A study that followed more than 500 children with attention-deficit/hyperactivity disorder (ADHD) into adulthood, found that extended use of stimulant medication was linked with suppressed adult height but not with reduced symptoms of ADHD.
The findings suggest that short-term treatment of ADHD with stimulant medication is well justified by benefits that outweigh costs, but long-term treatment may be associated with growth-related costs that may not be balanced by symptom-related benefits.
“The most recently published guidelines (American Academy of Pediatrics, 2011) recommend expanding the diagnosis and treatment beyond school-aged children and using stimulant medication as first-line treatment for adolescents as well as school-aged children,” wrote the authors of study. “Since this would increase the average duration of treatment and cumulative ME dose of medication in some individuals, the findings suggest growth-related costs may increase.”
Background: The Multimodal Treatment Study (MTA) began as a 14-month randomized clinical trial of behavioral and pharmacological treatments of 579 children (7–10 years of age) diagnosed with attention-deficit/hyperactivity disorder (ADHD)-combined type. It transitioned into an observational long-term follow-up of 515 cases consented for continuation and 289 classmates (258 without ADHD) added as a local normative comparison group (LNCG), with assessments 2–16 years after baseline.
Methods: Primary (symptom severity) and secondary (adult height) outcomes in adulthood were specified. Treatment was monitored to age 18, and naturalistic subgroups were formed based on three patterns of long-term use of stimulant medication (Consistent, Inconsistent, and Negligible). For the follow-up, hypothesis-generating analyses were performed on outcomes in early adulthood (at 25 years of age). Planned comparisons were used to estimate ADHD-LNCG differences reflecting persistence of symptoms and naturalistic subgroup differences reflecting benefit (symptom reduction) and cost (height suppression) associated with extended use of medication.
Results: For ratings of symptom severity, the ADHD-LNCG comparison was statistically significant for the parent/self-report average (0.51 ± 0.04, p < .0001, d = 1.11), documenting symptom persistence, and for the parent/self-report difference (0.21 ± 0.04, p < .0001, d = .60), documenting source discrepancy, but the comparisons of naturalistic subgroups reflecting medication effects were not significant. For adult height, the ADHD group was 1.29 ± 0.55 cm shorter than the LNCG (p < .01, d = .21), and the comparisons of the naturalistic subgroups were significant: the treated group with the Consistent or Inconsistent pattern was 2.55 ± 0.73 cm shorter than the subgroup with the Negligible pattern (p < .0005, d = .42), and within the treated group, the subgroup with the Consistent pattern was 2.36 ± 1.13 cm shorter than the subgroup with the Inconsistent pattern (p < .04, d = .38).
Conclusions: In the MTA follow-up into adulthood, the ADHD group showed symptom persistence compared to local norms from the LNCG. Within naturalistic subgroups of ADHD cases, extended use of medication was associated with suppression of adult height but not with reduction of symptom severity.
James M Swanson, L Eugene Arnold, Brooke SG Molina, Margaret H Sibley, Lily T Hechtman, Stephen P Hinshaw, Howard B Abikoff, Annamarie Stehli, Elizabeth B Owens, John T Mitchell, Quyen Nichols, Andrea Howard, Laurence L Greenhill, Betsy Hoza, Jeffrey H Newcorn, Peter S Jensen, Benedetto Vitiello, Timothy Wigal, Jeffery N Epstein, Leanne Tamm, Kimberly D Lakes, James Waxmonsky, Marc Lerner, Joy Etcovitch, Desiree W Murray, Maximilian Muenke, Maria T Acosta, Mauricio Arcos-Burgos, William E Pelham, Helena C Kraemer