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 ties or exacerbate preexisting mild to moderate ties. Method: Ninety-one children with attention-deficit hyperactivity disorder, with and without comorbid ties (excluding severe ties 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 ties developed in 19.6% of the subjects without preexisting ties 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 ties was observed in 33% of subjects with preexisting ties 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 ties than the placebo in children with or without preexisting (mild to moderate) ties.