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

Abstract

OBJECTIVE\nTo estimate long-term stimulant treatment associations on standardized height, weight and BMI trajectories from childhood to adulthood in the Multimodal Treatment Study of Attention-Deficit/Hyperactivity Disorder (MTA).\n\n\nMETHOD\nOf 579 children with DSM-IV ADHD-Combined Type at baseline (ages 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 cases starting stimulants prior to MTA entry (N=211, 39%). Height and weight growth trajectories were calculated for each subgroup.\n\n\nRESULTS\nHeight z-scores trajectories differed among subgroups (F=2.22, P<0.0001) and by stimulant use prior to study entry (F=2.22, P<0.001). The subgroup x assessment interaction was significant (F=2.81, P<0.0001). Paired comparisons revealed significant subgroup differences at end-point: Consistent 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<0.0172), 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 pounds, P<0.0001).\n\n\nCONCLUSION\nCompared 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 of adult height, and an increase in weight and BMI.