METHYLPHENIDATE DISCONTINUATION AND REINITIATION DURING LONG-TERM TREATMENT OF CHILDREN WITH TOURETTES DISORDER AND ATTENTION-DEFICIT HYPERACTIVITY DISORDER - A PILOT-STUDY

The purpose of this study was to assess the effect of long-term treatment with methylphenidate (MPH) on tie symptom frequency and severity. Five boys, ages 8 to 14 years, with Tourette's disorder and attention-deficit hyperactivity disorder were studied in an ON, OFF, ON design. Subjects were admitted to a research unit for observation and videotaping. At Visit 1, blinded 5-min tic counts and nonblinded clinicians' tic ratings (Challenge-Yale Global Tic Severity Scale [C-YGTSS]) were obtained at 7 time points throughout the day, while subjects continued to take their clinically prescribed doses of MPH (mean daily dose 0.5 mg/kg, range 0.2 to 1.0). MPH was discontinued following Visit 1. Two weeks later each subject was readmitted for Visit 2, which was identical to Visit 1 except that no MPH was given. MPH was then reinitiated, and each subject was readmitted 4 weeks later for Visit 3. Mean blinded tic counts and C-YGTSS scores were significantly higher at Visits 1 and 3 (on MPH) than Visit 2 (off MPH). Clinically meaningful changes were observed in all five subjects. Tic frequency and severity diminished after discontinuation of MPH for 2 weeks and increased after reinitiation of MPH for 4 weeks, despite the relatively low doses employed. Further study is required to reconcile these findings with other recent short-term treatment studies that have found no consistent effect of stimulant medication on tic severity. For now, caution and close monitoring appear warranted when children with tic disorders receive long-term treatment with stimulant medication.