Trajectories of Growth Associated With Long-Term Stimulant Medication in the Multimodal Treatment Study of Attention-Deficit/Hyperactivity Disorder

Abstract

To estimate long-term stimulant treatment associations on standardized height, weight, and body mass index trajectories from childhood to adulthood in the Multimodal Treatment Study of Attention-Deficit/Hyperactivity Disorder (MTA). Of 579 children with DSM-IV ADHD-combined type at baseline (aged 7.0-9.9 years) and 289 classmates (local normative comparison group [LNCG]), 568 and 258 respectively, were assessed 8 times over 16 years (final mean age= 24.7). Parent interview data established subgroups with self-selected Consistent (n= 53, 9%), Inconsistent (n= 374, 66%), and Negligible (n= 141, 25%) stimulant medication use, as well as patients starting stimulants prior to MTA entry (n= 211, 39%). Height and weight growth trajectories were calculated for each subgroup. Height z scores trajectories differed among subgroups (F= 2.22, p< .0001) and by stimulant use prior to study entry (F= 2.22, p< .001). The subgroup-by-assessment interaction was significant (F= 2.81, p< .0001). Paired comparisons revealed significant subgroup differences at endpoint: Consistent was shorter than Negligible (-0.66 z units /-4.06 cm /1.6 inches, t=-3.17, p< 0.0016), Consistent shorter than Inconsistent (-0.45 z units /-2.74 cm /-1.08 inches, t=-2.39, p< .0172), and the Consistent shorter than LNCG (-0.54 z units/+3.34 cm/ 1.31 inches, t=-3.30, p< 0.001). Weight z scores initially diverged among subgroups, converged in adolescence, and then diverged again in adulthood when the Consistent outweighed the LNCG (+ 3.561 z units /+7.47 kg /+16.46 lb, p< .0001). Compared with those negligibly medicated and the LNCG, 16 years of consistent stimulant treatment of children with ADHD in the MTA was associated with changes in height trajectory, a reduction in adult height, and an increase in weight and body mass index. Multimodal Treatment Study of Children With Attention Deficit and Hyperactivity Disorder (MTA); https://clinicaltrials.gov/; NCT00000388.