD according to ethnicity. Future studies are needed to corroborate this finding and to elucidate the reasons. Finally, the authors concluded that the high prevalence of medication use for ADHD suggests that ADHD may be overdiagnosed and overtreated in some groups of children. However, it is not possible to substantiate this conclusion from their data without knowing the overall prevalence of ADHD in this group and the proportion of children who receive medications, including those who receive medications during non-school hours.