Stimulant treatment over 5 years: effects on growth.
OBJECTIVE
Long-term effects of psychostimulants on growth in height and in weight are investigated in children with attention-deficit/hyperactivity disorder.


METHODS
Participants were 79 children, 6 to 12 years of age, with attention-deficit/hyperactivity disorder, who were followed annually for up to 5 years, between the years 1993 and 1994 and 1998 and 1999. Annual height and weight measurements were standardized by age and gender using the 2000 Centers for Disease Control and Prevention Growth Charts for the United States and reported as z scores. For children taking stimulants throughout the previous school year, dose potency was standardized to methylphenidate in milligrams per kilogram per day. We used hierarchical linear modeling to investigate the influence of dose and duration of stimulant treatment on the rate of growth in height and weight.


RESULTS
Controlling for time since initiation of treatment, daily dose of stimulant medication was negatively associated with z scores for height (beta = -.11, SE = 0.03, p <.01) and for weight (beta = -.29, SE = 0.04, p <.01). Estimates based on the statistical model suggest that children receiving > or = 1.5 mg/kg/day methylphenidate will show diminished weight gain after 1 year; those receiving > or = 2.5 mg/kg/day methylphenidate will show diminished gains in height after 4 years.


CONCLUSIONS
Long-term use of high doses of stimulants during a period of 1 to 5 years is likely to have measurable effects on the rate of growth in school-age children with attention-deficit/hyperactivity disorder.
Charach
Alice
A
Department of Psychiatry, The Hospital for Sick Children, Toronto, Ontario, Canada. alice.charach@sickkids.ca
Figueroa
Max
M
Chen
Shirley
S
Ickowicz
Abel
A
Schachar
Russell
R
D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy*; D001827:Body Height / Q000187:drug effects; D000697:Central Nervous System Stimulants / Q000627:therapeutic use*; D002648:Child; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D006128:Growth / Q000187:drug effects*; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000627:therapeutic use*
D000697:Central Nervous System Stimulants; D008774:Methylphenidate