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Extended stimulant use does not reduce ADHD, stunts growth

Longitudinal analysis indicated associations between extended use of stimulant medications and shorter adult height but not symptom reduction.

“The [Multimodal Treatment Study] began as a 14-month randomized clinical trial to test hypotheses about four treatment strategies: medication management, behavior modification, their combination, or treatment-as-usual for a community comparison,” James M. Swanson, PhD, of University of California, Irvine, and colleagues wrote. “After the [randomized clinical trial], the [Multimodal Treatment Study] transitioned into an observational long-term follow-up, and analyses were performed to generate hypotheses for future studies. At 2, 3, and 8 years after baseline, [intention-to-treat] analyses of the randomly assigned groups were continued and indicated the initial symptom-related benefit and growth-related cost dissipated after the 14-month treatment-by-protocol phase.”

The observational long-term follow-up included 515 individuals diagnosed with ADHD and 258 individuals without the disorder. Treatment was assessed to age 18 years and naturalistic subgroups were established based on long-term use of stimulant use: consistent, inconsistent and negligible.

Parent and self-reported average symptom persistence was statistically significantly different between participants with ADHD and those without (P < .0001).

Comparisons of medication effects among participants with consistent, inconsistent and negligible stimulant use were not significant.

Participants with ADHD were 1.29 cm shorter than those without the disorder (P < .01).

Participants with consistent or inconsistent stimulant use were 2.55 cm shorter than those with negligible stimulant use (P < .0005).

Participants with consistent stimulant use were 2.36 cm shorter than those with inconsistent use (P < .04).

“The findings of the [Multimodal Treatment Study] suggest the following: childhood-onset ADHD is a chronic disorder with persistence of symptoms into adulthood; source discrepancy due to lower self-ratings than parent-ratings is manifested in early adulthood; and extended use of stimulant medication from childhood through adolescence is associated with suppression of adult height but is not associated with reduced symptom severity in adulthood,” the researchers concluded. – by Amanda Oldt

Disclosure: Swanson reports receiving research support, advisory board membership, speaker’s bureau membership, and/or consulting for Alza, Richwood, Shire, Celgene, Novartis, Celltech, Gliatech, Cephalon, Watson, CIBA, UCB, Janssen, McNeil and Lilly. Please see the study for a full list of relevant financial disclosures.