Do typical clinical doses of methylphenidate cause tics in children treated for attention-deficit hyperactivity disorder?
OBJECTIVE
To determine whether typical clinical doses of methylphenidate (MPH) cause tics or exacerbate preexisting mild to moderate tics.


METHODS
Ninety-one children with attention-deficit hyperactivity disorder, with and without comorbid tics (excluding severe tics and Tourette's syndrome), were randomly assigned to receive MPH or a placebo in a 1-year prospective study. The target dose was titrated to balance behavior change and side effects. Parents and teachers were the observers.


RESULTS
Crossover from the placebo to MPH was common because of poor behavioral response. One MPH-treated subject dropped out; the final MPH group had 72 subjects; the placebo group, 18. The average dose of MPH was 0.5 mg/kg twice daily. Clinically significant tics developed in 19.6% of the subjects without preexisting tics receiving MPH and in 16.7% of those receiving the placebo (Fisher exact test, p = .59, not significant; relative risk = 1.17, confidence interval = 0.31-4.40). Deterioration of tics was observed in 33% of subjects with preexisting tics receiving MPH and in 33% of those receiving the placebo (Fisher exact test, p = .70, not significant; relative risk = 1.0, confidence interval = 0.40-1.85).


CONCLUSIONS
Doses of MPH based on the typical clinical titration procedure did not produce significantly more tics than the placebo in children with or without preexisting (mild to moderate) tics.
Law
S F
SF
Department of Psychiatry, Hospital for Sick Children, Toronto.
Schachar
R J
RJ
D001289:Attention Deficit Disorder with Hyperactivity / Q000150:complications / Q000188:drug therapy*; D000697:Central Nervous System Stimulants / Q000009:adverse effects*; D002648:Child; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000009:adverse effects*; D013981:Tic Disorders / Q000139:chemically induced* / Q000150:complications
D000697:Central Nervous System Stimulants; D008774:Methylphenidate